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<!doctype html><html lang="en-GB-oxendict"> <head><meta charset="utf-8"><meta property="og:image" content="https://tc39.es/ecmarkup/ecma-logo.png"><meta property="og:title" content="ECMAScript® 2025 Language Specification"><meta property="og:description" content="Introduction This Ecma Standard defines the ECMAScript 2025 Language. It is the sixteenth edition of the ECMAScript Language Specification. Since publication of the first edition in 1997, ECMAScript has grown to be one of the world's most widely used general-purpose programming languages. It is"> <link rel="icon" href="../img/favicon.ico"> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.0.1/styles/base16/solarized-light.min.css"><link rel="stylesheet" href="../assets/ecmarkup.css"><link rel="stylesheet" href="../assets/print.css" media="print"><style> #metadata-block { margin: 4em 0; padding: 10px; border: 1px solid #ee8421; } #metadata-block h1 { font-size: 1.5em; margin-top: 0; } #metadata-block > ul { list-style-type: none; margin: 0; padding: 0; } #ecma-logo { width: 500px; } .unicode-property-table { table-layout: fixed; width: 100%; font-size: 80%; } .corner-cell { position: relative; height: 2lh; } .corner-cell .slash { position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: linear-gradient(to bottom left, transparent calc(50% - 1px), gray, transparent calc(50% + 1px)); } .corner-cell > .column { position: absolute; bottom: 0.4em; left: 1em; } .corner-cell > .row { position: absolute; top: 0.4em; right: 1em; } </style> <title>ECMAScript® 2025 Language Specification</title><script src="../assets/multipage.js?cache=PxlMRbFW" defer=""></script><script src="../assets/ecmarkup.js?cache=Rn5g_R02" defer=""></script><style> @media print { @page :left { @bottom-right { content: '© Ecma International 2024'; } } @page :right { @bottom-left { content: '© Ecma International 2024'; } } @page :first { @bottom-left { content: ''; } @bottom-right { content: ''; } } @page :blank { @bottom-left { content: ''; } @bottom-right { content: ''; } } } </style><link rel="canonical" href="../#sec-ecmascript-language-statements-and-declarations"></head> <body><div id="menu"><div id="menu-search"><input type="text" id="menu-search-box" placeholder="Search..."><div id="menu-search-results" class="inactive"></div></div><div id="menu-pins"><div class="menu-pane-header">Pins<button class="unpin-all">clear</button></div><ul id="menu-pins-list"></ul></div><div class="menu-pane-header">Table of Contents</div><div id="menu-toc"><ol class="toc"><li><a href="./#sec-intro" title="Introduction">Introduction</a></li><li><a href="scope.html#sec-scope" title="Scope">1 Scope</a></li><li>+<a href="conformance.html#sec-conformance" title="Conformance">2 Conformance</a><ol class="toc"><li><a href="conformance.html#sec-conformance-normative-optional" title="Example Normative Optional Clause Heading">2.1 Example Normative Optional Clause Heading</a></li><li><a href="conformance.html#sec-conformance-legacy" title="Example Legacy Clause Heading">2.2 Example Legacy Clause Heading</a></li><li><a href="conformance.html#sec-conformance-legacy-normative-optional" title="Example Legacy Normative Optional Clause Heading">2.3 Example Legacy Normative Optional Clause Heading</a></li></ol></li><li><a href="normative-references.html#sec-normative-references" title="Normative References">3 Normative References</a></li><li>+<a href="overview.html#sec-overview" title="Overview">4 Overview</a><ol class="toc"><li><a href="overview.html#sec-web-scripting" title="Web Scripting">4.1 Web Scripting</a></li><li><a href="overview.html#sec-hosts-and-implementations" title="Hosts and Implementations">4.2 Hosts and Implementations</a></li><li>+<a href="overview.html#sec-ecmascript-overview" title="ECMAScript Overview">4.3 ECMAScript Overview</a><ol class="toc"><li><a href="overview.html#sec-objects" title="Objects">4.3.1 Objects</a></li><li><a href="overview.html#sec-strict-variant-of-ecmascript" title="The Strict Variant of ECMAScript">4.3.2 The Strict Variant of ECMAScript</a></li></ol></li><li>+<a href="overview.html#sec-terms-and-definitions" title="Terms and Definitions">4.4 Terms and Definitions</a><ol class="toc"><li><a href="overview.html#sec-terms-and-definitions-implementation-approximated" title="implementation-approximated">4.4.1 implementation-approximated</a></li><li><a href="overview.html#sec-terms-and-definitions-implementation-defined" title="implementation-defined">4.4.2 implementation-defined</a></li><li><a href="overview.html#sec-terms-and-definitions-host-defined" title="host-defined">4.4.3 host-defined</a></li><li><a href="overview.html#sec-type" title="type">4.4.4 type</a></li><li><a href="overview.html#sec-primitive-value" title="primitive value">4.4.5 primitive value</a></li><li><a href="overview.html#sec-terms-and-definitions-object" title="object">4.4.6 object</a></li><li><a href="overview.html#sec-constructor" title="constructor">4.4.7 constructor</a></li><li><a href="overview.html#sec-terms-and-definitions-prototype" title="prototype">4.4.8 prototype</a></li><li><a href="overview.html#sec-ordinary-object" title="ordinary object">4.4.9 ordinary object</a></li><li><a href="overview.html#sec-exotic-object" title="exotic object">4.4.10 exotic object</a></li><li><a href="overview.html#sec-standard-object" title="standard object">4.4.11 standard object</a></li><li><a href="overview.html#sec-built-in-object" title="built-in object">4.4.12 built-in object</a></li><li><a href="overview.html#sec-undefined-value" title="undefined value">4.4.13 undefined value</a></li><li><a href="overview.html#sec-terms-and-definitions-undefined-type" title="Undefined type">4.4.14 Undefined type</a></li><li><a href="overview.html#sec-null-value" title="null value">4.4.15 null value</a></li><li><a href="overview.html#sec-terms-and-definitions-null-type" title="Null type">4.4.16 Null type</a></li><li><a href="overview.html#sec-terms-and-definitions-boolean-value" title="Boolean value">4.4.17 Boolean value</a></li><li><a href="overview.html#sec-terms-and-definitions-boolean-type" title="Boolean type">4.4.18 Boolean type</a></li><li><a href="overview.html#sec-boolean-object" title="Boolean object">4.4.19 Boolean object</a></li><li><a href="overview.html#sec-terms-and-definitions-string-value" title="String value">4.4.20 String value</a></li><li><a href="overview.html#sec-terms-and-definitions-string-type" title="String type">4.4.21 String type</a></li><li><a href="overview.html#sec-string-object" title="String object">4.4.22 String object</a></li><li><a href="overview.html#sec-terms-and-definitions-number-value" title="Number value">4.4.23 Number value</a></li><li><a href="overview.html#sec-terms-and-definitions-number-type" title="Number type">4.4.24 Number type</a></li><li><a href="overview.html#sec-number-object" title="Number object">4.4.25 Number object</a></li><li><a href="overview.html#sec-terms-and-definitions-infinity" title="Infinity">4.4.26 Infinity</a></li><li><a href="overview.html#sec-terms-and-definitions-nan" title="NaN">4.4.27 NaN</a></li><li><a href="overview.html#sec-terms-and-definitions-bigint-value" title="BigInt value">4.4.28 BigInt value</a></li><li><a href="overview.html#sec-terms-and-definitions-bigint-type" title="BigInt type">4.4.29 BigInt type</a></li><li><a href="overview.html#sec-bigint-object" title="BigInt object">4.4.30 BigInt object</a></li><li><a href="overview.html#sec-symbol-value" title="Symbol value">4.4.31 Symbol value</a></li><li><a href="overview.html#sec-terms-and-definitions-symbol-type" title="Symbol type">4.4.32 Symbol type</a></li><li><a href="overview.html#sec-symbol-object" title="Symbol object">4.4.33 Symbol object</a></li><li><a href="overview.html#sec-terms-and-definitions-function" title="function">4.4.34 function</a></li><li><a href="overview.html#sec-built-in-function" title="built-in function">4.4.35 built-in function</a></li><li><a href="overview.html#sec-built-in-constructor" title="built-in constructor">4.4.36 built-in constructor</a></li><li><a href="overview.html#sec-property" title="property">4.4.37 property</a></li><li><a href="overview.html#sec-method" title="method">4.4.38 method</a></li><li><a href="overview.html#sec-built-in-method" title="built-in method">4.4.39 built-in method</a></li><li><a href="overview.html#sec-attribute" title="attribute">4.4.40 attribute</a></li><li><a href="overview.html#sec-own-property" title="own property">4.4.41 own property</a></li><li><a href="overview.html#sec-inherited-property" title="inherited property">4.4.42 inherited property</a></li></ol></li><li><a href="overview.html#sec-organization-of-this-specification" title="Organization of This Specification">4.5 Organization of This Specification</a></li></ol></li><li>+<a href="notational-conventions.html#sec-notational-conventions" title="Notational Conventions">5 Notational Conventions</a><ol class="toc"><li>+<a href="notational-conventions.html#sec-syntactic-and-lexical-grammars" title="Syntactic and Lexical Grammars">5.1 Syntactic and Lexical Grammars</a><ol class="toc"><li><a href="notational-conventions.html#sec-context-free-grammars" title="Context-Free Grammars">5.1.1 Context-Free Grammars</a></li><li><a href="notational-conventions.html#sec-lexical-and-regexp-grammars" title="The Lexical and RegExp Grammars">5.1.2 The Lexical and RegExp Grammars</a></li><li><a href="notational-conventions.html#sec-numeric-string-grammar" title="The Numeric String Grammar">5.1.3 The Numeric String Grammar</a></li><li><a href="notational-conventions.html#sec-syntactic-grammar" title="The Syntactic Grammar">5.1.4 The Syntactic Grammar</a></li><li>+<a href="notational-conventions.html#sec-grammar-notation" title="Grammar Notation">5.1.5 Grammar Notation</a><ol class="toc"><li><a href="notational-conventions.html#sec-terminal-symbols" title="Terminal Symbols">5.1.5.1 Terminal Symbols</a></li><li><a href="notational-conventions.html#sec-nonterminal-symbols-and-productions" title="Nonterminal Symbols and Productions">5.1.5.2 Nonterminal Symbols and Productions</a></li><li><a href="notational-conventions.html#sec-optional-symbols" title="Optional Symbols">5.1.5.3 Optional Symbols</a></li><li><a href="notational-conventions.html#sec-grammatical-parameters" title="Grammatical Parameters">5.1.5.4 Grammatical Parameters</a></li><li><a href="notational-conventions.html#sec-one-of" title="one of">5.1.5.5 one of</a></li><li><a href="notational-conventions.html#sec-empty" title="[empty]">5.1.5.6 [empty]</a></li><li><a href="notational-conventions.html#sec-lookahead-restrictions" title="Lookahead Restrictions">5.1.5.7 Lookahead Restrictions</a></li><li><a href="notational-conventions.html#sec-no-lineterminator-here" title="[no LineTerminator here]">5.1.5.8 [no <emu-nt>LineTerminator</emu-nt> here]</a></li><li><a href="notational-conventions.html#sec-but-not" title="but not">5.1.5.9 but not</a></li><li><a href="notational-conventions.html#sec-descriptive-phrases" title="Descriptive Phrases">5.1.5.10 Descriptive Phrases</a></li></ol></li></ol></li><li>+<a href="notational-conventions.html#sec-algorithm-conventions" title="Algorithm Conventions">5.2 Algorithm Conventions</a><ol class="toc"><li><a href="notational-conventions.html#sec-algorithm-conventions-abstract-operations" title="Abstract Operations">5.2.1 Abstract Operations</a></li><li><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations" title="Syntax-Directed Operations">5.2.2 Syntax-Directed Operations</a></li><li>+<a href="notational-conventions.html#sec-runtime-semantics" title="Runtime Semantics">5.2.3 Runtime Semantics</a><ol class="toc"><li><a href="notational-conventions.html#sec-completion-ao" title="Completion ( completionRecord )">5.2.3.1 Completion ( <var>completionRecord</var> )</a></li><li><a href="notational-conventions.html#sec-throw-an-exception" title="Throw an Exception">5.2.3.2 Throw an Exception</a></li><li><a href="notational-conventions.html#sec-returnifabrupt" title="ReturnIfAbrupt">5.2.3.3 ReturnIfAbrupt</a></li><li><a href="notational-conventions.html#sec-returnifabrupt-shorthands" title="ReturnIfAbrupt Shorthands">5.2.3.4 ReturnIfAbrupt Shorthands</a></li><li><a href="notational-conventions.html#sec-implicit-normal-completion" title="Implicit Normal Completion">5.2.3.5 Implicit Normal Completion</a></li></ol></li><li><a href="notational-conventions.html#sec-static-semantic-rules" title="Static Semantics">5.2.4 Static Semantics</a></li><li><a href="notational-conventions.html#sec-mathematical-operations" title="Mathematical Operations">5.2.5 Mathematical Operations</a></li><li><a href="notational-conventions.html#sec-value-notation" title="Value Notation">5.2.6 Value Notation</a></li><li><a href="notational-conventions.html#sec-identity" title="Identity">5.2.7 Identity</a></li></ol></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-data-types-and-values" title="ECMAScript Data Types and Values">6 ECMAScript Data Types and Values</a><ol class="toc"><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types" title="ECMAScript Language Types">6.1 ECMAScript Language Types</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-undefined-type" title="The Undefined Type">6.1.1 The Undefined Type</a></li><li><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-null-type" title="The Null Type">6.1.2 The Null Type</a></li><li><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-boolean-type" title="The Boolean Type">6.1.3 The Boolean Type</a></li><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-string-type" title="The String Type">6.1.4 The String Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-stringindexof" title="StringIndexOf ( string, searchValue, fromIndex )">6.1.4.1 StringIndexOf ( <var>string</var>, <var>searchValue</var>, <var>fromIndex</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-stringlastindexof" title="StringLastIndexOf ( string, searchValue, fromIndex )">6.1.4.2 StringLastIndexOf ( <var>string</var>, <var>searchValue</var>, <var>fromIndex</var> )</a></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-symbol-type" title="The Symbol Type">6.1.5 The Symbol Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-well-known-symbols" title="Well-Known Symbols">6.1.5.1 Well-Known Symbols</a></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-numeric-types" title="Numeric Types">6.1.6 Numeric Types</a><ol class="toc"><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-number-type" title="The Number Type">6.1.6.1 The Number Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-unaryMinus" title="Number::unaryMinus ( x )">6.1.6.1.1 Number::unaryMinus ( <var>x</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-bitwiseNOT" title="Number::bitwiseNOT ( x )">6.1.6.1.2 Number::bitwiseNOT ( <var>x</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-exponentiate" title="Number::exponentiate ( base, exponent )">6.1.6.1.3 Number::exponentiate ( <var>base</var>, <var>exponent</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-multiply" title="Number::multiply ( x, y )">6.1.6.1.4 Number::multiply ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-divide" title="Number::divide ( x, y )">6.1.6.1.5 Number::divide ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-remainder" title="Number::remainder ( n, d )">6.1.6.1.6 Number::remainder ( <var>n</var>, <var>d</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-add" title="Number::add ( x, y )">6.1.6.1.7 Number::add ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-subtract" title="Number::subtract ( x, y )">6.1.6.1.8 Number::subtract ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-leftShift" title="Number::leftShift ( x, y )">6.1.6.1.9 Number::leftShift ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-signedRightShift" title="Number::signedRightShift ( x, y )">6.1.6.1.10 Number::signedRightShift ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-unsignedRightShift" title="Number::unsignedRightShift ( x, y )">6.1.6.1.11 Number::unsignedRightShift ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-lessThan" title="Number::lessThan ( x, y )">6.1.6.1.12 Number::lessThan ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-equal" title="Number::equal ( x, y )">6.1.6.1.13 Number::equal ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-sameValue" title="Number::sameValue ( x, y )">6.1.6.1.14 Number::sameValue ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-sameValueZero" title="Number::sameValueZero ( x, y )">6.1.6.1.15 Number::sameValueZero ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numberbitwiseop" title="NumberBitwiseOp ( op, x, y )">6.1.6.1.16 NumberBitwiseOp ( <var>op</var>, <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-bitwiseAND" title="Number::bitwiseAND ( x, y )">6.1.6.1.17 Number::bitwiseAND ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-bitwiseXOR" title="Number::bitwiseXOR ( x, y )">6.1.6.1.18 Number::bitwiseXOR ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-bitwiseOR" title="Number::bitwiseOR ( x, y )">6.1.6.1.19 Number::bitwiseOR ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-number-tostring" title="Number::toString ( x, radix )">6.1.6.1.20 Number::toString ( <var>x</var>, <var>radix</var> )</a></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-bigint-type" title="The BigInt Type">6.1.6.2 The BigInt Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-unaryMinus" title="BigInt::unaryMinus ( x )">6.1.6.2.1 BigInt::unaryMinus ( <var>x</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-bitwiseNOT" title="BigInt::bitwiseNOT ( x )">6.1.6.2.2 BigInt::bitwiseNOT ( <var>x</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-exponentiate" title="BigInt::exponentiate ( base, exponent )">6.1.6.2.3 BigInt::exponentiate ( <var>base</var>, <var>exponent</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-multiply" title="BigInt::multiply ( x, y )">6.1.6.2.4 BigInt::multiply ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-divide" title="BigInt::divide ( x, y )">6.1.6.2.5 BigInt::divide ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-remainder" title="BigInt::remainder ( n, d )">6.1.6.2.6 BigInt::remainder ( <var>n</var>, <var>d</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-add" title="BigInt::add ( x, y )">6.1.6.2.7 BigInt::add ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-subtract" title="BigInt::subtract ( x, y )">6.1.6.2.8 BigInt::subtract ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-leftShift" title="BigInt::leftShift ( x, y )">6.1.6.2.9 BigInt::leftShift ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-signedRightShift" title="BigInt::signedRightShift ( x, y )">6.1.6.2.10 BigInt::signedRightShift ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-unsignedRightShift" title="BigInt::unsignedRightShift ( x, y )">6.1.6.2.11 BigInt::unsignedRightShift ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-lessThan" title="BigInt::lessThan ( x, y )">6.1.6.2.12 BigInt::lessThan ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-equal" title="BigInt::equal ( x, y )">6.1.6.2.13 BigInt::equal ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-binaryand" title="BinaryAnd ( x, y )">6.1.6.2.14 BinaryAnd ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-binaryor" title="BinaryOr ( x, y )">6.1.6.2.15 BinaryOr ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-binaryxor" title="BinaryXor ( x, y )">6.1.6.2.16 BinaryXor ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-bigintbitwiseop" title="BigIntBitwiseOp ( op, x, y )">6.1.6.2.17 BigIntBitwiseOp ( <var>op</var>, <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-bitwiseAND" title="BigInt::bitwiseAND ( x, y )">6.1.6.2.18 BigInt::bitwiseAND ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-bitwiseXOR" title="BigInt::bitwiseXOR ( x, y )">6.1.6.2.19 BigInt::bitwiseXOR ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-bitwiseOR" title="BigInt::bitwiseOR ( x, y )">6.1.6.2.20 BigInt::bitwiseOR ( <var>x</var>, <var>y</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-numeric-types-bigint-tostring" title="BigInt::toString ( x, radix )">6.1.6.2.21 BigInt::toString ( <var>x</var>, <var>radix</var> )</a></li></ol></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-object-type" title="The Object Type">6.1.7 The Object Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-property-attributes" title="Property Attributes">6.1.7.1 Property Attributes</a></li><li><a href="ecmascript-data-types-and-values.html#sec-object-internal-methods-and-internal-slots" title="Object Internal Methods and Internal Slots">6.1.7.2 Object Internal Methods and Internal Slots</a></li><li><a href="ecmascript-data-types-and-values.html#sec-invariants-of-the-essential-internal-methods" title="Invariants of the Essential Internal Methods">6.1.7.3 Invariants of the Essential Internal Methods</a></li><li><a href="ecmascript-data-types-and-values.html#sec-well-known-intrinsic-objects" title="Well-Known Intrinsic Objects">6.1.7.4 Well-Known Intrinsic Objects</a></li></ol></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-ecmascript-specification-types" title="ECMAScript Specification Types">6.2 ECMAScript Specification Types</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-enum-specification-type" title="The Enum Specification Type">6.2.1 The Enum Specification Type</a></li><li><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type" title="The List and Record Specification Types">6.2.2 The List and Record Specification Types</a></li><li><a href="ecmascript-data-types-and-values.html#sec-set-and-relation-specification-type" title="The Set and Relation Specification Types">6.2.3 The Set and Relation Specification Types</a></li><li>+<a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type" title="The Completion Record Specification Type">6.2.4 The Completion Record Specification Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-normalcompletion" title="NormalCompletion ( value )">6.2.4.1 NormalCompletion ( <var>value</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-throwcompletion" title="ThrowCompletion ( value )">6.2.4.2 ThrowCompletion ( <var>value</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-returncompletion" title="ReturnCompletion ( value )">6.2.4.3 ReturnCompletion ( <var>value</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-updateempty" title="UpdateEmpty ( completionRecord, value )">6.2.4.4 UpdateEmpty ( <var>completionRecord</var>, <var>value</var> )</a></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-reference-record-specification-type" title="The Reference Record Specification Type">6.2.5 The Reference Record Specification Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-ispropertyreference" title="IsPropertyReference ( V )">6.2.5.1 IsPropertyReference ( <var>V</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-isunresolvablereference" title="IsUnresolvableReference ( V )">6.2.5.2 IsUnresolvableReference ( <var>V</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-issuperreference" title="IsSuperReference ( V )">6.2.5.3 IsSuperReference ( <var>V</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-isprivatereference" title="IsPrivateReference ( V )">6.2.5.4 IsPrivateReference ( <var>V</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-getvalue" title="GetValue ( V )">6.2.5.5 GetValue ( <var>V</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-putvalue" title="PutValue ( V, W )">6.2.5.6 PutValue ( <var>V</var>, <var>W</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-getthisvalue" title="GetThisValue ( V )">6.2.5.7 GetThisValue ( <var>V</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-initializereferencedbinding" title="InitializeReferencedBinding ( V, W )">6.2.5.8 InitializeReferencedBinding ( <var>V</var>, <var>W</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-makeprivatereference" title="MakePrivateReference ( baseValue, privateIdentifier )">6.2.5.9 MakePrivateReference ( <var>baseValue</var>, <var>privateIdentifier</var> )</a></li></ol></li><li>+<a href="ecmascript-data-types-and-values.html#sec-property-descriptor-specification-type" title="The Property Descriptor Specification Type">6.2.6 The Property Descriptor Specification Type</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-isaccessordescriptor" title="IsAccessorDescriptor ( Desc )">6.2.6.1 IsAccessorDescriptor ( <var>Desc</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-isdatadescriptor" title="IsDataDescriptor ( Desc )">6.2.6.2 IsDataDescriptor ( <var>Desc</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-isgenericdescriptor" title="IsGenericDescriptor ( Desc )">6.2.6.3 IsGenericDescriptor ( <var>Desc</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-frompropertydescriptor" title="FromPropertyDescriptor ( Desc )">6.2.6.4 FromPropertyDescriptor ( <var>Desc</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-topropertydescriptor" title="ToPropertyDescriptor ( Obj )">6.2.6.5 ToPropertyDescriptor ( <var>Obj</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-completepropertydescriptor" title="CompletePropertyDescriptor ( Desc )">6.2.6.6 CompletePropertyDescriptor ( <var>Desc</var> )</a></li></ol></li><li><a href="ecmascript-data-types-and-values.html#sec-lexical-environment-and-environment-record-specification-types" title="The Environment Record Specification Type">6.2.7 The Environment Record Specification Type</a></li><li><a href="ecmascript-data-types-and-values.html#sec-abstract-closure" title="The Abstract Closure Specification Type">6.2.8 The Abstract Closure Specification Type</a></li><li>+<a href="ecmascript-data-types-and-values.html#sec-data-blocks" title="Data Blocks">6.2.9 Data Blocks</a><ol class="toc"><li><a href="ecmascript-data-types-and-values.html#sec-createbytedatablock" title="CreateByteDataBlock ( size )">6.2.9.1 CreateByteDataBlock ( <var>size</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-createsharedbytedatablock" title="CreateSharedByteDataBlock ( size )">6.2.9.2 CreateSharedByteDataBlock ( <var>size</var> )</a></li><li><a href="ecmascript-data-types-and-values.html#sec-copydatablockbytes" title="CopyDataBlockBytes ( toBlock, toIndex, fromBlock, fromIndex, count )">6.2.9.3 CopyDataBlockBytes ( <var>toBlock</var>, <var>toIndex</var>, <var>fromBlock</var>, <var>fromIndex</var>, <var>count</var> )</a></li></ol></li><li><a href="ecmascript-data-types-and-values.html#sec-privateelement-specification-type" title="The PrivateElement Specification Type">6.2.10 The PrivateElement Specification Type</a></li><li><a href="ecmascript-data-types-and-values.html#sec-classfielddefinition-record-specification-type" title="The ClassFieldDefinition Record Specification Type">6.2.11 The ClassFieldDefinition Record Specification Type</a></li><li><a href="ecmascript-data-types-and-values.html#sec-private-names" title="Private Names">6.2.12 Private Names</a></li><li><a href="ecmascript-data-types-and-values.html#sec-classstaticblockdefinition-record-specification-type" title="The ClassStaticBlockDefinition Record Specification Type">6.2.13 The ClassStaticBlockDefinition Record Specification Type</a></li></ol></li></ol></li><li>+<a href="abstract-operations.html#sec-abstract-operations" title="Abstract Operations">7 Abstract Operations</a><ol class="toc"><li>+<a href="abstract-operations.html#sec-type-conversion" title="Type Conversion">7.1 Type Conversion</a><ol class="toc"><li>+<a href="abstract-operations.html#sec-toprimitive" title="ToPrimitive ( input [ , preferredType ] )">7.1.1 ToPrimitive ( <var>input</var> [ , <var>preferredType</var> ] )</a><ol class="toc"><li><a href="abstract-operations.html#sec-ordinarytoprimitive" title="OrdinaryToPrimitive ( O, hint )">7.1.1.1 OrdinaryToPrimitive ( <var>O</var>, <var>hint</var> )</a></li></ol></li><li><a href="abstract-operations.html#sec-toboolean" title="ToBoolean ( argument )">7.1.2 ToBoolean ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-tonumeric" title="ToNumeric ( value )">7.1.3 ToNumeric ( <var>value</var> )</a></li><li>+<a href="abstract-operations.html#sec-tonumber" title="ToNumber ( argument )">7.1.4 ToNumber ( <var>argument</var> )</a><ol class="toc"><li>+<a href="abstract-operations.html#sec-tonumber-applied-to-the-string-type" title="ToNumber Applied to the String Type">7.1.4.1 ToNumber Applied to the String Type</a><ol class="toc"><li><a href="abstract-operations.html#sec-stringtonumber" title="StringToNumber ( str )">7.1.4.1.1 StringToNumber ( <var>str</var> )</a></li><li><a href="abstract-operations.html#sec-runtime-semantics-stringnumericvalue" title="Runtime Semantics: StringNumericValue">7.1.4.1.2 RS: StringNumericValue</a></li><li><a href="abstract-operations.html#sec-roundmvresult" title="RoundMVResult ( n )">7.1.4.1.3 RoundMVResult ( <var>n</var> )</a></li></ol></li></ol></li><li><a href="abstract-operations.html#sec-tointegerorinfinity" title="ToIntegerOrInfinity ( argument )">7.1.5 ToIntegerOrInfinity ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-toint32" title="ToInt32 ( argument )">7.1.6 ToInt32 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-touint32" title="ToUint32 ( argument )">7.1.7 ToUint32 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-toint16" title="ToInt16 ( argument )">7.1.8 ToInt16 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-touint16" title="ToUint16 ( argument )">7.1.9 ToUint16 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-toint8" title="ToInt8 ( argument )">7.1.10 ToInt8 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-touint8" title="ToUint8 ( argument )">7.1.11 ToUint8 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-touint8clamp" title="ToUint8Clamp ( argument )">7.1.12 ToUint8Clamp ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-tobigint" title="ToBigInt ( argument )">7.1.13 ToBigInt ( <var>argument</var> )</a></li><li>+<a href="abstract-operations.html#sec-stringtobigint" title="StringToBigInt ( str )">7.1.14 StringToBigInt ( <var>str</var> )</a><ol class="toc"><li><a href="abstract-operations.html#sec-stringintegerliteral-grammar" title="StringIntegerLiteral Grammar">7.1.14.1 StringIntegerLiteral Grammar</a></li><li><a href="abstract-operations.html#sec-runtime-semantics-mv-for-stringintegerliteral" title="Runtime Semantics: MV">7.1.14.2 RS: MV</a></li></ol></li><li><a href="abstract-operations.html#sec-tobigint64" title="ToBigInt64 ( argument )">7.1.15 ToBigInt64 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-tobiguint64" title="ToBigUint64 ( argument )">7.1.16 ToBigUint64 ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-tostring" title="ToString ( argument )">7.1.17 ToString ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-toobject" title="ToObject ( argument )">7.1.18 ToObject ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-topropertykey" title="ToPropertyKey ( argument )">7.1.19 ToPropertyKey ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-tolength" title="ToLength ( argument )">7.1.20 ToLength ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-canonicalnumericindexstring" title="CanonicalNumericIndexString ( argument )">7.1.21 CanonicalNumericIndexString ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-toindex" title="ToIndex ( value )">7.1.22 ToIndex ( <var>value</var> )</a></li></ol></li><li>+<a href="abstract-operations.html#sec-testing-and-comparison-operations" title="Testing and Comparison Operations">7.2 Testing and Comparison Operations</a><ol class="toc"><li><a href="abstract-operations.html#sec-requireobjectcoercible" title="RequireObjectCoercible ( argument )">7.2.1 RequireObjectCoercible ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-isarray" title="IsArray ( argument )">7.2.2 IsArray ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-iscallable" title="IsCallable ( argument )">7.2.3 IsCallable ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-isconstructor" title="IsConstructor ( argument )">7.2.4 IsConstructor ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-isextensible-o" title="IsExtensible ( O )">7.2.5 IsExtensible ( <var>O</var> )</a></li><li><a href="abstract-operations.html#sec-isregexp" title="IsRegExp ( argument )">7.2.6 IsRegExp ( <var>argument</var> )</a></li><li><a href="abstract-operations.html#sec-isstringwellformedunicode" title="Static Semantics: IsStringWellFormedUnicode ( string )">7.2.7 SS: IsStringWellFormedUnicode ( <var>string</var> )</a></li><li><a href="abstract-operations.html#sec-sametype" title="SameType ( x, y )">7.2.8 SameType ( <var>x</var>, <var>y</var> )</a></li><li><a href="abstract-operations.html#sec-samevalue" title="SameValue ( x, y )">7.2.9 SameValue ( <var>x</var>, <var>y</var> )</a></li><li><a href="abstract-operations.html#sec-samevaluezero" title="SameValueZero ( x, y )">7.2.10 SameValueZero ( <var>x</var>, <var>y</var> )</a></li><li><a href="abstract-operations.html#sec-samevaluenonnumber" title="SameValueNonNumber ( x, y )">7.2.11 SameValueNonNumber ( <var>x</var>, <var>y</var> )</a></li><li><a href="abstract-operations.html#sec-islessthan" title="IsLessThan ( x, y, LeftFirst )">7.2.12 IsLessThan ( <var>x</var>, <var>y</var>, <var>LeftFirst</var> )</a></li><li><a href="abstract-operations.html#sec-islooselyequal" title="IsLooselyEqual ( x, y )">7.2.13 IsLooselyEqual ( <var>x</var>, <var>y</var> )</a></li><li><a href="abstract-operations.html#sec-isstrictlyequal" title="IsStrictlyEqual ( x, y )">7.2.14 IsStrictlyEqual ( <var>x</var>, <var>y</var> )</a></li></ol></li><li>+<a href="abstract-operations.html#sec-operations-on-objects" title="Operations on Objects">7.3 Operations on Objects</a><ol class="toc"><li><a href="abstract-operations.html#sec-makebasicobject" title="MakeBasicObject ( internalSlotsList )">7.3.1 MakeBasicObject ( <var>internalSlotsList</var> )</a></li><li><a href="abstract-operations.html#sec-get-o-p" title="Get ( O, P )">7.3.2 Get ( <var>O</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-getv" title="GetV ( V, P )">7.3.3 GetV ( <var>V</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-set-o-p-v-throw" title="Set ( O, P, V, Throw )">7.3.4 Set ( <var>O</var>, <var>P</var>, <var>V</var>, <var>Throw</var> )</a></li><li><a href="abstract-operations.html#sec-createdataproperty" title="CreateDataProperty ( O, P, V )">7.3.5 CreateDataProperty ( <var>O</var>, <var>P</var>, <var>V</var> )</a></li><li><a href="abstract-operations.html#sec-createdatapropertyorthrow" title="CreateDataPropertyOrThrow ( O, P, V )">7.3.6 CreateDataPropertyOrThrow ( <var>O</var>, <var>P</var>, <var>V</var> )</a></li><li><a href="abstract-operations.html#sec-createnonenumerabledatapropertyorthrow" title="CreateNonEnumerableDataPropertyOrThrow ( O, P, V )">7.3.7 CreateNonEnumerableDataPropertyOrThrow ( <var>O</var>, <var>P</var>, <var>V</var> )</a></li><li><a href="abstract-operations.html#sec-definepropertyorthrow" title="DefinePropertyOrThrow ( O, P, desc )">7.3.8 DefinePropertyOrThrow ( <var>O</var>, <var>P</var>, <var>desc</var> )</a></li><li><a href="abstract-operations.html#sec-deletepropertyorthrow" title="DeletePropertyOrThrow ( O, P )">7.3.9 DeletePropertyOrThrow ( <var>O</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-getmethod" title="GetMethod ( V, P )">7.3.10 GetMethod ( <var>V</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-hasproperty" title="HasProperty ( O, P )">7.3.11 HasProperty ( <var>O</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-hasownproperty" title="HasOwnProperty ( O, P )">7.3.12 HasOwnProperty ( <var>O</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-call" title="Call ( F, V [ , argumentsList ] )">7.3.13 Call ( <var>F</var>, <var>V</var> [ , <var>argumentsList</var> ] )</a></li><li><a href="abstract-operations.html#sec-construct" title="Construct ( F [ , argumentsList [ , newTarget ] ] )">7.3.14 Construct ( <var>F</var> [ , <var>argumentsList</var> [ , <var>newTarget</var> ] ] )</a></li><li><a href="abstract-operations.html#sec-setintegritylevel" title="SetIntegrityLevel ( O, level )">7.3.15 SetIntegrityLevel ( <var>O</var>, <var>level</var> )</a></li><li><a href="abstract-operations.html#sec-testintegritylevel" title="TestIntegrityLevel ( O, level )">7.3.16 TestIntegrityLevel ( <var>O</var>, <var>level</var> )</a></li><li><a href="abstract-operations.html#sec-createarrayfromlist" title="CreateArrayFromList ( elements )">7.3.17 CreateArrayFromList ( <var>elements</var> )</a></li><li><a href="abstract-operations.html#sec-lengthofarraylike" title="LengthOfArrayLike ( obj )">7.3.18 LengthOfArrayLike ( <var>obj</var> )</a></li><li><a href="abstract-operations.html#sec-createlistfromarraylike" title="CreateListFromArrayLike ( obj [ , validElementTypes ] )">7.3.19 CreateListFromArrayLike ( <var>obj</var> [ , <var>validElementTypes</var> ] )</a></li><li><a href="abstract-operations.html#sec-invoke" title="Invoke ( V, P [ , argumentsList ] )">7.3.20 Invoke ( <var>V</var>, <var>P</var> [ , <var>argumentsList</var> ] )</a></li><li><a href="abstract-operations.html#sec-ordinaryhasinstance" title="OrdinaryHasInstance ( C, O )">7.3.21 OrdinaryHasInstance ( <var>C</var>, <var>O</var> )</a></li><li><a href="abstract-operations.html#sec-speciesconstructor" title="SpeciesConstructor ( O, defaultConstructor )">7.3.22 SpeciesConstructor ( <var>O</var>, <var>defaultConstructor</var> )</a></li><li><a href="abstract-operations.html#sec-enumerableownproperties" title="EnumerableOwnProperties ( O, kind )">7.3.23 EnumerableOwnProperties ( <var>O</var>, <var>kind</var> )</a></li><li><a href="abstract-operations.html#sec-getfunctionrealm" title="GetFunctionRealm ( obj )">7.3.24 GetFunctionRealm ( <var>obj</var> )</a></li><li><a href="abstract-operations.html#sec-copydataproperties" title="CopyDataProperties ( target, source, excludedItems )">7.3.25 CopyDataProperties ( <var>target</var>, <var>source</var>, <var>excludedItems</var> )</a></li><li><a href="abstract-operations.html#sec-privateelementfind" title="PrivateElementFind ( O, P )">7.3.26 PrivateElementFind ( <var>O</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-privatefieldadd" title="PrivateFieldAdd ( O, P, value )">7.3.27 PrivateFieldAdd ( <var>O</var>, <var>P</var>, <var>value</var> )</a></li><li><a href="abstract-operations.html#sec-privatemethodoraccessoradd" title="PrivateMethodOrAccessorAdd ( O, method )">7.3.28 PrivateMethodOrAccessorAdd ( <var>O</var>, <var>method</var> )</a></li><li><a href="abstract-operations.html#sec-hostensurecanaddprivateelement" title="HostEnsureCanAddPrivateElement ( O )">7.3.29 HostEnsureCanAddPrivateElement ( <var>O</var> )</a></li><li><a href="abstract-operations.html#sec-privateget" title="PrivateGet ( O, P )">7.3.30 PrivateGet ( <var>O</var>, <var>P</var> )</a></li><li><a href="abstract-operations.html#sec-privateset" title="PrivateSet ( O, P, value )">7.3.31 PrivateSet ( <var>O</var>, <var>P</var>, <var>value</var> )</a></li><li><a href="abstract-operations.html#sec-definefield" title="DefineField ( receiver, fieldRecord )">7.3.32 DefineField ( <var>receiver</var>, <var>fieldRecord</var> )</a></li><li><a href="abstract-operations.html#sec-initializeinstanceelements" title="InitializeInstanceElements ( O, constructor )">7.3.33 InitializeInstanceElements ( <var>O</var>, <var>constructor</var> )</a></li><li><a href="abstract-operations.html#sec-add-value-to-keyed-group" title="AddValueToKeyedGroup ( groups, key, value )">7.3.34 AddValueToKeyedGroup ( <var>groups</var>, <var>key</var>, <var>value</var> )</a></li><li><a href="abstract-operations.html#sec-groupby" title="GroupBy ( items, callback, keyCoercion )">7.3.35 GroupBy ( <var>items</var>, <var>callback</var>, <var>keyCoercion</var> )</a></li><li><a href="abstract-operations.html#sec-SetterThatIgnoresPrototypeProperties" title="SetterThatIgnoresPrototypeProperties ( thisValue, home, p, v )">7.3.36 SetterThatIgnoresPrototypeProperties ( <var>thisValue</var>, <var>home</var>, <var>p</var>, <var>v</var> )</a></li></ol></li><li>+<a href="abstract-operations.html#sec-operations-on-iterator-objects" title="Operations on Iterator Objects">7.4 Operations on Iterator Objects</a><ol class="toc"><li><a href="abstract-operations.html#sec-iterator-records" title="Iterator Records">7.4.1 Iterator Records</a></li><li><a href="abstract-operations.html#sec-getiteratordirect" title="GetIteratorDirect ( obj )">7.4.2 GetIteratorDirect ( <var>obj</var> )</a></li><li><a href="abstract-operations.html#sec-getiteratorfrommethod" title="GetIteratorFromMethod ( obj, method )">7.4.3 GetIteratorFromMethod ( <var>obj</var>, <var>method</var> )</a></li><li><a href="abstract-operations.html#sec-getiterator" title="GetIterator ( obj, kind )">7.4.4 GetIterator ( <var>obj</var>, <var>kind</var> )</a></li><li><a href="abstract-operations.html#sec-getiteratorflattenable" title="GetIteratorFlattenable ( obj, primitiveHandling )">7.4.5 GetIteratorFlattenable ( <var>obj</var>, <var>primitiveHandling</var> )</a></li><li><a href="abstract-operations.html#sec-iteratornext" title="IteratorNext ( iteratorRecord [ , value ] )">7.4.6 IteratorNext ( <var>iteratorRecord</var> [ , <var>value</var> ] )</a></li><li><a href="abstract-operations.html#sec-iteratorcomplete" title="IteratorComplete ( iteratorResult )">7.4.7 IteratorComplete ( <var>iteratorResult</var> )</a></li><li><a href="abstract-operations.html#sec-iteratorvalue" title="IteratorValue ( iteratorResult )">7.4.8 IteratorValue ( <var>iteratorResult</var> )</a></li><li><a href="abstract-operations.html#sec-iteratorstep" title="IteratorStep ( iteratorRecord )">7.4.9 IteratorStep ( <var>iteratorRecord</var> )</a></li><li><a href="abstract-operations.html#sec-iteratorstepvalue" title="IteratorStepValue ( iteratorRecord )">7.4.10 IteratorStepValue ( <var>iteratorRecord</var> )</a></li><li><a href="abstract-operations.html#sec-iteratorclose" title="IteratorClose ( iteratorRecord, completion )">7.4.11 IteratorClose ( <var>iteratorRecord</var>, <var>completion</var> )</a></li><li><a href="abstract-operations.html#sec-ifabruptcloseiterator" title="IfAbruptCloseIterator ( value, iteratorRecord )">7.4.12 IfAbruptCloseIterator ( <var>value</var>, <var>iteratorRecord</var> )</a></li><li><a href="abstract-operations.html#sec-asynciteratorclose" title="AsyncIteratorClose ( iteratorRecord, completion )">7.4.13 AsyncIteratorClose ( <var>iteratorRecord</var>, <var>completion</var> )</a></li><li><a href="abstract-operations.html#sec-createiterresultobject" title="CreateIteratorResultObject ( value, done )">7.4.14 CreateIteratorResultObject ( <var>value</var>, <var>done</var> )</a></li><li><a href="abstract-operations.html#sec-createlistiteratorRecord" title="CreateListIteratorRecord ( list )">7.4.15 CreateListIteratorRecord ( <var>list</var> )</a></li><li><a href="abstract-operations.html#sec-iteratortolist" title="IteratorToList ( iteratorRecord )">7.4.16 IteratorToList ( <var>iteratorRecord</var> )</a></li></ol></li></ol></li><li>+<a href="syntax-directed-operations.html#sec-syntax-directed-operations" title="Syntax-Directed Operations">8 Syntax-Directed Operations</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-evaluation" title="Runtime Semantics: Evaluation">8.1 RS: Evaluation</a></li><li>+<a href="syntax-directed-operations.html#sec-syntax-directed-operations-scope-analysis" title="Scope Analysis">8.2 Scope Analysis</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-static-semantics-boundnames" title="Static Semantics: BoundNames">8.2.1 SS: BoundNames</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-declarationpart" title="Static Semantics: DeclarationPart">8.2.2 SS: DeclarationPart</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-isconstantdeclaration" title="Static Semantics: IsConstantDeclaration">8.2.3 SS: IsConstantDeclaration</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-lexicallydeclarednames" title="Static Semantics: LexicallyDeclaredNames">8.2.4 SS: LexicallyDeclaredNames</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-lexicallyscopeddeclarations" title="Static Semantics: LexicallyScopedDeclarations">8.2.5 SS: LexicallyScopedDeclarations</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-vardeclarednames" title="Static Semantics: VarDeclaredNames">8.2.6 SS: VarDeclaredNames</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-varscopeddeclarations" title="Static Semantics: VarScopedDeclarations">8.2.7 SS: VarScopedDeclarations</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-toplevellexicallydeclarednames" title="Static Semantics: TopLevelLexicallyDeclaredNames">8.2.8 SS: TopLevelLexicallyDeclaredNames</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-toplevellexicallyscopeddeclarations" title="Static Semantics: TopLevelLexicallyScopedDeclarations">8.2.9 SS: TopLevelLexicallyScopedDeclarations</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-toplevelvardeclarednames" title="Static Semantics: TopLevelVarDeclaredNames">8.2.10 SS: TopLevelVarDeclaredNames</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-toplevelvarscopeddeclarations" title="Static Semantics: TopLevelVarScopedDeclarations">8.2.11 SS: TopLevelVarScopedDeclarations</a></li></ol></li><li>+<a href="syntax-directed-operations.html#sec-syntax-directed-operations-labels" title="Labels">8.3 Labels</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-static-semantics-containsduplicatelabels" title="Static Semantics: ContainsDuplicateLabels">8.3.1 SS: ContainsDuplicateLabels</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-containsundefinedbreaktarget" title="Static Semantics: ContainsUndefinedBreakTarget">8.3.2 SS: ContainsUndefinedBreakTarget</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-containsundefinedcontinuetarget" title="Static Semantics: ContainsUndefinedContinueTarget">8.3.3 SS: ContainsUndefinedContinueTarget</a></li></ol></li><li>+<a href="syntax-directed-operations.html#sec-syntax-directed-operations-function-name-inference" title="Function Name Inference">8.4 Function Name Inference</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-static-semantics-hasname" title="Static Semantics: HasName">8.4.1 SS: HasName</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-isfunctiondefinition" title="Static Semantics: IsFunctionDefinition">8.4.2 SS: IsFunctionDefinition</a></li><li><a href="syntax-directed-operations.html#sec-isanonymousfunctiondefinition" title="Static Semantics: IsAnonymousFunctionDefinition ( expr )">8.4.3 SS: IsAnonymousFunctionDefinition ( <var>expr</var> )</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-isidentifierref" title="Static Semantics: IsIdentifierRef">8.4.4 SS: IsIdentifierRef</a></li><li><a href="syntax-directed-operations.html#sec-runtime-semantics-namedevaluation" title="Runtime Semantics: NamedEvaluation">8.4.5 RS: NamedEvaluation</a></li></ol></li><li>+<a href="syntax-directed-operations.html#sec-syntax-directed-operations-contains" title="Contains">8.5 Contains</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-static-semantics-contains" title="Static Semantics: Contains">8.5.1 SS: Contains</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-computedpropertycontains" title="Static Semantics: ComputedPropertyContains">8.5.2 SS: ComputedPropertyContains</a></li></ol></li><li>+<a href="syntax-directed-operations.html#sec-syntax-directed-operations-miscellaneous" title="Miscellaneous">8.6 Miscellaneous</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-runtime-semantics-instantiatefunctionobject" title="Runtime Semantics: InstantiateFunctionObject">8.6.1 RS: InstantiateFunctionObject</a></li><li>+<a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" title="Runtime Semantics: BindingInitialization">8.6.2 RS: BindingInitialization</a><ol class="toc"><li><a href="syntax-directed-operations.html#sec-initializeboundname" title="InitializeBoundName ( name, value, environment )">8.6.2.1 InitializeBoundName ( <var>name</var>, <var>value</var>, <var>environment</var> )</a></li></ol></li><li><a href="syntax-directed-operations.html#sec-runtime-semantics-iteratorbindinginitialization" title="Runtime Semantics: IteratorBindingInitialization">8.6.3 RS: IteratorBindingInitialization</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-assignmenttargettype" title="Static Semantics: AssignmentTargetType">8.6.4 SS: AssignmentTargetType</a></li><li><a href="syntax-directed-operations.html#sec-static-semantics-propname" title="Static Semantics: PropName">8.6.5 SS: PropName</a></li></ol></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-executable-code-and-execution-contexts" title="Executable Code and Execution Contexts">9 Executable Code and Execution Contexts</a><ol class="toc"><li>+<a href="executable-code-and-execution-contexts.html#sec-environment-records" title="Environment Records">9.1 Environment Records</a><ol class="toc"><li>+<a href="executable-code-and-execution-contexts.html#sec-the-environment-record-type-hierarchy" title="The Environment Record Type Hierarchy">9.1.1 The Environment Record Type Hierarchy</a><ol class="toc"><li>+<a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records" title="Declarative Environment Records">9.1.1.1 Declarative Environment Records</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-hasbinding-n" title="HasBinding ( N )">9.1.1.1.1 HasBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-createmutablebinding-n-d" title="CreateMutableBinding ( N, D )">9.1.1.1.2 CreateMutableBinding ( <var>N</var>, <var>D</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-createimmutablebinding-n-s" title="CreateImmutableBinding ( N, S )">9.1.1.1.3 CreateImmutableBinding ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-initializebinding-n-v" title="InitializeBinding ( N, V )">9.1.1.1.4 InitializeBinding ( <var>N</var>, <var>V</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-setmutablebinding-n-v-s" title="SetMutableBinding ( N, V, S )">9.1.1.1.5 SetMutableBinding ( <var>N</var>, <var>V</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-getbindingvalue-n-s" title="GetBindingValue ( N, S )">9.1.1.1.6 GetBindingValue ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-deletebinding-n" title="DeleteBinding ( N )">9.1.1.1.7 DeleteBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-hasthisbinding" title="HasThisBinding ( )">9.1.1.1.8 HasThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-hassuperbinding" title="HasSuperBinding ( )">9.1.1.1.9 HasSuperBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records-withbaseobject" title="WithBaseObject ( )">9.1.1.1.10 WithBaseObject ( )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-object-environment-records" title="Object Environment Records">9.1.1.2 Object Environment Records</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-hasbinding-n" title="HasBinding ( N )">9.1.1.2.1 HasBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-createmutablebinding-n-d" title="CreateMutableBinding ( N, D )">9.1.1.2.2 CreateMutableBinding ( <var>N</var>, <var>D</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-createimmutablebinding-n-s" title="CreateImmutableBinding ( N, S )">9.1.1.2.3 CreateImmutableBinding ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-initializebinding-n-v" title="InitializeBinding ( N, V )">9.1.1.2.4 InitializeBinding ( <var>N</var>, <var>V</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-setmutablebinding-n-v-s" title="SetMutableBinding ( N, V, S )">9.1.1.2.5 SetMutableBinding ( <var>N</var>, <var>V</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-getbindingvalue-n-s" title="GetBindingValue ( N, S )">9.1.1.2.6 GetBindingValue ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-deletebinding-n" title="DeleteBinding ( N )">9.1.1.2.7 DeleteBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-hasthisbinding" title="HasThisBinding ( )">9.1.1.2.8 HasThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-hassuperbinding" title="HasSuperBinding ( )">9.1.1.2.9 HasSuperBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-object-environment-records-withbaseobject" title="WithBaseObject ( )">9.1.1.2.10 WithBaseObject ( )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-function-environment-records" title="Function Environment Records">9.1.1.3 Function Environment Records</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-bindthisvalue" title="BindThisValue ( V )">9.1.1.3.1 BindThisValue ( <var>V</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-function-environment-records-hasthisbinding" title="HasThisBinding ( )">9.1.1.3.2 HasThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-function-environment-records-hassuperbinding" title="HasSuperBinding ( )">9.1.1.3.3 HasSuperBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-function-environment-records-getthisbinding" title="GetThisBinding ( )">9.1.1.3.4 GetThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-getsuperbase" title="GetSuperBase ( )">9.1.1.3.5 GetSuperBase ( )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-global-environment-records" title="Global Environment Records">9.1.1.4 Global Environment Records</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-hasbinding-n" title="HasBinding ( N )">9.1.1.4.1 HasBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-createmutablebinding-n-d" title="CreateMutableBinding ( N, D )">9.1.1.4.2 CreateMutableBinding ( <var>N</var>, <var>D</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-createimmutablebinding-n-s" title="CreateImmutableBinding ( N, S )">9.1.1.4.3 CreateImmutableBinding ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-initializebinding-n-v" title="InitializeBinding ( N, V )">9.1.1.4.4 InitializeBinding ( <var>N</var>, <var>V</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-setmutablebinding-n-v-s" title="SetMutableBinding ( N, V, S )">9.1.1.4.5 SetMutableBinding ( <var>N</var>, <var>V</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-getbindingvalue-n-s" title="GetBindingValue ( N, S )">9.1.1.4.6 GetBindingValue ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-deletebinding-n" title="DeleteBinding ( N )">9.1.1.4.7 DeleteBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-hasthisbinding" title="HasThisBinding ( )">9.1.1.4.8 HasThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-hassuperbinding" title="HasSuperBinding ( )">9.1.1.4.9 HasSuperBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-withbaseobject" title="WithBaseObject ( )">9.1.1.4.10 WithBaseObject ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-global-environment-records-getthisbinding" title="GetThisBinding ( )">9.1.1.4.11 GetThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hasvardeclaration" title="HasVarDeclaration ( N )">9.1.1.4.12 HasVarDeclaration ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-haslexicaldeclaration" title="HasLexicalDeclaration ( N )">9.1.1.4.13 HasLexicalDeclaration ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hasrestrictedglobalproperty" title="HasRestrictedGlobalProperty ( N )">9.1.1.4.14 HasRestrictedGlobalProperty ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-candeclareglobalvar" title="CanDeclareGlobalVar ( N )">9.1.1.4.15 CanDeclareGlobalVar ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-candeclareglobalfunction" title="CanDeclareGlobalFunction ( N )">9.1.1.4.16 CanDeclareGlobalFunction ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-createglobalvarbinding" title="CreateGlobalVarBinding ( N, D )">9.1.1.4.17 CreateGlobalVarBinding ( <var>N</var>, <var>D</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-createglobalfunctionbinding" title="CreateGlobalFunctionBinding ( N, V, D )">9.1.1.4.18 CreateGlobalFunctionBinding ( <var>N</var>, <var>V</var>, <var>D</var> )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-module-environment-records" title="Module Environment Records">9.1.1.5 Module Environment Records</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-module-environment-records-getbindingvalue-n-s" title="GetBindingValue ( N, S )">9.1.1.5.1 GetBindingValue ( <var>N</var>, <var>S</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-module-environment-records-deletebinding-n" title="DeleteBinding ( N )">9.1.1.5.2 DeleteBinding ( <var>N</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-module-environment-records-hasthisbinding" title="HasThisBinding ( )">9.1.1.5.3 HasThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-module-environment-records-getthisbinding" title="GetThisBinding ( )">9.1.1.5.4 GetThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-createimportbinding" title="CreateImportBinding ( N, M, N2 )">9.1.1.5.5 CreateImportBinding ( <var>N</var>, <var>M</var>, <var>N2</var> )</a></li></ol></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-environment-record-operations" title="Environment Record Operations">9.1.2 Environment Record Operations</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-getidentifierreference" title="GetIdentifierReference ( env, name, strict )">9.1.2.1 GetIdentifierReference ( <var>env</var>, <var>name</var>, <var>strict</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment" title="NewDeclarativeEnvironment ( E )">9.1.2.2 NewDeclarativeEnvironment ( <var>E</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-newobjectenvironment" title="NewObjectEnvironment ( O, W, E )">9.1.2.3 NewObjectEnvironment ( <var>O</var>, <var>W</var>, <var>E</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-newfunctionenvironment" title="NewFunctionEnvironment ( F, newTarget )">9.1.2.4 NewFunctionEnvironment ( <var>F</var>, <var>newTarget</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-newglobalenvironment" title="NewGlobalEnvironment ( G, thisValue )">9.1.2.5 NewGlobalEnvironment ( <var>G</var>, <var>thisValue</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-newmoduleenvironment" title="NewModuleEnvironment ( E )">9.1.2.6 NewModuleEnvironment ( <var>E</var> )</a></li></ol></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-privateenvironment-records" title="PrivateEnvironment Records">9.2 PrivateEnvironment Records</a><ol class="toc"><li>+<a href="executable-code-and-execution-contexts.html#sec-privateenvironment-record-operations" title="PrivateEnvironment Record Operations">9.2.1 PrivateEnvironment Record Operations</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-newprivateenvironment" title="NewPrivateEnvironment ( outerPrivateEnv )">9.2.1.1 NewPrivateEnvironment ( <var>outerPrivateEnv</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-resolve-private-identifier" title="ResolvePrivateIdentifier ( privateEnv, identifier )">9.2.1.2 ResolvePrivateIdentifier ( <var>privateEnv</var>, <var>identifier</var> )</a></li></ol></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-code-realms" title="Realms">9.3 Realms</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-initializehostdefinedrealm" title="InitializeHostDefinedRealm ( )">9.3.1 InitializeHostDefinedRealm ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-createintrinsics" title="CreateIntrinsics ( realmRec )">9.3.2 CreateIntrinsics ( <var>realmRec</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-setdefaultglobalbindings" title="SetDefaultGlobalBindings ( realmRec )">9.3.3 SetDefaultGlobalBindings ( <var>realmRec</var> )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-execution-contexts" title="Execution Contexts">9.4 Execution Contexts</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-getactivescriptormodule" title="GetActiveScriptOrModule ( )">9.4.1 GetActiveScriptOrModule ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-resolvebinding" title="ResolveBinding ( name [ , env ] )">9.4.2 ResolveBinding ( <var>name</var> [ , <var>env</var> ] )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-getthisenvironment" title="GetThisEnvironment ( )">9.4.3 GetThisEnvironment ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-resolvethisbinding" title="ResolveThisBinding ( )">9.4.4 ResolveThisBinding ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-getnewtarget" title="GetNewTarget ( )">9.4.5 GetNewTarget ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-getglobalobject" title="GetGlobalObject ( )">9.4.6 GetGlobalObject ( )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-jobs" title="Jobs and Host Operations to Enqueue Jobs">9.5 Jobs and Host Operations to Enqueue Jobs</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-jobcallback-records" title="JobCallback Records">9.5.1 JobCallback Records</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hostmakejobcallback" title="HostMakeJobCallback ( callback )">9.5.2 HostMakeJobCallback ( <var>callback</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hostcalljobcallback" title="HostCallJobCallback ( jobCallback, V, argumentsList )">9.5.3 HostCallJobCallback ( <var>jobCallback</var>, <var>V</var>, <var>argumentsList</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hostenqueuegenericjob" title="HostEnqueueGenericJob ( job, realm )">9.5.4 HostEnqueueGenericJob ( <var>job</var>, <var>realm</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hostenqueuepromisejob" title="HostEnqueuePromiseJob ( job, realm )">9.5.5 HostEnqueuePromiseJob ( <var>job</var>, <var>realm</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-hostenqueuetimeoutjob" title="HostEnqueueTimeoutJob ( timeoutJob, realm, milliseconds )">9.5.6 HostEnqueueTimeoutJob ( <var>timeoutJob</var>, <var>realm</var>, <var>milliseconds</var> )</a></li></ol></li><li>+<a href="executable-code-and-execution-contexts.html#sec-agents" title="Agents">9.6 Agents</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-agentsignifier" title="AgentSignifier ( )">9.6.1 AgentSignifier ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-agentcansuspend" title="AgentCanSuspend ( )">9.6.2 AgentCanSuspend ( )</a></li></ol></li><li><a href="executable-code-and-execution-contexts.html#sec-agent-clusters" title="Agent Clusters">9.7 Agent Clusters</a></li><li><a href="executable-code-and-execution-contexts.html#sec-forward-progress" title="Forward Progress">9.8 Forward Progress</a></li><li>+<a href="executable-code-and-execution-contexts.html#sec-weakref-processing-model" title="Processing Model of WeakRef and FinalizationRegistry Targets">9.9 Processing Model of WeakRef and FinalizationRegistry Targets</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-weakref-invariants" title="Objectives">9.9.1 Objectives</a></li><li><a href="executable-code-and-execution-contexts.html#sec-liveness" title="Liveness">9.9.2 Liveness</a></li><li><a href="executable-code-and-execution-contexts.html#sec-weakref-execution" title="Execution">9.9.3 Execution</a></li><li>+<a href="executable-code-and-execution-contexts.html#sec-weakref-host-hooks" title="Host Hooks">9.9.4 Host Hooks</a><ol class="toc"><li><a href="executable-code-and-execution-contexts.html#sec-host-cleanup-finalization-registry" title="HostEnqueueFinalizationRegistryCleanupJob ( finalizationRegistry )">9.9.4.1 HostEnqueueFinalizationRegistryCleanupJob ( <var>finalizationRegistry</var> )</a></li></ol></li></ol></li><li><a href="executable-code-and-execution-contexts.html#sec-clear-kept-objects" title="ClearKeptObjects ( )">9.10 ClearKeptObjects ( )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-addtokeptobjects" title="AddToKeptObjects ( value )">9.11 AddToKeptObjects ( <var>value</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-cleanup-finalization-registry" title="CleanupFinalizationRegistry ( finalizationRegistry )">9.12 CleanupFinalizationRegistry ( <var>finalizationRegistry</var> )</a></li><li><a href="executable-code-and-execution-contexts.html#sec-canbeheldweakly" title="CanBeHeldWeakly ( v )">9.13 CanBeHeldWeakly ( <var>v</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-and-exotic-objects-behaviours" title="Ordinary and Exotic Objects Behaviours">10 Ordinary and Exotic Objects Behaviours</a><ol class="toc"><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots" title="Ordinary Object Internal Methods and Internal Slots">10.1 Ordinary Object Internal Methods and Internal Slots</a><ol class="toc"><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-getprototypeof" title="[[GetPrototypeOf]] ( )">10.1.1 <var class="field">[[GetPrototypeOf]]</var> ( )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarygetprototypeof" title="OrdinaryGetPrototypeOf ( O )">10.1.1.1 OrdinaryGetPrototypeOf ( <var>O</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-setprototypeof-v" title="[[SetPrototypeOf]] ( V )">10.1.2 <var class="field">[[SetPrototypeOf]]</var> ( <var>V</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarysetprototypeof" title="OrdinarySetPrototypeOf ( O, V )">10.1.2.1 OrdinarySetPrototypeOf ( <var>O</var>, <var>V</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-isextensible" title="[[IsExtensible]] ( )">10.1.3 <var class="field">[[IsExtensible]]</var> ( )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryisextensible" title="OrdinaryIsExtensible ( O )">10.1.3.1 OrdinaryIsExtensible ( <var>O</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-preventextensions" title="[[PreventExtensions]] ( )">10.1.4 <var class="field">[[PreventExtensions]]</var> ( )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarypreventextensions" title="OrdinaryPreventExtensions ( O )">10.1.4.1 OrdinaryPreventExtensions ( <var>O</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-getownproperty-p" title="[[GetOwnProperty]] ( P )">10.1.5 <var class="field">[[GetOwnProperty]]</var> ( <var>P</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarygetownproperty" title="OrdinaryGetOwnProperty ( O, P )">10.1.5.1 OrdinaryGetOwnProperty ( <var>O</var>, <var>P</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-defineownproperty-p-desc" title="[[DefineOwnProperty]] ( P, Desc )">10.1.6 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarydefineownproperty" title="OrdinaryDefineOwnProperty ( O, P, Desc )">10.1.6.1 OrdinaryDefineOwnProperty ( <var>O</var>, <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-iscompatiblepropertydescriptor" title="IsCompatiblePropertyDescriptor ( Extensible, Desc, Current )">10.1.6.2 IsCompatiblePropertyDescriptor ( <var>Extensible</var>, <var>Desc</var>, <var>Current</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-validateandapplypropertydescriptor" title="ValidateAndApplyPropertyDescriptor ( O, P, extensible, Desc, current )">10.1.6.3 ValidateAndApplyPropertyDescriptor ( <var>O</var>, <var>P</var>, <var>extensible</var>, <var>Desc</var>, <var>current</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-hasproperty-p" title="[[HasProperty]] ( P )">10.1.7 <var class="field">[[HasProperty]]</var> ( <var>P</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryhasproperty" title="OrdinaryHasProperty ( O, P )">10.1.7.1 OrdinaryHasProperty ( <var>O</var>, <var>P</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-get-p-receiver" title="[[Get]] ( P, Receiver )">10.1.8 <var class="field">[[Get]]</var> ( <var>P</var>, <var>Receiver</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryget" title="OrdinaryGet ( O, P, Receiver )">10.1.8.1 OrdinaryGet ( <var>O</var>, <var>P</var>, <var>Receiver</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-set-p-v-receiver" title="[[Set]] ( P, V, Receiver )">10.1.9 <var class="field">[[Set]]</var> ( <var>P</var>, <var>V</var>, <var>Receiver</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryset" title="OrdinarySet ( O, P, V, Receiver )">10.1.9.1 OrdinarySet ( <var>O</var>, <var>P</var>, <var>V</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarysetwithowndescriptor" title="OrdinarySetWithOwnDescriptor ( O, P, V, Receiver, ownDesc )">10.1.9.2 OrdinarySetWithOwnDescriptor ( <var>O</var>, <var>P</var>, <var>V</var>, <var>Receiver</var>, <var>ownDesc</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-delete-p" title="[[Delete]] ( P )">10.1.10 <var class="field">[[Delete]]</var> ( <var>P</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarydelete" title="OrdinaryDelete ( O, P )">10.1.10.1 OrdinaryDelete ( <var>O</var>, <var>P</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinary-object-internal-methods-and-internal-slots-ownpropertykeys" title="[[OwnPropertyKeys]] ( )">10.1.11 <var class="field">[[OwnPropertyKeys]]</var> ( )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryownpropertykeys" title="OrdinaryOwnPropertyKeys ( O )">10.1.11.1 OrdinaryOwnPropertyKeys ( <var>O</var> )</a></li></ol></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryobjectcreate" title="OrdinaryObjectCreate ( proto [ , additionalInternalSlotsList ] )">10.1.12 OrdinaryObjectCreate ( <var>proto</var> [ , <var>additionalInternalSlotsList</var> ] )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarycreatefromconstructor" title="OrdinaryCreateFromConstructor ( constructor, intrinsicDefaultProto [ , internalSlotsList ] )">10.1.13 OrdinaryCreateFromConstructor ( <var>constructor</var>, <var>intrinsicDefaultProto</var> [ , <var>internalSlotsList</var> ] )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-getprototypefromconstructor" title="GetPrototypeFromConstructor ( constructor, intrinsicDefaultProto )">10.1.14 GetPrototypeFromConstructor ( <var>constructor</var>, <var>intrinsicDefaultProto</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-requireinternalslot" title="RequireInternalSlot ( O, internalSlot )">10.1.15 RequireInternalSlot ( <var>O</var>, <var>internalSlot</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ecmascript-function-objects" title="ECMAScript Function Objects">10.2 ECMAScript Function Objects</a><ol class="toc"><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-ecmascript-function-objects-call-thisargument-argumentslist" title="[[Call]] ( thisArgument, argumentsList )">10.2.1 <var class="field">[[Call]]</var> ( <var>thisArgument</var>, <var>argumentsList</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-prepareforordinarycall" title="PrepareForOrdinaryCall ( F, newTarget )">10.2.1.1 PrepareForOrdinaryCall ( <var>F</var>, <var>newTarget</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarycallbindthis" title="OrdinaryCallBindThis ( F, calleeContext, thisArgument )">10.2.1.2 OrdinaryCallBindThis ( <var>F</var>, <var>calleeContext</var>, <var>thisArgument</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-runtime-semantics-evaluatebody" title="Runtime Semantics: EvaluateBody">10.2.1.3 RS: EvaluateBody</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinarycallevaluatebody" title="OrdinaryCallEvaluateBody ( F, argumentsList )">10.2.1.4 OrdinaryCallEvaluateBody ( <var>F</var>, <var>argumentsList</var> )</a></li></ol></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ecmascript-function-objects-construct-argumentslist-newtarget" title="[[Construct]] ( argumentsList, newTarget )">10.2.2 <var class="field">[[Construct]]</var> ( <var>argumentsList</var>, <var>newTarget</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryfunctioncreate" title="OrdinaryFunctionCreate ( functionPrototype, sourceText, ParameterList, Body, thisMode, env, privateEnv )">10.2.3 OrdinaryFunctionCreate ( <var>functionPrototype</var>, <var>sourceText</var>, <var>ParameterList</var>, <var>Body</var>, <var>thisMode</var>, <var>env</var>, <var>privateEnv</var> )</a></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-addrestrictedfunctionproperties" title="AddRestrictedFunctionProperties ( F, realm )">10.2.4 AddRestrictedFunctionProperties ( <var>F</var>, <var>realm</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-%throwtypeerror%" title="%ThrowTypeError% ( )">10.2.4.1 %ThrowTypeError% ( )</a></li></ol></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-makeconstructor" title="MakeConstructor ( F [ , writablePrototype [ , prototype ] ] )">10.2.5 MakeConstructor ( <var>F</var> [ , <var>writablePrototype</var> [ , <var>prototype</var> ] ] )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-makeclassconstructor" title="MakeClassConstructor ( F )">10.2.6 MakeClassConstructor ( <var>F</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-makemethod" title="MakeMethod ( F, homeObject )">10.2.7 MakeMethod ( <var>F</var>, <var>homeObject</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-definemethodproperty" title="DefineMethodProperty ( homeObject, key, closure, enumerable )">10.2.8 DefineMethodProperty ( <var>homeObject</var>, <var>key</var>, <var>closure</var>, <var>enumerable</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-setfunctionname" title="SetFunctionName ( F, name [ , prefix ] )">10.2.9 SetFunctionName ( <var>F</var>, <var>name</var> [ , <var>prefix</var> ] )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-setfunctionlength" title="SetFunctionLength ( F, length )">10.2.10 SetFunctionLength ( <var>F</var>, <var>length</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-functiondeclarationinstantiation" title="FunctionDeclarationInstantiation ( func, argumentsList )">10.2.11 FunctionDeclarationInstantiation ( <var>func</var>, <var>argumentsList</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-built-in-function-objects" title="Built-in Function Objects">10.3 Built-in Function Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-built-in-function-objects-call-thisargument-argumentslist" title="[[Call]] ( thisArgument, argumentsList )">10.3.1 <var class="field">[[Call]]</var> ( <var>thisArgument</var>, <var>argumentsList</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-built-in-function-objects-construct-argumentslist-newtarget" title="[[Construct]] ( argumentsList, newTarget )">10.3.2 <var class="field">[[Construct]]</var> ( <var>argumentsList</var>, <var>newTarget</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-builtincallorconstruct" title="BuiltinCallOrConstruct ( F, thisArgument, argumentsList, newTarget )">10.3.3 BuiltinCallOrConstruct ( <var>F</var>, <var>thisArgument</var>, <var>argumentsList</var>, <var>newTarget</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-createbuiltinfunction" title="CreateBuiltinFunction ( behaviour, length, name, additionalInternalSlotsList [ , realm [ , prototype [ , prefix ] ] ] )">10.3.4 CreateBuiltinFunction ( <var>behaviour</var>, <var>length</var>, <var>name</var>, <var>additionalInternalSlotsList</var> [ , <var>realm</var> [ , <var>prototype</var> [ , <var>prefix</var> ] ] ] )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-built-in-exotic-object-internal-methods-and-slots" title="Built-in Exotic Object Internal Methods and Slots">10.4 Built-in Exotic Object Internal Methods and Slots</a><ol class="toc"><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-bound-function-exotic-objects" title="Bound Function Exotic Objects">10.4.1 Bound Function Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-bound-function-exotic-objects-call-thisargument-argumentslist" title="[[Call]] ( thisArgument, argumentsList )">10.4.1.1 <var class="field">[[Call]]</var> ( <var>thisArgument</var>, <var>argumentsList</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-bound-function-exotic-objects-construct-argumentslist-newtarget" title="[[Construct]] ( argumentsList, newTarget )">10.4.1.2 <var class="field">[[Construct]]</var> ( <var>argumentsList</var>, <var>newTarget</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-boundfunctioncreate" title="BoundFunctionCreate ( targetFunction, boundThis, boundArgs )">10.4.1.3 BoundFunctionCreate ( <var>targetFunction</var>, <var>boundThis</var>, <var>boundArgs</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-array-exotic-objects" title="Array Exotic Objects">10.4.2 Array Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-array-exotic-objects-defineownproperty-p-desc" title="[[DefineOwnProperty]] ( P, Desc )">10.4.2.1 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arraycreate" title="ArrayCreate ( length [ , proto ] )">10.4.2.2 ArrayCreate ( <var>length</var> [ , <var>proto</var> ] )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arrayspeciescreate" title="ArraySpeciesCreate ( originalArray, length )">10.4.2.3 ArraySpeciesCreate ( <var>originalArray</var>, <var>length</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arraysetlength" title="ArraySetLength ( A, Desc )">10.4.2.4 ArraySetLength ( <var>A</var>, <var>Desc</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-string-exotic-objects" title="String Exotic Objects">10.4.3 String Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-string-exotic-objects-getownproperty-p" title="[[GetOwnProperty]] ( P )">10.4.3.1 <var class="field">[[GetOwnProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-string-exotic-objects-defineownproperty-p-desc" title="[[DefineOwnProperty]] ( P, Desc )">10.4.3.2 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-string-exotic-objects-ownpropertykeys" title="[[OwnPropertyKeys]] ( )">10.4.3.3 <var class="field">[[OwnPropertyKeys]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-stringcreate" title="StringCreate ( value, prototype )">10.4.3.4 StringCreate ( <var>value</var>, <var>prototype</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-stringgetownproperty" title="StringGetOwnProperty ( S, P )">10.4.3.5 StringGetOwnProperty ( <var>S</var>, <var>P</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-arguments-exotic-objects" title="Arguments Exotic Objects">10.4.4 Arguments Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arguments-exotic-objects-getownproperty-p" title="[[GetOwnProperty]] ( P )">10.4.4.1 <var class="field">[[GetOwnProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arguments-exotic-objects-defineownproperty-p-desc" title="[[DefineOwnProperty]] ( P, Desc )">10.4.4.2 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arguments-exotic-objects-get-p-receiver" title="[[Get]] ( P, Receiver )">10.4.4.3 <var class="field">[[Get]]</var> ( <var>P</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arguments-exotic-objects-set-p-v-receiver" title="[[Set]] ( P, V, Receiver )">10.4.4.4 <var class="field">[[Set]]</var> ( <var>P</var>, <var>V</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-arguments-exotic-objects-delete-p" title="[[Delete]] ( P )">10.4.4.5 <var class="field">[[Delete]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-createunmappedargumentsobject" title="CreateUnmappedArgumentsObject ( argumentsList )">10.4.4.6 CreateUnmappedArgumentsObject ( <var>argumentsList</var> )</a></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-createmappedargumentsobject" title="CreateMappedArgumentsObject ( func, formals, argumentsList, env )">10.4.4.7 CreateMappedArgumentsObject ( <var>func</var>, <var>formals</var>, <var>argumentsList</var>, <var>env</var> )</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-makearggetter" title="MakeArgGetter ( name, env )">10.4.4.7.1 MakeArgGetter ( <var>name</var>, <var>env</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-makeargsetter" title="MakeArgSetter ( name, env )">10.4.4.7.2 MakeArgSetter ( <var>name</var>, <var>env</var> )</a></li></ol></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-exotic-objects" title="TypedArray Exotic Objects">10.4.5 TypedArray Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-preventextensions" title="[[PreventExtensions]] ( )">10.4.5.1 <var class="field">[[PreventExtensions]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-getownproperty" title="[[GetOwnProperty]] ( P )">10.4.5.2 <var class="field">[[GetOwnProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-hasproperty" title="[[HasProperty]] ( P )">10.4.5.3 <var class="field">[[HasProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-defineownproperty" title="[[DefineOwnProperty]] ( P, Desc )">10.4.5.4 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-get" title="[[Get]] ( P, Receiver )">10.4.5.5 <var class="field">[[Get]]</var> ( <var>P</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-set" title="[[Set]] ( P, V, Receiver )">10.4.5.6 <var class="field">[[Set]]</var> ( <var>P</var>, <var>V</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-delete" title="[[Delete]] ( P )">10.4.5.7 <var class="field">[[Delete]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-ownpropertykeys" title="[[OwnPropertyKeys]] ( )">10.4.5.8 <var class="field">[[OwnPropertyKeys]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarray-with-buffer-witness-records" title="TypedArray With Buffer Witness Records">10.4.5.9 TypedArray With Buffer Witness Records</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-maketypedarraywithbufferwitnessrecord" title="MakeTypedArrayWithBufferWitnessRecord ( obj, order )">10.4.5.10 MakeTypedArrayWithBufferWitnessRecord ( <var>obj</var>, <var>order</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarraycreate" title="TypedArrayCreate ( prototype )">10.4.5.11 TypedArrayCreate ( <var>prototype</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarraybytelength" title="TypedArrayByteLength ( taRecord )">10.4.5.12 TypedArrayByteLength ( <var>taRecord</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarraylength" title="TypedArrayLength ( taRecord )">10.4.5.13 TypedArrayLength ( <var>taRecord</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-istypedarrayoutofbounds" title="IsTypedArrayOutOfBounds ( taRecord )">10.4.5.14 IsTypedArrayOutOfBounds ( <var>taRecord</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-istypedarrayfixedlength" title="IsTypedArrayFixedLength ( O )">10.4.5.15 IsTypedArrayFixedLength ( <var>O</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-isvalidintegerindex" title="IsValidIntegerIndex ( O, index )">10.4.5.16 IsValidIntegerIndex ( <var>O</var>, <var>index</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarraygetelement" title="TypedArrayGetElement ( O, index )">10.4.5.17 TypedArrayGetElement ( <var>O</var>, <var>index</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-typedarraysetelement" title="TypedArraySetElement ( O, index, value )">10.4.5.18 TypedArraySetElement ( <var>O</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-isarraybufferviewoutofbounds" title="IsArrayBufferViewOutOfBounds ( O )">10.4.5.19 IsArrayBufferViewOutOfBounds ( <var>O</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects" title="Module Namespace Exotic Objects">10.4.6 Module Namespace Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-getprototypeof" title="[[GetPrototypeOf]] ( )">10.4.6.1 <var class="field">[[GetPrototypeOf]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-setprototypeof-v" title="[[SetPrototypeOf]] ( V )">10.4.6.2 <var class="field">[[SetPrototypeOf]]</var> ( <var>V</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-isextensible" title="[[IsExtensible]] ( )">10.4.6.3 <var class="field">[[IsExtensible]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-preventextensions" title="[[PreventExtensions]] ( )">10.4.6.4 <var class="field">[[PreventExtensions]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-getownproperty-p" title="[[GetOwnProperty]] ( P )">10.4.6.5 <var class="field">[[GetOwnProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-defineownproperty-p-desc" title="[[DefineOwnProperty]] ( P, Desc )">10.4.6.6 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-hasproperty-p" title="[[HasProperty]] ( P )">10.4.6.7 <var class="field">[[HasProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-get-p-receiver" title="[[Get]] ( P, Receiver )">10.4.6.8 <var class="field">[[Get]]</var> ( <var>P</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-set-p-v-receiver" title="[[Set]] ( P, V, Receiver )">10.4.6.9 <var class="field">[[Set]]</var> ( <var>P</var>, <var>V</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-delete-p" title="[[Delete]] ( P )">10.4.6.10 <var class="field">[[Delete]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-module-namespace-exotic-objects-ownpropertykeys" title="[[OwnPropertyKeys]] ( )">10.4.6.11 <var class="field">[[OwnPropertyKeys]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-modulenamespacecreate" title="ModuleNamespaceCreate ( module, exports )">10.4.6.12 ModuleNamespaceCreate ( <var>module</var>, <var>exports</var> )</a></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-immutable-prototype-exotic-objects" title="Immutable Prototype Exotic Objects">10.4.7 Immutable Prototype Exotic Objects</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-immutable-prototype-exotic-objects-setprototypeof-v" title="[[SetPrototypeOf]] ( V )">10.4.7.1 <var class="field">[[SetPrototypeOf]]</var> ( <var>V</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-set-immutable-prototype" title="SetImmutablePrototype ( O, V )">10.4.7.2 SetImmutablePrototype ( <var>O</var>, <var>V</var> )</a></li></ol></li></ol></li><li>+<a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots" title="Proxy Object Internal Methods and Internal Slots">10.5 Proxy Object Internal Methods and Internal Slots</a><ol class="toc"><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof" title="[[GetPrototypeOf]] ( )">10.5.1 <var class="field">[[GetPrototypeOf]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v" title="[[SetPrototypeOf]] ( V )">10.5.2 <var class="field">[[SetPrototypeOf]]</var> ( <var>V</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-isextensible" title="[[IsExtensible]] ( )">10.5.3 <var class="field">[[IsExtensible]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-preventextensions" title="[[PreventExtensions]] ( )">10.5.4 <var class="field">[[PreventExtensions]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p" title="[[GetOwnProperty]] ( P )">10.5.5 <var class="field">[[GetOwnProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc" title="[[DefineOwnProperty]] ( P, Desc )">10.5.6 <var class="field">[[DefineOwnProperty]]</var> ( <var>P</var>, <var>Desc</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p" title="[[HasProperty]] ( P )">10.5.7 <var class="field">[[HasProperty]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver" title="[[Get]] ( P, Receiver )">10.5.8 <var class="field">[[Get]]</var> ( <var>P</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-set-p-v-receiver" title="[[Set]] ( P, V, Receiver )">10.5.9 <var class="field">[[Set]]</var> ( <var>P</var>, <var>V</var>, <var>Receiver</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-delete-p" title="[[Delete]] ( P )">10.5.10 <var class="field">[[Delete]]</var> ( <var>P</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys" title="[[OwnPropertyKeys]] ( )">10.5.11 <var class="field">[[OwnPropertyKeys]]</var> ( )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-call-thisargument-argumentslist" title="[[Call]] ( thisArgument, argumentsList )">10.5.12 <var class="field">[[Call]]</var> ( <var>thisArgument</var>, <var>argumentsList</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-construct-argumentslist-newtarget" title="[[Construct]] ( argumentsList, newTarget )">10.5.13 <var class="field">[[Construct]]</var> ( <var>argumentsList</var>, <var>newTarget</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-validatenonrevokedproxy" title="ValidateNonRevokedProxy ( proxy )">10.5.14 ValidateNonRevokedProxy ( <var>proxy</var> )</a></li><li><a href="ordinary-and-exotic-objects-behaviours.html#sec-proxycreate" title="ProxyCreate ( target, handler )">10.5.15 ProxyCreate ( <var>target</var>, <var>handler</var> )</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-source-code.html#sec-ecmascript-language-source-code" title="ECMAScript Language: Source Text">11 ECMAScript Language: Source Text</a><ol class="toc"><li>+<a href="ecmascript-language-source-code.html#sec-source-text" title="Source Text">11.1 Source Text</a><ol class="toc"><li><a href="ecmascript-language-source-code.html#sec-utf16encodecodepoint" title="Static Semantics: UTF16EncodeCodePoint ( cp )">11.1.1 SS: UTF16EncodeCodePoint ( <var>cp</var> )</a></li><li><a href="ecmascript-language-source-code.html#sec-codepointstostring" title="Static Semantics: CodePointsToString ( text )">11.1.2 SS: CodePointsToString ( <var>text</var> )</a></li><li><a href="ecmascript-language-source-code.html#sec-utf16decodesurrogatepair" title="Static Semantics: UTF16SurrogatePairToCodePoint ( lead, trail )">11.1.3 SS: UTF16SurrogatePairToCodePoint ( <var>lead</var>, <var>trail</var> )</a></li><li><a href="ecmascript-language-source-code.html#sec-codepointat" title="Static Semantics: CodePointAt ( string, position )">11.1.4 SS: CodePointAt ( <var>string</var>, <var>position</var> )</a></li><li><a href="ecmascript-language-source-code.html#sec-stringtocodepoints" title="Static Semantics: StringToCodePoints ( string )">11.1.5 SS: StringToCodePoints ( <var>string</var> )</a></li><li><a href="ecmascript-language-source-code.html#sec-parsetext" title="Static Semantics: ParseText ( sourceText, goalSymbol )">11.1.6 SS: ParseText ( <var>sourceText</var>, <var>goalSymbol</var> )</a></li></ol></li><li>+<a href="ecmascript-language-source-code.html#sec-types-of-source-code" title="Types of Source Code">11.2 Types of Source Code</a><ol class="toc"><li><a href="ecmascript-language-source-code.html#sec-directive-prologues-and-the-use-strict-directive" title="Directive Prologues and the Use Strict Directive">11.2.1 Directive Prologues and the Use Strict Directive</a></li><li>+<a href="ecmascript-language-source-code.html#sec-strict-mode-code" title="Strict Mode Code">11.2.2 Strict Mode Code</a><ol class="toc"><li><a href="ecmascript-language-source-code.html#sec-isstrict" title="Static Semantics: IsStrict ( node )">11.2.2.1 SS: IsStrict ( <var>node</var> )</a></li></ol></li><li><a href="ecmascript-language-source-code.html#sec-non-ecmascript-functions" title="Non-ECMAScript Functions">11.2.3 Non-ECMAScript Functions</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-ecmascript-language-lexical-grammar" title="ECMAScript Language: Lexical Grammar">12 ECMAScript Language: Lexical Grammar</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-unicode-format-control-characters" title="Unicode Format-Control Characters">12.1 Unicode Format-Control Characters</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-white-space" title="White Space">12.2 White Space</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-line-terminators" title="Line Terminators">12.3 Line Terminators</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-comments" title="Comments">12.4 Comments</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-hashbang" title="Hashbang Comments">12.5 Hashbang Comments</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-tokens" title="Tokens">12.6 Tokens</a></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-names-and-keywords" title="Names and Keywords">12.7 Names and Keywords</a><ol class="toc"><li>+<a href="ecmascript-language-lexical-grammar.html#sec-identifier-names" title="Identifier Names">12.7.1 Identifier Names</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-identifier-names-static-semantics-early-errors" title="Static Semantics: Early Errors">12.7.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-identifiercodepoints" title="Static Semantics: IdentifierCodePoints">12.7.1.2 SS: IdentifierCodePoints</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-identifiercodepoint" title="Static Semantics: IdentifierCodePoint">12.7.1.3 SS: IdentifierCodePoint</a></li></ol></li><li><a href="ecmascript-language-lexical-grammar.html#sec-keywords-and-reserved-words" title="Keywords and Reserved Words">12.7.2 Keywords and Reserved Words</a></li></ol></li><li><a href="ecmascript-language-lexical-grammar.html#sec-punctuators" title="Punctuators">12.8 Punctuators</a></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-ecmascript-language-lexical-grammar-literals" title="Literals">12.9 Literals</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-null-literals" title="Null Literals">12.9.1 Null Literals</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-boolean-literals" title="Boolean Literals">12.9.2 Boolean Literals</a></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-literals-numeric-literals" title="Numeric Literals">12.9.3 Numeric Literals</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-numeric-literals-early-errors" title="Static Semantics: Early Errors">12.9.3.1 SS: Early Errors</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-static-semantics-mv" title="Static Semantics: MV">12.9.3.2 SS: MV</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-numericvalue" title="Static Semantics: NumericValue">12.9.3.3 SS: NumericValue</a></li></ol></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-literals-string-literals" title="String Literals">12.9.4 String Literals</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-string-literals-early-errors" title="Static Semantics: Early Errors">12.9.4.1 SS: Early Errors</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-static-semantics-sv" title="Static Semantics: SV">12.9.4.2 SS: SV</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-string-literals-static-semantics-mv" title="Static Semantics: MV">12.9.4.3 SS: MV</a></li></ol></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-literals-regular-expression-literals" title="Regular Expression Literals">12.9.5 Regular Expression Literals</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-static-semantics-bodytext" title="Static Semantics: BodyText">12.9.5.1 SS: BodyText</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-static-semantics-flagtext" title="Static Semantics: FlagText">12.9.5.2 SS: FlagText</a></li></ol></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-template-literal-lexical-components" title="Template Literal Lexical Components">12.9.6 Template Literal Lexical Components</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-static-semantics-tv" title="Static Semantics: TV">12.9.6.1 SS: TV</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-static-semantics-trv" title="Static Semantics: TRV">12.9.6.2 SS: TRV</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-automatic-semicolon-insertion" title="Automatic Semicolon Insertion">12.10 Automatic Semicolon Insertion</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-rules-of-automatic-semicolon-insertion" title="Rules of Automatic Semicolon Insertion">12.10.1 Rules of Automatic Semicolon Insertion</a></li><li><a href="ecmascript-language-lexical-grammar.html#sec-examples-of-automatic-semicolon-insertion" title="Examples of Automatic Semicolon Insertion">12.10.2 Examples of Automatic Semicolon Insertion</a></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-interesting-cases-of-automatic-semicolon-insertion" title="Interesting Cases of Automatic Semicolon Insertion">12.10.3 Interesting Cases of Automatic Semicolon Insertion</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-asi-interesting-cases-in-statement-lists" title="Interesting Cases of Automatic Semicolon Insertion in Statement Lists">12.10.3.1 Interesting Cases of Automatic Semicolon Insertion in Statement Lists</a></li><li>+<a href="ecmascript-language-lexical-grammar.html#sec-asi-cases-with-no-lineterminator-here" title="Cases of Automatic Semicolon Insertion and “[no LineTerminator here]”">12.10.3.2 Cases of Automatic Semicolon Insertion and “[no <emu-nt>LineTerminator</emu-nt> here]”</a><ol class="toc"><li><a href="ecmascript-language-lexical-grammar.html#sec-no-lineterminator-here-automatic-semicolon-insertion-list" title="List of Grammar Productions with Optional Operands and “[no LineTerminator here]”">12.10.3.2.1 List of Grammar Productions with Optional Operands and “[no <emu-nt>LineTerminator</emu-nt> here]”</a></li></ol></li></ol></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-ecmascript-language-expressions" title="ECMAScript Language: Expressions">13 ECMAScript Language: Expressions</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-identifiers" title="Identifiers">13.1 Identifiers</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-identifiers-static-semantics-early-errors" title="Static Semantics: Early Errors">13.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue" title="Static Semantics: StringValue">13.1.2 SS: StringValue</a></li><li><a href="ecmascript-language-expressions.html#sec-identifiers-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.1.3 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-primary-expression" title="Primary Expression">13.2 Primary Expression</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-this-keyword" title="The this Keyword">13.2.1 The <code>this</code> Keyword</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-this-keyword-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.1.1 RS: Evaluation</a></li></ol></li><li><a href="ecmascript-language-expressions.html#sec-identifier-reference" title="Identifier Reference">13.2.2 Identifier Reference</a></li><li>+<a href="ecmascript-language-expressions.html#sec-primary-expression-literals" title="Literals">13.2.3 Literals</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-literals-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.3.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-array-initializer" title="Array Initializer">13.2.4 Array Initializer</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-arrayaccumulation" title="Runtime Semantics: ArrayAccumulation">13.2.4.1 RS: ArrayAccumulation</a></li><li><a href="ecmascript-language-expressions.html#sec-array-initializer-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.4.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-object-initializer" title="Object Initializer">13.2.5 Object Initializer</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-object-initializer-static-semantics-early-errors" title="Static Semantics: Early Errors">13.2.5.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-static-semantics-iscomputedpropertykey" title="Static Semantics: IsComputedPropertyKey">13.2.5.2 SS: IsComputedPropertyKey</a></li><li><a href="ecmascript-language-expressions.html#sec-static-semantics-propertynamelist" title="Static Semantics: PropertyNameList">13.2.5.3 SS: PropertyNameList</a></li><li><a href="ecmascript-language-expressions.html#sec-object-initializer-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.5.4 RS: Evaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-propertydefinitionevaluation" title="Runtime Semantics: PropertyDefinitionEvaluation">13.2.5.5 RS: PropertyDefinitionEvaluation</a></li></ol></li><li><a href="ecmascript-language-expressions.html#sec-function-defining-expressions" title="Function Defining Expressions">13.2.6 Function Defining Expressions</a></li><li>+<a href="ecmascript-language-expressions.html#sec-primary-expression-regular-expression-literals" title="Regular Expression Literals">13.2.7 Regular Expression Literals</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-primary-expression-regular-expression-literals-static-semantics-early-errors" title="Static Semantics: Early Errors">13.2.7.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-isvalidregularexpressionliteral" title="Static Semantics: IsValidRegularExpressionLiteral ( literal )">13.2.7.2 SS: IsValidRegularExpressionLiteral ( <var>literal</var> )</a></li><li><a href="ecmascript-language-expressions.html#sec-regular-expression-literals-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.7.3 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-template-literals" title="Template Literals">13.2.8 Template Literals</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-static-semantics-template-early-errors" title="Static Semantics: Early Errors">13.2.8.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-static-semantics-templatestrings" title="Static Semantics: TemplateStrings">13.2.8.2 SS: TemplateStrings</a></li><li><a href="ecmascript-language-expressions.html#sec-templatestring" title="Static Semantics: TemplateString ( templateToken, raw )">13.2.8.3 SS: TemplateString ( <var>templateToken</var>, <var>raw</var> )</a></li><li><a href="ecmascript-language-expressions.html#sec-gettemplateobject" title="GetTemplateObject ( templateLiteral )">13.2.8.4 GetTemplateObject ( <var>templateLiteral</var> )</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-substitutionevaluation" title="Runtime Semantics: SubstitutionEvaluation">13.2.8.5 RS: SubstitutionEvaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-template-literals-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.8.6 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-grouping-operator" title="The Grouping Operator">13.2.9 The Grouping Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-grouping-operator-static-semantics-early-errors" title="Static Semantics: Early Errors">13.2.9.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-grouping-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.2.9.2 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-left-hand-side-expressions" title="Left-Hand-Side Expressions">13.3 Left-Hand-Side Expressions</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-static-semantics" title="Static Semantics">13.3.1 Static Semantics</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-left-hand-side-expressions-static-semantics-early-errors" title="Static Semantics: Early Errors">13.3.1.1 SS: Early Errors</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-property-accessors" title="Property Accessors">13.3.2 Property Accessors</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-property-accessors-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.2.1 RS: Evaluation</a></li></ol></li><li><a href="ecmascript-language-expressions.html#sec-evaluate-property-access-with-expression-key" title="EvaluatePropertyAccessWithExpressionKey ( baseValue, expression, strict )">13.3.3 EvaluatePropertyAccessWithExpressionKey ( <var>baseValue</var>, <var>expression</var>, <var>strict</var> )</a></li><li><a href="ecmascript-language-expressions.html#sec-evaluate-property-access-with-identifier-key" title="EvaluatePropertyAccessWithIdentifierKey ( baseValue, identifierName, strict )">13.3.4 EvaluatePropertyAccessWithIdentifierKey ( <var>baseValue</var>, <var>identifierName</var>, <var>strict</var> )</a></li><li>+<a href="ecmascript-language-expressions.html#sec-new-operator" title="The new Operator">13.3.5 The <code>new</code> Operator</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-new-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.5.1 RS: Evaluation</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-evaluatenew" title="EvaluateNew ( constructExpr, arguments )">13.3.5.1.1 EvaluateNew ( <var>constructExpr</var>, <var>arguments</var> )</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-function-calls" title="Function Calls">13.3.6 Function Calls</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-function-calls-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.6.1 RS: Evaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-evaluatecall" title="EvaluateCall ( func, ref, arguments, tailPosition )">13.3.6.2 EvaluateCall ( <var>func</var>, <var>ref</var>, <var>arguments</var>, <var>tailPosition</var> )</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-super-keyword" title="The super Keyword">13.3.7 The <code>super</code> Keyword</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-super-keyword-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.7.1 RS: Evaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-getsuperconstructor" title="GetSuperConstructor ( )">13.3.7.2 GetSuperConstructor ( )</a></li><li><a href="ecmascript-language-expressions.html#sec-makesuperpropertyreference" title="MakeSuperPropertyReference ( actualThis, propertyKey, strict )">13.3.7.3 MakeSuperPropertyReference ( <var>actualThis</var>, <var>propertyKey</var>, <var>strict</var> )</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-argument-lists" title="Argument Lists">13.3.8 Argument Lists</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-argumentlistevaluation" title="Runtime Semantics: ArgumentListEvaluation">13.3.8.1 RS: ArgumentListEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-optional-chains" title="Optional Chains">13.3.9 Optional Chains</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-optional-chaining-evaluation" title="Runtime Semantics: Evaluation">13.3.9.1 RS: Evaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-optional-chaining-chain-evaluation" title="Runtime Semantics: ChainEvaluation">13.3.9.2 RS: ChainEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-import-calls" title="Import Calls">13.3.10 Import Calls</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-import-call-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.10.1 RS: Evaluation</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-ContinueDynamicImport" title="ContinueDynamicImport ( promiseCapability, moduleCompletion )">13.3.10.1.1 ContinueDynamicImport ( <var>promiseCapability</var>, <var>moduleCompletion</var> )</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-tagged-templates" title="Tagged Templates">13.3.11 Tagged Templates</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-tagged-templates-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.11.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-meta-properties" title="Meta Properties">13.3.12 Meta Properties</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-meta-properties-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.3.12.1 RS: Evaluation</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-hostgetimportmetaproperties" title="HostGetImportMetaProperties ( moduleRecord )">13.3.12.1.1 HostGetImportMetaProperties ( <var>moduleRecord</var> )</a></li><li><a href="ecmascript-language-expressions.html#sec-hostfinalizeimportmeta" title="HostFinalizeImportMeta ( importMeta, moduleRecord )">13.3.12.1.2 HostFinalizeImportMeta ( <var>importMeta</var>, <var>moduleRecord</var> )</a></li></ol></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-update-expressions" title="Update Expressions">13.4 Update Expressions</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-update-expressions-static-semantics-early-errors" title="Static Semantics: Early Errors">13.4.1 SS: Early Errors</a></li><li>+<a href="ecmascript-language-expressions.html#sec-postfix-increment-operator" title="Postfix Increment Operator">13.4.2 Postfix Increment Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-postfix-increment-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.4.2.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-postfix-decrement-operator" title="Postfix Decrement Operator">13.4.3 Postfix Decrement Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-postfix-decrement-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.4.3.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-prefix-increment-operator" title="Prefix Increment Operator">13.4.4 Prefix Increment Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-prefix-increment-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.4.4.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-prefix-decrement-operator" title="Prefix Decrement Operator">13.4.5 Prefix Decrement Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-prefix-decrement-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.4.5.1 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-unary-operators" title="Unary Operators">13.5 Unary Operators</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-delete-operator" title="The delete Operator">13.5.1 The <code>delete</code> Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-delete-operator-static-semantics-early-errors" title="Static Semantics: Early Errors">13.5.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-delete-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.1.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-void-operator" title="The void Operator">13.5.2 The <code>void</code> Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-void-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.2.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-typeof-operator" title="The typeof Operator">13.5.3 The <code>typeof</code> Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-typeof-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.3.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-unary-plus-operator" title="Unary + Operator">13.5.4 Unary <code>+</code> Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-unary-plus-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.4.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-unary-minus-operator" title="Unary - Operator">13.5.5 Unary <code>-</code> Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-unary-minus-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.5.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-bitwise-not-operator" title="Bitwise NOT Operator ( ~ )">13.5.6 Bitwise NOT Operator ( <code>~</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-bitwise-not-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.6.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-logical-not-operator" title="Logical NOT Operator ( ! )">13.5.7 Logical NOT Operator ( <code>!</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-logical-not-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.5.7.1 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-exp-operator" title="Exponentiation Operator">13.6 Exponentiation Operator</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-exp-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.6.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-multiplicative-operators" title="Multiplicative Operators">13.7 Multiplicative Operators</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-multiplicative-operators-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.7.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-additive-operators" title="Additive Operators">13.8 Additive Operators</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-addition-operator-plus" title="The Addition Operator ( + )">13.8.1 The Addition Operator ( <code>+</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-addition-operator-plus-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.8.1.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-subtraction-operator-minus" title="The Subtraction Operator ( - )">13.8.2 The Subtraction Operator ( <code>-</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-subtraction-operator-minus-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.8.2.1 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-bitwise-shift-operators" title="Bitwise Shift Operators">13.9 Bitwise Shift Operators</a><ol class="toc"><li>+<a href="ecmascript-language-expressions.html#sec-left-shift-operator" title="The Left Shift Operator ( << )">13.9.1 The Left Shift Operator ( <code><<</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-left-shift-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.9.1.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-signed-right-shift-operator" title="The Signed Right Shift Operator ( >> )">13.9.2 The Signed Right Shift Operator ( <code>>></code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-signed-right-shift-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.9.2.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-unsigned-right-shift-operator" title="The Unsigned Right Shift Operator ( >>> )">13.9.3 The Unsigned Right Shift Operator ( <code>>>></code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-unsigned-right-shift-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.9.3.1 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-relational-operators" title="Relational Operators">13.10 Relational Operators</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-relational-operators-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.10.1 RS: Evaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-instanceofoperator" title="InstanceofOperator ( V, target )">13.10.2 InstanceofOperator ( <var>V</var>, <var>target</var> )</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-equality-operators" title="Equality Operators">13.11 Equality Operators</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-equality-operators-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.11.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-binary-bitwise-operators" title="Binary Bitwise Operators">13.12 Binary Bitwise Operators</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-binary-bitwise-operators-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.12.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-binary-logical-operators" title="Binary Logical Operators">13.13 Binary Logical Operators</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-binary-logical-operators-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.13.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-conditional-operator" title="Conditional Operator ( ? : )">13.14 Conditional Operator ( <code>? :</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-conditional-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.14.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-assignment-operators" title="Assignment Operators">13.15 Assignment Operators</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-assignment-operators-static-semantics-early-errors" title="Static Semantics: Early Errors">13.15.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-assignment-operators-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.15.2 RS: Evaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-applystringornumericbinaryoperator" title="ApplyStringOrNumericBinaryOperator ( lVal, opText, rVal )">13.15.3 ApplyStringOrNumericBinaryOperator ( <var>lVal</var>, <var>opText</var>, <var>rVal</var> )</a></li><li><a href="ecmascript-language-expressions.html#sec-evaluatestringornumericbinaryexpression" title="EvaluateStringOrNumericBinaryExpression ( leftOperand, opText, rightOperand )">13.15.4 EvaluateStringOrNumericBinaryExpression ( <var>leftOperand</var>, <var>opText</var>, <var>rightOperand</var> )</a></li><li>+<a href="ecmascript-language-expressions.html#sec-destructuring-assignment" title="Destructuring Assignment">13.15.5 Destructuring Assignment</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-destructuring-assignment-static-semantics-early-errors" title="Static Semantics: Early Errors">13.15.5.1 SS: Early Errors</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-destructuringassignmentevaluation" title="Runtime Semantics: DestructuringAssignmentEvaluation">13.15.5.2 RS: DestructuringAssignmentEvaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-propertydestructuringassignmentevaluation" title="Runtime Semantics: PropertyDestructuringAssignmentEvaluation">13.15.5.3 RS: PropertyDestructuringAssignmentEvaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-restdestructuringassignmentevaluation" title="Runtime Semantics: RestDestructuringAssignmentEvaluation">13.15.5.4 RS: RestDestructuringAssignmentEvaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-iteratordestructuringassignmentevaluation" title="Runtime Semantics: IteratorDestructuringAssignmentEvaluation">13.15.5.5 RS: IteratorDestructuringAssignmentEvaluation</a></li><li><a href="ecmascript-language-expressions.html#sec-runtime-semantics-keyeddestructuringassignmentevaluation" title="Runtime Semantics: KeyedDestructuringAssignmentEvaluation">13.15.5.6 RS: KeyedDestructuringAssignmentEvaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-expressions.html#sec-comma-operator" title="Comma Operator ( , )">13.16 Comma Operator ( <code>,</code> )</a><ol class="toc"><li><a href="ecmascript-language-expressions.html#sec-comma-operator-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">13.16.1 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-ecmascript-language-statements-and-declarations" title="ECMAScript Language: Statements and Declarations">14 ECMAScript Language: Statements and Declarations</a><ol class="toc"><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-statement-semantics" title="Statement Semantics">14.1 Statement Semantics</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-statement-semantics-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.1.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-block" title="Block">14.2 Block</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-block-static-semantics-early-errors" title="Static Semantics: Early Errors">14.2.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-block-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.2.2 RS: Evaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-blockdeclarationinstantiation" title="BlockDeclarationInstantiation ( code, env )">14.2.3 BlockDeclarationInstantiation ( <var>code</var>, <var>env</var> )</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-declarations-and-the-variable-statement" title="Declarations and the Variable Statement">14.3 Declarations and the Variable Statement</a><ol class="toc"><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-let-and-const-declarations" title="Let and Const Declarations">14.3.1 Let and Const Declarations</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-let-and-const-declarations-static-semantics-early-errors" title="Static Semantics: Early Errors">14.3.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-let-and-const-declarations-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.3.1.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-variable-statement" title="Variable Statement">14.3.2 Variable Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-variable-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.3.2.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-destructuring-binding-patterns" title="Destructuring Binding Patterns">14.3.3 Destructuring Binding Patterns</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-destructuring-binding-patterns-runtime-semantics-propertybindinginitialization" title="Runtime Semantics: PropertyBindingInitialization">14.3.3.1 RS: PropertyBindingInitialization</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-destructuring-binding-patterns-runtime-semantics-restbindinginitialization" title="Runtime Semantics: RestBindingInitialization">14.3.3.2 RS: RestBindingInitialization</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-keyedbindinginitialization" title="Runtime Semantics: KeyedBindingInitialization">14.3.3.3 RS: KeyedBindingInitialization</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-empty-statement" title="Empty Statement">14.4 Empty Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-empty-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.4.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-expression-statement" title="Expression Statement">14.5 Expression Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-expression-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.5.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-if-statement" title="The if Statement">14.6 The <code>if</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-if-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.6.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-if-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.6.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-iteration-statements" title="Iteration Statements">14.7 Iteration Statements</a><ol class="toc"><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-iteration-statements-semantics" title="Semantics">14.7.1 Semantics</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-loopcontinues" title="LoopContinues ( completion, labelSet )">14.7.1.1 LoopContinues ( <var>completion</var>, <var>labelSet</var> )</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-loopevaluation" title="Runtime Semantics: LoopEvaluation">14.7.1.2 RS: LoopEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-do-while-statement" title="The do-while Statement">14.7.2 The <code>do</code>-<code>while</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-do-while-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.7.2.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-dowhileloopevaluation" title="Runtime Semantics: DoWhileLoopEvaluation">14.7.2.2 RS: DoWhileLoopEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-while-statement" title="The while Statement">14.7.3 The <code>while</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-while-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.7.3.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-whileloopevaluation" title="Runtime Semantics: WhileLoopEvaluation">14.7.3.2 RS: WhileLoopEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-for-statement" title="The for Statement">14.7.4 The <code>for</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-for-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.7.4.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forloopevaluation" title="Runtime Semantics: ForLoopEvaluation">14.7.4.2 RS: ForLoopEvaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-forbodyevaluation" title="ForBodyEvaluation ( test, increment, stmt, perIterationBindings, labelSet )">14.7.4.3 ForBodyEvaluation ( <var>test</var>, <var>increment</var>, <var>stmt</var>, <var>perIterationBindings</var>, <var>labelSet</var> )</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-createperiterationenvironment" title="CreatePerIterationEnvironment ( perIterationBindings )">14.7.4.4 CreatePerIterationEnvironment ( <var>perIterationBindings</var> )</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-for-in-and-for-of-statements" title="The for-in, for-of, and for-await-of Statements">14.7.5 The <code>for</code>-<code>in</code>, <code>for</code>-<code>of</code>, and <code>for</code>-<code>await</code>-<code>of</code> Statements</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-and-for-of-statements-static-semantics-early-errors" title="Static Semantics: Early Errors">14.7.5.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-static-semantics-isdestructuring" title="Static Semantics: IsDestructuring">14.7.5.2 SS: IsDestructuring</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-fordeclarationbindinginitialization" title="Runtime Semantics: ForDeclarationBindingInitialization">14.7.5.3 RS: ForDeclarationBindingInitialization</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-fordeclarationbindinginstantiation" title="Runtime Semantics: ForDeclarationBindingInstantiation">14.7.5.4 RS: ForDeclarationBindingInstantiation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofloopevaluation" title="Runtime Semantics: ForInOfLoopEvaluation">14.7.5.5 RS: ForInOfLoopEvaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" title="ForIn/OfHeadEvaluation ( uninitializedBoundNames, expr, iterationKind )">14.7.5.6 ForIn/OfHeadEvaluation ( <var>uninitializedBoundNames</var>, <var>expr</var>, <var>iterationKind</var> )</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" title="ForIn/OfBodyEvaluation ( lhs, stmt, iteratorRecord, iterationKind, lhsKind, labelSet [ , iteratorKind ] )">14.7.5.7 ForIn/OfBodyEvaluation ( <var>lhs</var>, <var>stmt</var>, <var>iteratorRecord</var>, <var>iterationKind</var>, <var>lhsKind</var>, <var>labelSet</var> [ , <var>iteratorKind</var> ] )</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-and-for-of-statements-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.7.5.8 RS: Evaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-enumerate-object-properties" title="EnumerateObjectProperties ( O )">14.7.5.9 EnumerateObjectProperties ( <var>O</var> )</a></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects" title="For-In Iterator Objects">14.7.5.10 For-In Iterator Objects</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-createforiniterator" title="CreateForInIterator ( object )">14.7.5.10.1 CreateForInIterator ( <var>object</var> )</a></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-%foriniteratorprototype%-object" title="The %ForInIteratorPrototype% Object">14.7.5.10.2 The %ForInIteratorPrototype% Object</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-%foriniteratorprototype%.next" title="%ForInIteratorPrototype%.next ( )">14.7.5.10.2.1 %ForInIteratorPrototype%.next ( )</a></li></ol></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-properties-of-for-in-iterator-instances" title="Properties of For-In Iterator Instances">14.7.5.10.3 Properties of For-In Iterator Instances</a></li></ol></li></ol></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-continue-statement" title="The continue Statement">14.8 The <code>continue</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-continue-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.8.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-continue-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.8.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-break-statement" title="The break Statement">14.9 The <code>break</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-break-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.9.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-break-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.9.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-return-statement" title="The return Statement">14.10 The <code>return</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-return-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.10.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-with-statement" title="The with Statement">14.11 The <code>with</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-with-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.11.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-with-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.11.2 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-switch-statement" title="The switch Statement">14.12 The <code>switch</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-switch-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.12.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-caseblockevaluation" title="Runtime Semantics: CaseBlockEvaluation">14.12.2 RS: CaseBlockEvaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-caseclauseisselected" title="CaseClauseIsSelected ( C, input )">14.12.3 CaseClauseIsSelected ( <var>C</var>, <var>input</var> )</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-switch-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.12.4 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-labelled-statements" title="Labelled Statements">14.13 Labelled Statements</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-labelled-statements-static-semantics-early-errors" title="Static Semantics: Early Errors">14.13.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction" title="Static Semantics: IsLabelledFunction ( stmt )">14.13.2 SS: IsLabelledFunction ( <var>stmt</var> )</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-labelled-statements-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.13.3 RS: Evaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-labelledevaluation" title="Runtime Semantics: LabelledEvaluation">14.13.4 RS: LabelledEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-throw-statement" title="The throw Statement">14.14 The <code>throw</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-throw-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.14.1 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-try-statement" title="The try Statement">14.15 The <code>try</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-try-statement-static-semantics-early-errors" title="Static Semantics: Early Errors">14.15.1 SS: Early Errors</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-catchclauseevaluation" title="Runtime Semantics: CatchClauseEvaluation">14.15.2 RS: CatchClauseEvaluation</a></li><li><a href="ecmascript-language-statements-and-declarations.html#sec-try-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.15.3 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-statements-and-declarations.html#sec-debugger-statement" title="The debugger Statement">14.16 The <code>debugger</code> Statement</a><ol class="toc"><li><a href="ecmascript-language-statements-and-declarations.html#sec-debugger-statement-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">14.16.1 RS: Evaluation</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-ecmascript-language-functions-and-classes" title="ECMAScript Language: Functions and Classes">15 ECMAScript Language: Functions and Classes</a><ol class="toc"><li>+<a href="ecmascript-language-functions-and-classes.html#sec-parameter-lists" title="Parameter Lists">15.1 Parameter Lists</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-parameter-lists-static-semantics-early-errors" title="Static Semantics: Early Errors">15.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-containsexpression" title="Static Semantics: ContainsExpression">15.1.2 SS: ContainsExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-issimpleparameterlist" title="Static Semantics: IsSimpleParameterList">15.1.3 SS: IsSimpleParameterList</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-hasinitializer" title="Static Semantics: HasInitializer">15.1.4 SS: HasInitializer</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-expectedargumentcount" title="Static Semantics: ExpectedArgumentCount">15.1.5 SS: ExpectedArgumentCount</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-function-definitions" title="Function Definitions">15.2 Function Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-function-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.2.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-functionbodycontainsusestrict" title="Static Semantics: FunctionBodyContainsUseStrict">15.2.2 SS: FunctionBodyContainsUseStrict</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluatefunctionbody" title="Runtime Semantics: EvaluateFunctionBody">15.2.3 RS: EvaluateFunctionBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateordinaryfunctionobject" title="Runtime Semantics: InstantiateOrdinaryFunctionObject">15.2.4 RS: InstantiateOrdinaryFunctionObject</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateordinaryfunctionexpression" title="Runtime Semantics: InstantiateOrdinaryFunctionExpression">15.2.5 RS: InstantiateOrdinaryFunctionExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-function-definitions-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">15.2.6 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-arrow-function-definitions" title="Arrow Function Definitions">15.3 Arrow Function Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-arrow-function-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.3.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-concisebodycontainsusestrict" title="Static Semantics: ConciseBodyContainsUseStrict">15.3.2 SS: ConciseBodyContainsUseStrict</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluateconcisebody" title="Runtime Semantics: EvaluateConciseBody">15.3.3 RS: EvaluateConciseBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiatearrowfunctionexpression" title="Runtime Semantics: InstantiateArrowFunctionExpression">15.3.4 RS: InstantiateArrowFunctionExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-arrow-function-definitions-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">15.3.5 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-method-definitions" title="Method Definitions">15.4 Method Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-method-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.4.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-hasdirectsuper" title="Static Semantics: HasDirectSuper">15.4.2 SS: HasDirectSuper</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-specialmethod" title="Static Semantics: SpecialMethod">15.4.3 SS: SpecialMethod</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-definemethod" title="Runtime Semantics: DefineMethod">15.4.4 RS: DefineMethod</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-methoddefinitionevaluation" title="Runtime Semantics: MethodDefinitionEvaluation">15.4.5 RS: MethodDefinitionEvaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-generator-function-definitions" title="Generator Function Definitions">15.5 Generator Function Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-generator-function-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.5.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluategeneratorbody" title="Runtime Semantics: EvaluateGeneratorBody">15.5.2 RS: EvaluateGeneratorBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiategeneratorfunctionobject" title="Runtime Semantics: InstantiateGeneratorFunctionObject">15.5.3 RS: InstantiateGeneratorFunctionObject</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiategeneratorfunctionexpression" title="Runtime Semantics: InstantiateGeneratorFunctionExpression">15.5.4 RS: InstantiateGeneratorFunctionExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-generator-function-definitions-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">15.5.5 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-async-generator-function-definitions" title="Async Generator Function Definitions">15.6 Async Generator Function Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-async-generator-function-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.6.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluateasyncgeneratorbody" title="Runtime Semantics: EvaluateAsyncGeneratorBody">15.6.2 RS: EvaluateAsyncGeneratorBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateasyncgeneratorfunctionobject" title="Runtime Semantics: InstantiateAsyncGeneratorFunctionObject">15.6.3 RS: InstantiateAsyncGeneratorFunctionObject</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateasyncgeneratorfunctionexpression" title="Runtime Semantics: InstantiateAsyncGeneratorFunctionExpression">15.6.4 RS: InstantiateAsyncGeneratorFunctionExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-asyncgenerator-definitions-evaluation" title="Runtime Semantics: Evaluation">15.6.5 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-class-definitions" title="Class Definitions">15.7 Class Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-class-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.7.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-classelementkind" title="Static Semantics: ClassElementKind">15.7.2 SS: ClassElementKind</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-constructormethod" title="Static Semantics: ConstructorMethod">15.7.3 SS: ConstructorMethod</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-isstatic" title="Static Semantics: IsStatic">15.7.4 SS: IsStatic</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-nonconstructorelements" title="Static Semantics: NonConstructorElements">15.7.5 SS: NonConstructorElements</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-prototypepropertynamelist" title="Static Semantics: PrototypePropertyNameList">15.7.6 SS: PrototypePropertyNameList</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-allprivateidentifiersvalid" title="Static Semantics: AllPrivateIdentifiersValid">15.7.7 SS: AllPrivateIdentifiersValid</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-privateboundidentifiers" title="Static Semantics: PrivateBoundIdentifiers">15.7.8 SS: PrivateBoundIdentifiers</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-containsarguments" title="Static Semantics: ContainsArguments">15.7.9 SS: ContainsArguments</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-classfielddefinitionevaluation" title="Runtime Semantics: ClassFieldDefinitionEvaluation">15.7.10 RS: ClassFieldDefinitionEvaluation</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-classstaticblockdefinitionevaluation" title="Runtime Semantics: ClassStaticBlockDefinitionEvaluation">15.7.11 RS: ClassStaticBlockDefinitionEvaluation</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluateclassstaticblockbody" title="Runtime Semantics: EvaluateClassStaticBlockBody">15.7.12 RS: EvaluateClassStaticBlockBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-classelementevaluation" title="Runtime Semantics: ClassElementEvaluation">15.7.13 RS: ClassElementEvaluation</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-classdefinitionevaluation" title="Runtime Semantics: ClassDefinitionEvaluation">15.7.14 RS: ClassDefinitionEvaluation</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-bindingclassdeclarationevaluation" title="Runtime Semantics: BindingClassDeclarationEvaluation">15.7.15 RS: BindingClassDeclarationEvaluation</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-class-definitions-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">15.7.16 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-async-function-definitions" title="Async Function Definitions">15.8 Async Function Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-async-function-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.8.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateasyncfunctionobject" title="Runtime Semantics: InstantiateAsyncFunctionObject">15.8.2 RS: InstantiateAsyncFunctionObject</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateasyncfunctionexpression" title="Runtime Semantics: InstantiateAsyncFunctionExpression">15.8.3 RS: InstantiateAsyncFunctionExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluateasyncfunctionbody" title="Runtime Semantics: EvaluateAsyncFunctionBody">15.8.4 RS: EvaluateAsyncFunctionBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-async-function-definitions-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">15.8.5 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-async-arrow-function-definitions" title="Async Arrow Function Definitions">15.9 Async Arrow Function Definitions</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-async-arrow-function-definitions-static-semantics-early-errors" title="Static Semantics: Early Errors">15.9.1 SS: Early Errors</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-asyncconcisebodycontainsusestrict" title="Static Semantics: AsyncConciseBodyContainsUseStrict">15.9.2 SS: AsyncConciseBodyContainsUseStrict</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-evaluateasyncconcisebody" title="Runtime Semantics: EvaluateAsyncConciseBody">15.9.3 RS: EvaluateAsyncConciseBody</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-runtime-semantics-instantiateasyncarrowfunctionexpression" title="Runtime Semantics: InstantiateAsyncArrowFunctionExpression">15.9.4 RS: InstantiateAsyncArrowFunctionExpression</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-async-arrow-function-definitions-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">15.9.5 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-functions-and-classes.html#sec-tail-position-calls" title="Tail Position Calls">15.10 Tail Position Calls</a><ol class="toc"><li><a href="ecmascript-language-functions-and-classes.html#sec-isintailposition" title="Static Semantics: IsInTailPosition ( call )">15.10.1 SS: IsInTailPosition ( <var>call</var> )</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-static-semantics-hascallintailposition" title="Static Semantics: HasCallInTailPosition">15.10.2 SS: HasCallInTailPosition</a></li><li><a href="ecmascript-language-functions-and-classes.html#sec-preparefortailcall" title="PrepareForTailCall ( )">15.10.3 PrepareForTailCall ( )</a></li></ol></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-ecmascript-language-scripts-and-modules" title="ECMAScript Language: Scripts and Modules">16 ECMAScript Language: Scripts and Modules</a><ol class="toc"><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-scripts" title="Scripts">16.1 Scripts</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-scripts-static-semantics-early-errors" title="Static Semantics: Early Errors">16.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-scriptisstrict" title="Static Semantics: ScriptIsStrict">16.1.2 SS: ScriptIsStrict</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-script-semantics-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">16.1.3 RS: Evaluation</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-script-records" title="Script Records">16.1.4 Script Records</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-parse-script" title="ParseScript ( sourceText, realm, hostDefined )">16.1.5 ParseScript ( <var>sourceText</var>, <var>realm</var>, <var>hostDefined</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-runtime-semantics-scriptevaluation" title="ScriptEvaluation ( scriptRecord )">16.1.6 ScriptEvaluation ( <var>scriptRecord</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-globaldeclarationinstantiation" title="GlobalDeclarationInstantiation ( script, env )">16.1.7 GlobalDeclarationInstantiation ( <var>script</var>, <var>env</var> )</a></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-modules" title="Modules">16.2 Modules</a><ol class="toc"><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-module-semantics" title="Module Semantics">16.2.1 Module Semantics</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-module-semantics-static-semantics-early-errors" title="Static Semantics: Early Errors">16.2.1.1 SS: Early Errors</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-importedlocalnames" title="Static Semantics: ImportedLocalNames ( importEntries )">16.2.1.2 SS: ImportedLocalNames ( <var>importEntries</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-modulerequests" title="Static Semantics: ModuleRequests">16.2.1.3 SS: ModuleRequests</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-abstract-module-records" title="Abstract Module Records">16.2.1.4 Abstract Module Records</a></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-cyclic-module-records" title="Cyclic Module Records">16.2.1.5 Cyclic Module Records</a><ol class="toc"><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-LoadRequestedModules" title="LoadRequestedModules ( [ hostDefined ] )">16.2.1.5.1 LoadRequestedModules ( [ <var>hostDefined</var> ] )</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-InnerModuleLoading" title="InnerModuleLoading ( state, module )">16.2.1.5.1.1 InnerModuleLoading ( <var>state</var>, <var>module</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-ContinueModuleLoading" title="ContinueModuleLoading ( state, moduleCompletion )">16.2.1.5.1.2 ContinueModuleLoading ( <var>state</var>, <var>moduleCompletion</var> )</a></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-moduledeclarationlinking" title="Link ( )">16.2.1.5.2 Link ( )</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-InnerModuleLinking" title="InnerModuleLinking ( module, stack, index )">16.2.1.5.2.1 InnerModuleLinking ( <var>module</var>, <var>stack</var>, <var>index</var> )</a></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-moduleevaluation" title="Evaluate ( )">16.2.1.5.3 Evaluate ( )</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-innermoduleevaluation" title="InnerModuleEvaluation ( module, stack, index )">16.2.1.5.3.1 InnerModuleEvaluation ( <var>module</var>, <var>stack</var>, <var>index</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-execute-async-module" title="ExecuteAsyncModule ( module )">16.2.1.5.3.2 ExecuteAsyncModule ( <var>module</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-gather-available-ancestors" title="GatherAvailableAncestors ( module, execList )">16.2.1.5.3.3 GatherAvailableAncestors ( <var>module</var>, <var>execList</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-async-module-execution-fulfilled" title="AsyncModuleExecutionFulfilled ( module )">16.2.1.5.3.4 AsyncModuleExecutionFulfilled ( <var>module</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-async-module-execution-rejected" title="AsyncModuleExecutionRejected ( module, error )">16.2.1.5.3.5 AsyncModuleExecutionRejected ( <var>module</var>, <var>error</var> )</a></li></ol></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-example-cyclic-module-record-graphs" title="Example Cyclic Module Record Graphs">16.2.1.5.4 Example Cyclic Module Record Graphs</a></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-source-text-module-records" title="Source Text Module Records">16.2.1.6 Source Text Module Records</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-parsemodule" title="ParseModule ( sourceText, realm, hostDefined )">16.2.1.6.1 ParseModule ( <var>sourceText</var>, <var>realm</var>, <var>hostDefined</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-getexportednames" title="GetExportedNames ( [ exportStarSet ] )">16.2.1.6.2 GetExportedNames ( [ <var>exportStarSet</var> ] )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-resolveexport" title="ResolveExport ( exportName [ , resolveSet ] )">16.2.1.6.3 ResolveExport ( <var>exportName</var> [ , <var>resolveSet</var> ] )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-source-text-module-record-initialize-environment" title="InitializeEnvironment ( )">16.2.1.6.4 InitializeEnvironment ( )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-source-text-module-record-execute-module" title="ExecuteModule ( [ capability ] )">16.2.1.6.5 ExecuteModule ( [ <var>capability</var> ] )</a></li></ol></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-GetImportedModule" title="GetImportedModule ( referrer, specifier )">16.2.1.7 GetImportedModule ( <var>referrer</var>, <var>specifier</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-HostLoadImportedModule" title="HostLoadImportedModule ( referrer, specifier, hostDefined, payload )">16.2.1.8 HostLoadImportedModule ( <var>referrer</var>, <var>specifier</var>, <var>hostDefined</var>, <var>payload</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-FinishLoadingImportedModule" title="FinishLoadingImportedModule ( referrer, specifier, payload, result )">16.2.1.9 FinishLoadingImportedModule ( <var>referrer</var>, <var>specifier</var>, <var>payload</var>, <var>result</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-getmodulenamespace" title="GetModuleNamespace ( module )">16.2.1.10 GetModuleNamespace ( <var>module</var> )</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-module-semantics-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">16.2.1.11 RS: Evaluation</a></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-imports" title="Imports">16.2.2 Imports</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-imports-static-semantics-early-errors" title="Static Semantics: Early Errors">16.2.2.1 SS: Early Errors</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-importentries" title="Static Semantics: ImportEntries">16.2.2.2 SS: ImportEntries</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-importentriesformodule" title="Static Semantics: ImportEntriesForModule">16.2.2.3 SS: ImportEntriesForModule</a></li></ol></li><li>+<a href="ecmascript-language-scripts-and-modules.html#sec-exports" title="Exports">16.2.3 Exports</a><ol class="toc"><li><a href="ecmascript-language-scripts-and-modules.html#sec-exports-static-semantics-early-errors" title="Static Semantics: Early Errors">16.2.3.1 SS: Early Errors</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-exportedbindings" title="Static Semantics: ExportedBindings">16.2.3.2 SS: ExportedBindings</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-exportednames" title="Static Semantics: ExportedNames">16.2.3.3 SS: ExportedNames</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-exportentries" title="Static Semantics: ExportEntries">16.2.3.4 SS: ExportEntries</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-exportentriesformodule" title="Static Semantics: ExportEntriesForModule">16.2.3.5 SS: ExportEntriesForModule</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-static-semantics-referencedbindings" title="Static Semantics: ReferencedBindings">16.2.3.6 SS: ReferencedBindings</a></li><li><a href="ecmascript-language-scripts-and-modules.html#sec-exports-runtime-semantics-evaluation" title="Runtime Semantics: Evaluation">16.2.3.7 RS: Evaluation</a></li></ol></li></ol></li></ol></li><li>+<a href="error-handling-and-language-extensions.html#sec-error-handling-and-language-extensions" title="Error Handling and Language Extensions">17 Error Handling and Language Extensions</a><ol class="toc"><li><a href="error-handling-and-language-extensions.html#sec-forbidden-extensions" title="Forbidden Extensions">17.1 Forbidden Extensions</a></li></ol></li><li><a href="ecmascript-standard-built-in-objects.html#sec-ecmascript-standard-built-in-objects" title="ECMAScript Standard Built-in Objects">18 ECMAScript Standard Built-in Objects</a></li><li>+<a href="global-object.html#sec-global-object" title="The Global Object">19 The Global Object</a><ol class="toc"><li>+<a href="global-object.html#sec-value-properties-of-the-global-object" title="Value Properties of the Global Object">19.1 Value Properties of the Global Object</a><ol class="toc"><li><a href="global-object.html#sec-globalthis" title="globalThis">19.1.1 globalThis</a></li><li><a href="global-object.html#sec-value-properties-of-the-global-object-infinity" title="Infinity">19.1.2 Infinity</a></li><li><a href="global-object.html#sec-value-properties-of-the-global-object-nan" title="NaN">19.1.3 NaN</a></li><li><a href="global-object.html#sec-undefined" title="undefined">19.1.4 undefined</a></li></ol></li><li>+<a href="global-object.html#sec-function-properties-of-the-global-object" title="Function Properties of the Global Object">19.2 Function Properties of the Global Object</a><ol class="toc"><li>+<a href="global-object.html#sec-eval-x" title="eval ( x )">19.2.1 eval ( <var>x</var> )</a><ol class="toc"><li><a href="global-object.html#sec-performeval" title="PerformEval ( x, strictCaller, direct )">19.2.1.1 PerformEval ( <var>x</var>, <var>strictCaller</var>, <var>direct</var> )</a></li><li><a href="global-object.html#sec-hostensurecancompilestrings" title="HostEnsureCanCompileStrings ( calleeRealm, parameterStrings, bodyString, direct )">19.2.1.2 HostEnsureCanCompileStrings ( <var>calleeRealm</var>, <var>parameterStrings</var>, <var>bodyString</var>, <var>direct</var> )</a></li><li><a href="global-object.html#sec-evaldeclarationinstantiation" title="EvalDeclarationInstantiation ( body, varEnv, lexEnv, privateEnv, strict )">19.2.1.3 EvalDeclarationInstantiation ( <var>body</var>, <var>varEnv</var>, <var>lexEnv</var>, <var>privateEnv</var>, <var>strict</var> )</a></li></ol></li><li><a href="global-object.html#sec-isfinite-number" title="isFinite ( number )">19.2.2 isFinite ( <var>number</var> )</a></li><li><a href="global-object.html#sec-isnan-number" title="isNaN ( number )">19.2.3 isNaN ( <var>number</var> )</a></li><li><a href="global-object.html#sec-parsefloat-string" title="parseFloat ( string )">19.2.4 parseFloat ( <var>string</var> )</a></li><li><a href="global-object.html#sec-parseint-string-radix" title="parseInt ( string, radix )">19.2.5 parseInt ( <var>string</var>, <var>radix</var> )</a></li><li>+<a href="global-object.html#sec-uri-handling-functions" title="URI Handling Functions">19.2.6 URI Handling Functions</a><ol class="toc"><li><a href="global-object.html#sec-decodeuri-encodeduri" title="decodeURI ( encodedURI )">19.2.6.1 decodeURI ( <var>encodedURI</var> )</a></li><li><a href="global-object.html#sec-decodeuricomponent-encodeduricomponent" title="decodeURIComponent ( encodedURIComponent )">19.2.6.2 decodeURIComponent ( <var>encodedURIComponent</var> )</a></li><li><a href="global-object.html#sec-encodeuri-uri" title="encodeURI ( uri )">19.2.6.3 encodeURI ( <var>uri</var> )</a></li><li><a href="global-object.html#sec-encodeuricomponent-uricomponent" title="encodeURIComponent ( uriComponent )">19.2.6.4 encodeURIComponent ( <var>uriComponent</var> )</a></li><li><a href="global-object.html#sec-encode" title="Encode ( string, extraUnescaped )">19.2.6.5 Encode ( <var>string</var>, <var>extraUnescaped</var> )</a></li><li><a href="global-object.html#sec-decode" title="Decode ( string, preserveEscapeSet )">19.2.6.6 Decode ( <var>string</var>, <var>preserveEscapeSet</var> )</a></li><li><a href="global-object.html#sec-parsehexoctet" title="ParseHexOctet ( string, position )">19.2.6.7 ParseHexOctet ( <var>string</var>, <var>position</var> )</a></li></ol></li></ol></li><li>+<a href="global-object.html#sec-constructor-properties-of-the-global-object" title="Constructor Properties of the Global Object">19.3 Constructor Properties of the Global Object</a><ol class="toc"><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-aggregate-error" title="AggregateError ( . . . )">19.3.1 AggregateError ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-array" title="Array ( . . . )">19.3.2 Array ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-arraybuffer" title="ArrayBuffer ( . . . )">19.3.3 ArrayBuffer ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-bigint" title="BigInt ( . . . )">19.3.4 BigInt ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-bigint64array" title="BigInt64Array ( . . . )">19.3.5 BigInt64Array ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-biguint64array" title="BigUint64Array ( . . . )">19.3.6 BigUint64Array ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-boolean" title="Boolean ( . . . )">19.3.7 Boolean ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-dataview" title="DataView ( . . . )">19.3.8 DataView ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-date" title="Date ( . . . )">19.3.9 Date ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-error" title="Error ( . . . )">19.3.10 Error ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-evalerror" title="EvalError ( . . . )">19.3.11 EvalError ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-finalization-registry" title="FinalizationRegistry ( . . . )">19.3.12 FinalizationRegistry ( . . . )</a></li><li><a href="global-object.html#sec-float32array" title="Float32Array ( . . . )">19.3.13 Float32Array ( . . . )</a></li><li><a href="global-object.html#sec-float64array" title="Float64Array ( . . . )">19.3.14 Float64Array ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-function" title="Function ( . . . )">19.3.15 Function ( . . . )</a></li><li><a href="global-object.html#sec-int8array" title="Int8Array ( . . . )">19.3.16 Int8Array ( . . . )</a></li><li><a href="global-object.html#sec-int16array" title="Int16Array ( . . . )">19.3.17 Int16Array ( . . . )</a></li><li><a href="global-object.html#sec-int32array" title="Int32Array ( . . . )">19.3.18 Int32Array ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-iterator" title="Iterator ( . . . )">19.3.19 Iterator ( . . . )</a></li><li><a href="global-object.html#sec-map" title="Map ( . . . )">19.3.20 Map ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-number" title="Number ( . . . )">19.3.21 Number ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-object" title="Object ( . . . )">19.3.22 Object ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-promise" title="Promise ( . . . )">19.3.23 Promise ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-proxy" title="Proxy ( . . . )">19.3.24 Proxy ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-rangeerror" title="RangeError ( . . . )">19.3.25 RangeError ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-referenceerror" title="ReferenceError ( . . . )">19.3.26 ReferenceError ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-regexp" title="RegExp ( . . . )">19.3.27 RegExp ( . . . )</a></li><li><a href="global-object.html#sec-set" title="Set ( . . . )">19.3.28 Set ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-sharedarraybuffer" title="SharedArrayBuffer ( . . . )">19.3.29 SharedArrayBuffer ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-string" title="String ( . . . )">19.3.30 String ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-symbol" title="Symbol ( . . . )">19.3.31 Symbol ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-syntaxerror" title="SyntaxError ( . . . )">19.3.32 SyntaxError ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-typeerror" title="TypeError ( . . . )">19.3.33 TypeError ( . . . )</a></li><li><a href="global-object.html#sec-uint8array" title="Uint8Array ( . . . )">19.3.34 Uint8Array ( . . . )</a></li><li><a href="global-object.html#sec-uint8clampedarray" title="Uint8ClampedArray ( . . . )">19.3.35 Uint8ClampedArray ( . . . )</a></li><li><a href="global-object.html#sec-uint16array" title="Uint16Array ( . . . )">19.3.36 Uint16Array ( . . . )</a></li><li><a href="global-object.html#sec-uint32array" title="Uint32Array ( . . . )">19.3.37 Uint32Array ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-urierror" title="URIError ( . . . )">19.3.38 URIError ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-weakmap" title="WeakMap ( . . . )">19.3.39 WeakMap ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-weakref" title="WeakRef ( . . . )">19.3.40 WeakRef ( . . . )</a></li><li><a href="global-object.html#sec-constructor-properties-of-the-global-object-weakset" title="WeakSet ( . . . )">19.3.41 WeakSet ( . . . )</a></li></ol></li><li>+<a href="global-object.html#sec-other-properties-of-the-global-object" title="Other Properties of the Global Object">19.4 Other Properties of the Global Object</a><ol class="toc"><li><a href="global-object.html#sec-atomics" title="Atomics">19.4.1 Atomics</a></li><li><a href="global-object.html#sec-json" title="JSON">19.4.2 JSON</a></li><li><a href="global-object.html#sec-math" title="Math">19.4.3 Math</a></li><li><a href="global-object.html#sec-reflect" title="Reflect">19.4.4 Reflect</a></li></ol></li></ol></li><li>+<a href="fundamental-objects.html#sec-fundamental-objects" title="Fundamental Objects">20 Fundamental Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-object-objects" title="Object Objects">20.1 Object Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-object-constructor" title="The Object Constructor">20.1.1 The Object Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-object-value" title="Object ( [ value ] )">20.1.1.1 Object ( [ <var>value</var> ] )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-object-constructor" title="Properties of the Object Constructor">20.1.2 Properties of the Object Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-object.assign" title="Object.assign ( target, ...sources )">20.1.2.1 Object.assign ( <var>target</var>, ...<var>sources</var> )</a></li><li><a href="fundamental-objects.html#sec-object.create" title="Object.create ( O, Properties )">20.1.2.2 Object.create ( <var>O</var>, <var>Properties</var> )</a></li><li>+<a href="fundamental-objects.html#sec-object.defineproperties" title="Object.defineProperties ( O, Properties )">20.1.2.3 Object.defineProperties ( <var>O</var>, <var>Properties</var> )</a><ol class="toc"><li><a href="fundamental-objects.html#sec-objectdefineproperties" title="ObjectDefineProperties ( O, Properties )">20.1.2.3.1 ObjectDefineProperties ( <var>O</var>, <var>Properties</var> )</a></li></ol></li><li><a href="fundamental-objects.html#sec-object.defineproperty" title="Object.defineProperty ( O, P, Attributes )">20.1.2.4 Object.defineProperty ( <var>O</var>, <var>P</var>, <var>Attributes</var> )</a></li><li><a href="fundamental-objects.html#sec-object.entries" title="Object.entries ( O )">20.1.2.5 Object.entries ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.freeze" title="Object.freeze ( O )">20.1.2.6 Object.freeze ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.fromentries" title="Object.fromEntries ( iterable )">20.1.2.7 Object.fromEntries ( <var>iterable</var> )</a></li><li><a href="fundamental-objects.html#sec-object.getownpropertydescriptor" title="Object.getOwnPropertyDescriptor ( O, P )">20.1.2.8 Object.getOwnPropertyDescriptor ( <var>O</var>, <var>P</var> )</a></li><li><a href="fundamental-objects.html#sec-object.getownpropertydescriptors" title="Object.getOwnPropertyDescriptors ( O )">20.1.2.9 Object.getOwnPropertyDescriptors ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.getownpropertynames" title="Object.getOwnPropertyNames ( O )">20.1.2.10 Object.getOwnPropertyNames ( <var>O</var> )</a></li><li>+<a href="fundamental-objects.html#sec-object.getownpropertysymbols" title="Object.getOwnPropertySymbols ( O )">20.1.2.11 Object.getOwnPropertySymbols ( <var>O</var> )</a><ol class="toc"><li><a href="fundamental-objects.html#sec-getownpropertykeys" title="GetOwnPropertyKeys ( O, type )">20.1.2.11.1 GetOwnPropertyKeys ( <var>O</var>, <var>type</var> )</a></li></ol></li><li><a href="fundamental-objects.html#sec-object.getprototypeof" title="Object.getPrototypeOf ( O )">20.1.2.12 Object.getPrototypeOf ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.groupby" title="Object.groupBy ( items, callback )">20.1.2.13 Object.groupBy ( <var>items</var>, <var>callback</var> )</a></li><li><a href="fundamental-objects.html#sec-object.hasown" title="Object.hasOwn ( O, P )">20.1.2.14 Object.hasOwn ( <var>O</var>, <var>P</var> )</a></li><li><a href="fundamental-objects.html#sec-object.is" title="Object.is ( value1, value2 )">20.1.2.15 Object.is ( <var>value1</var>, <var>value2</var> )</a></li><li><a href="fundamental-objects.html#sec-object.isextensible" title="Object.isExtensible ( O )">20.1.2.16 Object.isExtensible ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.isfrozen" title="Object.isFrozen ( O )">20.1.2.17 Object.isFrozen ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.issealed" title="Object.isSealed ( O )">20.1.2.18 Object.isSealed ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.keys" title="Object.keys ( O )">20.1.2.19 Object.keys ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.preventextensions" title="Object.preventExtensions ( O )">20.1.2.20 Object.preventExtensions ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype" title="Object.prototype">20.1.2.21 Object.prototype</a></li><li><a href="fundamental-objects.html#sec-object.seal" title="Object.seal ( O )">20.1.2.22 Object.seal ( <var>O</var> )</a></li><li><a href="fundamental-objects.html#sec-object.setprototypeof" title="Object.setPrototypeOf ( O, proto )">20.1.2.23 Object.setPrototypeOf ( <var>O</var>, <var>proto</var> )</a></li><li><a href="fundamental-objects.html#sec-object.values" title="Object.values ( O )">20.1.2.24 Object.values ( <var>O</var> )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-object-prototype-object" title="Properties of the Object Prototype Object">20.1.3 Properties of the Object Prototype Object</a><ol class="toc"><li><a href="fundamental-objects.html#sec-object.prototype.constructor" title="Object.prototype.constructor">20.1.3.1 Object.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-object.prototype.hasownproperty" title="Object.prototype.hasOwnProperty ( V )">20.1.3.2 Object.prototype.hasOwnProperty ( <var>V</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.isprototypeof" title="Object.prototype.isPrototypeOf ( V )">20.1.3.3 Object.prototype.isPrototypeOf ( <var>V</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.propertyisenumerable" title="Object.prototype.propertyIsEnumerable ( V )">20.1.3.4 Object.prototype.propertyIsEnumerable ( <var>V</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.tolocalestring" title="Object.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] )">20.1.3.5 Object.prototype.toLocaleString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.tostring" title="Object.prototype.toString ( )">20.1.3.6 Object.prototype.toString ( )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.valueof" title="Object.prototype.valueOf ( )">20.1.3.7 Object.prototype.valueOf ( )</a></li><li>+<a href="fundamental-objects.html#sec-object.prototype.__proto__" title="Object.prototype.__proto__">20.1.3.8 Object.prototype.__proto__</a><ol class="toc"><li><a href="fundamental-objects.html#sec-get-object.prototype.__proto__" title="get Object.prototype.__proto__">20.1.3.8.1 get Object.prototype.__proto__</a></li><li><a href="fundamental-objects.html#sec-set-object.prototype.__proto__" title="set Object.prototype.__proto__">20.1.3.8.2 set Object.prototype.__proto__</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-object.prototype-legacy-accessor-methods" title="Legacy Object.prototype Accessor Methods">20.1.3.9 Legacy Object.prototype Accessor Methods</a><ol class="toc"><li><a href="fundamental-objects.html#sec-object.prototype.__defineGetter__" title="Object.prototype.__defineGetter__ ( P, getter )">20.1.3.9.1 Object.prototype.__defineGetter__ ( <var>P</var>, <var>getter</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.__defineSetter__" title="Object.prototype.__defineSetter__ ( P, setter )">20.1.3.9.2 Object.prototype.__defineSetter__ ( <var>P</var>, <var>setter</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.__lookupGetter__" title="Object.prototype.__lookupGetter__ ( P )">20.1.3.9.3 Object.prototype.__lookupGetter__ ( <var>P</var> )</a></li><li><a href="fundamental-objects.html#sec-object.prototype.__lookupSetter__" title="Object.prototype.__lookupSetter__ ( P )">20.1.3.9.4 Object.prototype.__lookupSetter__ ( <var>P</var> )</a></li></ol></li></ol></li><li><a href="fundamental-objects.html#sec-properties-of-object-instances" title="Properties of Object Instances">20.1.4 Properties of Object Instances</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-function-objects" title="Function Objects">20.2 Function Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-function-constructor" title="The Function Constructor">20.2.1 The Function Constructor</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-function-p1-p2-pn-body" title="Function ( ...parameterArgs, bodyArg )">20.2.1.1 Function ( ...<var>parameterArgs</var>, <var>bodyArg</var> )</a><ol class="toc"><li><a href="fundamental-objects.html#sec-createdynamicfunction" title="CreateDynamicFunction ( constructor, newTarget, kind, parameterArgs, bodyArg )">20.2.1.1.1 CreateDynamicFunction ( <var>constructor</var>, <var>newTarget</var>, <var>kind</var>, <var>parameterArgs</var>, <var>bodyArg</var> )</a></li></ol></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-function-constructor" title="Properties of the Function Constructor">20.2.2 Properties of the Function Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-function.prototype" title="Function.prototype">20.2.2.1 Function.prototype</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-function-prototype-object" title="Properties of the Function Prototype Object">20.2.3 Properties of the Function Prototype Object</a><ol class="toc"><li><a href="fundamental-objects.html#sec-function.prototype.apply" title="Function.prototype.apply ( thisArg, argArray )">20.2.3.1 Function.prototype.apply ( <var>thisArg</var>, <var>argArray</var> )</a></li><li><a href="fundamental-objects.html#sec-function.prototype.bind" title="Function.prototype.bind ( thisArg, ...args )">20.2.3.2 Function.prototype.bind ( <var>thisArg</var>, ...<var>args</var> )</a></li><li><a href="fundamental-objects.html#sec-function.prototype.call" title="Function.prototype.call ( thisArg, ...args )">20.2.3.3 Function.prototype.call ( <var>thisArg</var>, ...<var>args</var> )</a></li><li><a href="fundamental-objects.html#sec-function.prototype.constructor" title="Function.prototype.constructor">20.2.3.4 Function.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-function.prototype.tostring" title="Function.prototype.toString ( )">20.2.3.5 Function.prototype.toString ( )</a></li><li><a href="fundamental-objects.html#sec-function.prototype-%symbol.hasinstance%" title="Function.prototype [ %Symbol.hasInstance% ] ( V )">20.2.3.6 Function.prototype [ %Symbol.hasInstance% ] ( <var>V</var> )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-function-instances" title="Function Instances">20.2.4 Function Instances</a><ol class="toc"><li><a href="fundamental-objects.html#sec-function-instances-length" title="length">20.2.4.1 length</a></li><li><a href="fundamental-objects.html#sec-function-instances-name" title="name">20.2.4.2 name</a></li><li><a href="fundamental-objects.html#sec-function-instances-prototype" title="prototype">20.2.4.3 prototype</a></li></ol></li><li><a href="fundamental-objects.html#sec-hosthassourcetextavailable" title="HostHasSourceTextAvailable ( func )">20.2.5 HostHasSourceTextAvailable ( <var>func</var> )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-boolean-objects" title="Boolean Objects">20.3 Boolean Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-boolean-constructor" title="The Boolean Constructor">20.3.1 The Boolean Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-boolean-constructor-boolean-value" title="Boolean ( value )">20.3.1.1 Boolean ( <var>value</var> )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-boolean-constructor" title="Properties of the Boolean Constructor">20.3.2 Properties of the Boolean Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-boolean.prototype" title="Boolean.prototype">20.3.2.1 Boolean.prototype</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-boolean-prototype-object" title="Properties of the Boolean Prototype Object">20.3.3 Properties of the Boolean Prototype Object</a><ol class="toc"><li><a href="fundamental-objects.html#sec-boolean.prototype.constructor" title="Boolean.prototype.constructor">20.3.3.1 Boolean.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-boolean.prototype.tostring" title="Boolean.prototype.toString ( )">20.3.3.2 Boolean.prototype.toString ( )</a></li><li>+<a href="fundamental-objects.html#sec-boolean.prototype.valueof" title="Boolean.prototype.valueOf ( )">20.3.3.3 Boolean.prototype.valueOf ( )</a><ol class="toc"><li><a href="fundamental-objects.html#sec-thisbooleanvalue" title="ThisBooleanValue ( value )">20.3.3.3.1 ThisBooleanValue ( <var>value</var> )</a></li></ol></li></ol></li><li><a href="fundamental-objects.html#sec-properties-of-boolean-instances" title="Properties of Boolean Instances">20.3.4 Properties of Boolean Instances</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-symbol-objects" title="Symbol Objects">20.4 Symbol Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-symbol-constructor" title="The Symbol Constructor">20.4.1 The Symbol Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-symbol-description" title="Symbol ( [ description ] )">20.4.1.1 Symbol ( [ <var>description</var> ] )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-symbol-constructor" title="Properties of the Symbol Constructor">20.4.2 Properties of the Symbol Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-symbol.asynciterator" title="Symbol.asyncIterator">20.4.2.1 Symbol.asyncIterator</a></li><li><a href="fundamental-objects.html#sec-symbol.for" title="Symbol.for ( key )">20.4.2.2 Symbol.for ( <var>key</var> )</a></li><li><a href="fundamental-objects.html#sec-symbol.hasinstance" title="Symbol.hasInstance">20.4.2.3 Symbol.hasInstance</a></li><li><a href="fundamental-objects.html#sec-symbol.isconcatspreadable" title="Symbol.isConcatSpreadable">20.4.2.4 Symbol.isConcatSpreadable</a></li><li><a href="fundamental-objects.html#sec-symbol.iterator" title="Symbol.iterator">20.4.2.5 Symbol.iterator</a></li><li><a href="fundamental-objects.html#sec-symbol.keyfor" title="Symbol.keyFor ( sym )">20.4.2.6 Symbol.keyFor ( <var>sym</var> )</a></li><li><a href="fundamental-objects.html#sec-symbol.match" title="Symbol.match">20.4.2.7 Symbol.match</a></li><li><a href="fundamental-objects.html#sec-symbol.matchall" title="Symbol.matchAll">20.4.2.8 Symbol.matchAll</a></li><li><a href="fundamental-objects.html#sec-symbol.prototype" title="Symbol.prototype">20.4.2.9 Symbol.prototype</a></li><li><a href="fundamental-objects.html#sec-symbol.replace" title="Symbol.replace">20.4.2.10 Symbol.replace</a></li><li><a href="fundamental-objects.html#sec-symbol.search" title="Symbol.search">20.4.2.11 Symbol.search</a></li><li><a href="fundamental-objects.html#sec-symbol.species" title="Symbol.species">20.4.2.12 Symbol.species</a></li><li><a href="fundamental-objects.html#sec-symbol.split" title="Symbol.split">20.4.2.13 Symbol.split</a></li><li><a href="fundamental-objects.html#sec-symbol.toprimitive" title="Symbol.toPrimitive">20.4.2.14 Symbol.toPrimitive</a></li><li><a href="fundamental-objects.html#sec-symbol.tostringtag" title="Symbol.toStringTag">20.4.2.15 Symbol.toStringTag</a></li><li><a href="fundamental-objects.html#sec-symbol.unscopables" title="Symbol.unscopables">20.4.2.16 Symbol.unscopables</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-symbol-prototype-object" title="Properties of the Symbol Prototype Object">20.4.3 Properties of the Symbol Prototype Object</a><ol class="toc"><li><a href="fundamental-objects.html#sec-symbol.prototype.constructor" title="Symbol.prototype.constructor">20.4.3.1 Symbol.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-symbol.prototype.description" title="get Symbol.prototype.description">20.4.3.2 get Symbol.prototype.description</a></li><li>+<a href="fundamental-objects.html#sec-symbol.prototype.tostring" title="Symbol.prototype.toString ( )">20.4.3.3 Symbol.prototype.toString ( )</a><ol class="toc"><li><a href="fundamental-objects.html#sec-symboldescriptivestring" title="SymbolDescriptiveString ( sym )">20.4.3.3.1 SymbolDescriptiveString ( <var>sym</var> )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-symbol.prototype.valueof" title="Symbol.prototype.valueOf ( )">20.4.3.4 Symbol.prototype.valueOf ( )</a><ol class="toc"><li><a href="fundamental-objects.html#sec-thissymbolvalue" title="ThisSymbolValue ( value )">20.4.3.4.1 ThisSymbolValue ( <var>value</var> )</a></li></ol></li><li><a href="fundamental-objects.html#sec-symbol.prototype-%symbol.toprimitive%" title="Symbol.prototype [ %Symbol.toPrimitive% ] ( hint )">20.4.3.5 Symbol.prototype [ %Symbol.toPrimitive% ] ( <var>hint</var> )</a></li><li><a href="fundamental-objects.html#sec-symbol.prototype-%symbol.tostringtag%" title="Symbol.prototype [ %Symbol.toStringTag% ]">20.4.3.6 Symbol.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="fundamental-objects.html#sec-properties-of-symbol-instances" title="Properties of Symbol Instances">20.4.4 Properties of Symbol Instances</a></li><li>+<a href="fundamental-objects.html#sec-abstract-operations-for-symbols" title="Abstract Operations for Symbols">20.4.5 Abstract Operations for Symbols</a><ol class="toc"><li><a href="fundamental-objects.html#sec-keyforsymbol" title="KeyForSymbol ( sym )">20.4.5.1 KeyForSymbol ( <var>sym</var> )</a></li></ol></li></ol></li><li>+<a href="fundamental-objects.html#sec-error-objects" title="Error Objects">20.5 Error Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-error-constructor" title="The Error Constructor">20.5.1 The Error Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-error-message" title="Error ( message [ , options ] )">20.5.1.1 Error ( <var>message</var> [ , <var>options</var> ] )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-error-constructor" title="Properties of the Error Constructor">20.5.2 Properties of the Error Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-error.prototype" title="Error.prototype">20.5.2.1 Error.prototype</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-error-prototype-object" title="Properties of the Error Prototype Object">20.5.3 Properties of the Error Prototype Object</a><ol class="toc"><li><a href="fundamental-objects.html#sec-error.prototype.constructor" title="Error.prototype.constructor">20.5.3.1 Error.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-error.prototype.message" title="Error.prototype.message">20.5.3.2 Error.prototype.message</a></li><li><a href="fundamental-objects.html#sec-error.prototype.name" title="Error.prototype.name">20.5.3.3 Error.prototype.name</a></li><li><a href="fundamental-objects.html#sec-error.prototype.tostring" title="Error.prototype.toString ( )">20.5.3.4 Error.prototype.toString ( )</a></li></ol></li><li><a href="fundamental-objects.html#sec-properties-of-error-instances" title="Properties of Error Instances">20.5.4 Properties of Error Instances</a></li><li>+<a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard" title="Native Error Types Used in This Standard">20.5.5 Native Error Types Used in This Standard</a><ol class="toc"><li><a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard-evalerror" title="EvalError">20.5.5.1 EvalError</a></li><li><a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard-rangeerror" title="RangeError">20.5.5.2 RangeError</a></li><li><a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard-referenceerror" title="ReferenceError">20.5.5.3 ReferenceError</a></li><li><a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard-syntaxerror" title="SyntaxError">20.5.5.4 SyntaxError</a></li><li><a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard-typeerror" title="TypeError">20.5.5.5 TypeError</a></li><li><a href="fundamental-objects.html#sec-native-error-types-used-in-this-standard-urierror" title="URIError">20.5.5.6 URIError</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-nativeerror-object-structure" title="NativeError Object Structure">20.5.6 <var>NativeError</var> Object Structure</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-nativeerror-constructors" title="The NativeError Constructors">20.5.6.1 The <var>NativeError</var> Constructors</a><ol class="toc"><li><a href="fundamental-objects.html#sec-nativeerror" title="NativeError ( message [ , options ] )">20.5.6.1.1 <var>NativeError</var> ( <var>message</var> [ , <var>options</var> ] )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-nativeerror-constructors" title="Properties of the NativeError Constructors">20.5.6.2 Properties of the <var>NativeError</var> Constructors</a><ol class="toc"><li><a href="fundamental-objects.html#sec-nativeerror.prototype" title="NativeError.prototype">20.5.6.2.1 <var>NativeError</var>.prototype</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-nativeerror-prototype-objects" title="Properties of the NativeError Prototype Objects">20.5.6.3 Properties of the <var>NativeError</var> Prototype Objects</a><ol class="toc"><li><a href="fundamental-objects.html#sec-nativeerror.prototype.constructor" title="NativeError.prototype.constructor">20.5.6.3.1 <var>NativeError</var>.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-nativeerror.prototype.message" title="NativeError.prototype.message">20.5.6.3.2 <var>NativeError</var>.prototype.message</a></li><li><a href="fundamental-objects.html#sec-nativeerror.prototype.name" title="NativeError.prototype.name">20.5.6.3.3 <var>NativeError</var>.prototype.name</a></li></ol></li><li><a href="fundamental-objects.html#sec-properties-of-nativeerror-instances" title="Properties of NativeError Instances">20.5.6.4 Properties of <var>NativeError</var> Instances</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-aggregate-error-objects" title="AggregateError Objects">20.5.7 AggregateError Objects</a><ol class="toc"><li>+<a href="fundamental-objects.html#sec-aggregate-error-constructor" title="The AggregateError Constructor">20.5.7.1 The AggregateError Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-aggregate-error" title="AggregateError ( errors, message [ , options ] )">20.5.7.1.1 AggregateError ( <var>errors</var>, <var>message</var> [ , <var>options</var> ] )</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-aggregate-error-constructors" title="Properties of the AggregateError Constructor">20.5.7.2 Properties of the AggregateError Constructor</a><ol class="toc"><li><a href="fundamental-objects.html#sec-aggregate-error.prototype" title="AggregateError.prototype">20.5.7.2.1 AggregateError.prototype</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-properties-of-the-aggregate-error-prototype-objects" title="Properties of the AggregateError Prototype Object">20.5.7.3 Properties of the AggregateError Prototype Object</a><ol class="toc"><li><a href="fundamental-objects.html#sec-aggregate-error.prototype.constructor" title="AggregateError.prototype.constructor">20.5.7.3.1 AggregateError.prototype.constructor</a></li><li><a href="fundamental-objects.html#sec-aggregate-error.prototype.message" title="AggregateError.prototype.message">20.5.7.3.2 AggregateError.prototype.message</a></li><li><a href="fundamental-objects.html#sec-aggregate-error.prototype.name" title="AggregateError.prototype.name">20.5.7.3.3 AggregateError.prototype.name</a></li></ol></li><li><a href="fundamental-objects.html#sec-properties-of-aggregate-error-instances" title="Properties of AggregateError Instances">20.5.7.4 Properties of AggregateError Instances</a></li></ol></li><li>+<a href="fundamental-objects.html#sec-abstract-operations-for-error-objects" title="Abstract Operations for Error Objects">20.5.8 Abstract Operations for Error Objects</a><ol class="toc"><li><a href="fundamental-objects.html#sec-installerrorcause" title="InstallErrorCause ( O, options )">20.5.8.1 InstallErrorCause ( <var>O</var>, <var>options</var> )</a></li></ol></li></ol></li></ol></li><li>+<a href="numbers-and-dates.html#sec-numbers-and-dates" title="Numbers and Dates">21 Numbers and Dates</a><ol class="toc"><li>+<a href="numbers-and-dates.html#sec-number-objects" title="Number Objects">21.1 Number Objects</a><ol class="toc"><li>+<a href="numbers-and-dates.html#sec-number-constructor" title="The Number Constructor">21.1.1 The Number Constructor</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-number-constructor-number-value" title="Number ( value )">21.1.1.1 Number ( <var>value</var> )</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-properties-of-the-number-constructor" title="Properties of the Number Constructor">21.1.2 Properties of the Number Constructor</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-number.epsilon" title="Number.EPSILON">21.1.2.1 Number.EPSILON</a></li><li><a href="numbers-and-dates.html#sec-number.isfinite" title="Number.isFinite ( number )">21.1.2.2 Number.isFinite ( <var>number</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.isinteger" title="Number.isInteger ( number )">21.1.2.3 Number.isInteger ( <var>number</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.isnan" title="Number.isNaN ( number )">21.1.2.4 Number.isNaN ( <var>number</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.issafeinteger" title="Number.isSafeInteger ( number )">21.1.2.5 Number.isSafeInteger ( <var>number</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.max_safe_integer" title="Number.MAX_SAFE_INTEGER">21.1.2.6 Number.MAX_SAFE_INTEGER</a></li><li><a href="numbers-and-dates.html#sec-number.max_value" title="Number.MAX_VALUE">21.1.2.7 Number.MAX_VALUE</a></li><li><a href="numbers-and-dates.html#sec-number.min_safe_integer" title="Number.MIN_SAFE_INTEGER">21.1.2.8 Number.MIN_SAFE_INTEGER</a></li><li><a href="numbers-and-dates.html#sec-number.min_value" title="Number.MIN_VALUE">21.1.2.9 Number.MIN_VALUE</a></li><li><a href="numbers-and-dates.html#sec-number.nan" title="Number.NaN">21.1.2.10 Number.NaN</a></li><li><a href="numbers-and-dates.html#sec-number.negative_infinity" title="Number.NEGATIVE_INFINITY">21.1.2.11 Number.NEGATIVE_INFINITY</a></li><li><a href="numbers-and-dates.html#sec-number.parsefloat" title="Number.parseFloat ( string )">21.1.2.12 Number.parseFloat ( <var>string</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.parseint" title="Number.parseInt ( string, radix )">21.1.2.13 Number.parseInt ( <var>string</var>, <var>radix</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.positive_infinity" title="Number.POSITIVE_INFINITY">21.1.2.14 Number.POSITIVE_INFINITY</a></li><li><a href="numbers-and-dates.html#sec-number.prototype" title="Number.prototype">21.1.2.15 Number.prototype</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-properties-of-the-number-prototype-object" title="Properties of the Number Prototype Object">21.1.3 Properties of the Number Prototype Object</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-number.prototype.constructor" title="Number.prototype.constructor">21.1.3.1 Number.prototype.constructor</a></li><li><a href="numbers-and-dates.html#sec-number.prototype.toexponential" title="Number.prototype.toExponential ( fractionDigits )">21.1.3.2 Number.prototype.toExponential ( <var>fractionDigits</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.prototype.tofixed" title="Number.prototype.toFixed ( fractionDigits )">21.1.3.3 Number.prototype.toFixed ( <var>fractionDigits</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.prototype.tolocalestring" title="Number.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] )">21.1.3.4 Number.prototype.toLocaleString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-number.prototype.toprecision" title="Number.prototype.toPrecision ( precision )">21.1.3.5 Number.prototype.toPrecision ( <var>precision</var> )</a></li><li><a href="numbers-and-dates.html#sec-number.prototype.tostring" title="Number.prototype.toString ( [ radix ] )">21.1.3.6 Number.prototype.toString ( [ <var>radix</var> ] )</a></li><li>+<a href="numbers-and-dates.html#sec-number.prototype.valueof" title="Number.prototype.valueOf ( )">21.1.3.7 Number.prototype.valueOf ( )</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-thisnumbervalue" title="ThisNumberValue ( value )">21.1.3.7.1 ThisNumberValue ( <var>value</var> )</a></li></ol></li></ol></li><li><a href="numbers-and-dates.html#sec-properties-of-number-instances" title="Properties of Number Instances">21.1.4 Properties of Number Instances</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-bigint-objects" title="BigInt Objects">21.2 BigInt Objects</a><ol class="toc"><li>+<a href="numbers-and-dates.html#sec-bigint-constructor" title="The BigInt Constructor">21.2.1 The BigInt Constructor</a><ol class="toc"><li>+<a href="numbers-and-dates.html#sec-bigint-constructor-number-value" title="BigInt ( value )">21.2.1.1 BigInt ( <var>value</var> )</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-numbertobigint" title="NumberToBigInt ( number )">21.2.1.1.1 NumberToBigInt ( <var>number</var> )</a></li></ol></li></ol></li><li>+<a href="numbers-and-dates.html#sec-properties-of-the-bigint-constructor" title="Properties of the BigInt Constructor">21.2.2 Properties of the BigInt Constructor</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-bigint.asintn" title="BigInt.asIntN ( bits, bigint )">21.2.2.1 BigInt.asIntN ( <var>bits</var>, <var>bigint</var> )</a></li><li><a href="numbers-and-dates.html#sec-bigint.asuintn" title="BigInt.asUintN ( bits, bigint )">21.2.2.2 BigInt.asUintN ( <var>bits</var>, <var>bigint</var> )</a></li><li><a href="numbers-and-dates.html#sec-bigint.prototype" title="BigInt.prototype">21.2.2.3 BigInt.prototype</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-properties-of-the-bigint-prototype-object" title="Properties of the BigInt Prototype Object">21.2.3 Properties of the BigInt Prototype Object</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-bigint.prototype.constructor" title="BigInt.prototype.constructor">21.2.3.1 BigInt.prototype.constructor</a></li><li><a href="numbers-and-dates.html#sec-bigint.prototype.tolocalestring" title="BigInt.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] )">21.2.3.2 BigInt.prototype.toLocaleString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-bigint.prototype.tostring" title="BigInt.prototype.toString ( [ radix ] )">21.2.3.3 BigInt.prototype.toString ( [ <var>radix</var> ] )</a></li><li>+<a href="numbers-and-dates.html#sec-bigint.prototype.valueof" title="BigInt.prototype.valueOf ( )">21.2.3.4 BigInt.prototype.valueOf ( )</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-thisbigintvalue" title="ThisBigIntValue ( value )">21.2.3.4.1 ThisBigIntValue ( <var>value</var> )</a></li></ol></li><li><a href="numbers-and-dates.html#sec-bigint.prototype-%symbol.tostringtag%" title="BigInt.prototype [ %Symbol.toStringTag% ]">21.2.3.5 BigInt.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="numbers-and-dates.html#sec-properties-of-bigint-instances" title="Properties of BigInt Instances">21.2.4 Properties of BigInt Instances</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-math-object" title="The Math Object">21.3 The Math Object</a><ol class="toc"><li>+<a href="numbers-and-dates.html#sec-value-properties-of-the-math-object" title="Value Properties of the Math Object">21.3.1 Value Properties of the Math Object</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-math.e" title="Math.E">21.3.1.1 Math.E</a></li><li><a href="numbers-and-dates.html#sec-math.ln10" title="Math.LN10">21.3.1.2 Math.LN10</a></li><li><a href="numbers-and-dates.html#sec-math.ln2" title="Math.LN2">21.3.1.3 Math.LN2</a></li><li><a href="numbers-and-dates.html#sec-math.log10e" title="Math.LOG10E">21.3.1.4 Math.LOG10E</a></li><li><a href="numbers-and-dates.html#sec-math.log2e" title="Math.LOG2E">21.3.1.5 Math.LOG2E</a></li><li><a href="numbers-and-dates.html#sec-math.pi" title="Math.PI">21.3.1.6 Math.PI</a></li><li><a href="numbers-and-dates.html#sec-math.sqrt1_2" title="Math.SQRT1_2">21.3.1.7 Math.SQRT1_2</a></li><li><a href="numbers-and-dates.html#sec-math.sqrt2" title="Math.SQRT2">21.3.1.8 Math.SQRT2</a></li><li><a href="numbers-and-dates.html#sec-math-%symbol.tostringtag%" title="Math [ %Symbol.toStringTag% ]">21.3.1.9 Math [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-function-properties-of-the-math-object" title="Function Properties of the Math Object">21.3.2 Function Properties of the Math Object</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-math.abs" title="Math.abs ( x )">21.3.2.1 Math.abs ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.acos" title="Math.acos ( x )">21.3.2.2 Math.acos ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.acosh" title="Math.acosh ( x )">21.3.2.3 Math.acosh ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.asin" title="Math.asin ( x )">21.3.2.4 Math.asin ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.asinh" title="Math.asinh ( x )">21.3.2.5 Math.asinh ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.atan" title="Math.atan ( x )">21.3.2.6 Math.atan ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.atanh" title="Math.atanh ( x )">21.3.2.7 Math.atanh ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.atan2" title="Math.atan2 ( y, x )">21.3.2.8 Math.atan2 ( <var>y</var>, <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.cbrt" title="Math.cbrt ( x )">21.3.2.9 Math.cbrt ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.ceil" title="Math.ceil ( x )">21.3.2.10 Math.ceil ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.clz32" title="Math.clz32 ( x )">21.3.2.11 Math.clz32 ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.cos" title="Math.cos ( x )">21.3.2.12 Math.cos ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.cosh" title="Math.cosh ( x )">21.3.2.13 Math.cosh ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.exp" title="Math.exp ( x )">21.3.2.14 Math.exp ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.expm1" title="Math.expm1 ( x )">21.3.2.15 Math.expm1 ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.floor" title="Math.floor ( x )">21.3.2.16 Math.floor ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.fround" title="Math.fround ( x )">21.3.2.17 Math.fround ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.hypot" title="Math.hypot ( ...args )">21.3.2.18 Math.hypot ( ...<var>args</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.imul" title="Math.imul ( x, y )">21.3.2.19 Math.imul ( <var>x</var>, <var>y</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.log" title="Math.log ( x )">21.3.2.20 Math.log ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.log1p" title="Math.log1p ( x )">21.3.2.21 Math.log1p ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.log10" title="Math.log10 ( x )">21.3.2.22 Math.log10 ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.log2" title="Math.log2 ( x )">21.3.2.23 Math.log2 ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.max" title="Math.max ( ...args )">21.3.2.24 Math.max ( ...<var>args</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.min" title="Math.min ( ...args )">21.3.2.25 Math.min ( ...<var>args</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.pow" title="Math.pow ( base, exponent )">21.3.2.26 Math.pow ( <var>base</var>, <var>exponent</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.random" title="Math.random ( )">21.3.2.27 Math.random ( )</a></li><li><a href="numbers-and-dates.html#sec-math.round" title="Math.round ( x )">21.3.2.28 Math.round ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.sign" title="Math.sign ( x )">21.3.2.29 Math.sign ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.sin" title="Math.sin ( x )">21.3.2.30 Math.sin ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.sinh" title="Math.sinh ( x )">21.3.2.31 Math.sinh ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.sqrt" title="Math.sqrt ( x )">21.3.2.32 Math.sqrt ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.tan" title="Math.tan ( x )">21.3.2.33 Math.tan ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.tanh" title="Math.tanh ( x )">21.3.2.34 Math.tanh ( <var>x</var> )</a></li><li><a href="numbers-and-dates.html#sec-math.trunc" title="Math.trunc ( x )">21.3.2.35 Math.trunc ( <var>x</var> )</a></li></ol></li></ol></li><li>+<a href="numbers-and-dates.html#sec-date-objects" title="Date Objects">21.4 Date Objects</a><ol class="toc"><li>+<a href="numbers-and-dates.html#sec-overview-of-date-objects-and-definitions-of-abstract-operations" title="Overview of Date Objects and Definitions of Abstract Operations">21.4.1 Overview of Date Objects and Definitions of Abstract Operations</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-time-values-and-time-range" title="Time Values and Time Range">21.4.1.1 Time Values and Time Range</a></li><li><a href="numbers-and-dates.html#sec-time-related-constants" title="Time-related Constants">21.4.1.2 Time-related Constants</a></li><li><a href="numbers-and-dates.html#sec-day" title="Day ( t )">21.4.1.3 Day ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-timewithinday" title="TimeWithinDay ( t )">21.4.1.4 TimeWithinDay ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-daysinyear" title="DaysInYear ( y )">21.4.1.5 DaysInYear ( <var>y</var> )</a></li><li><a href="numbers-and-dates.html#sec-dayfromyear" title="DayFromYear ( y )">21.4.1.6 DayFromYear ( <var>y</var> )</a></li><li><a href="numbers-and-dates.html#sec-timefromyear" title="TimeFromYear ( y )">21.4.1.7 TimeFromYear ( <var>y</var> )</a></li><li><a href="numbers-and-dates.html#sec-yearfromtime" title="YearFromTime ( t )">21.4.1.8 YearFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-daywithinyear" title="DayWithinYear ( t )">21.4.1.9 DayWithinYear ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-inleapyear" title="InLeapYear ( t )">21.4.1.10 InLeapYear ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-monthfromtime" title="MonthFromTime ( t )">21.4.1.11 MonthFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-datefromtime" title="DateFromTime ( t )">21.4.1.12 DateFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-weekday" title="WeekDay ( t )">21.4.1.13 WeekDay ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-hourfromtime" title="HourFromTime ( t )">21.4.1.14 HourFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-minfromtime" title="MinFromTime ( t )">21.4.1.15 MinFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-secfromtime" title="SecFromTime ( t )">21.4.1.16 SecFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-msfromtime" title="msFromTime ( t )">21.4.1.17 msFromTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-getutcepochnanoseconds" title="GetUTCEpochNanoseconds ( year, month, day, hour, minute, second, millisecond, microsecond, nanosecond )">21.4.1.18 GetUTCEpochNanoseconds ( <var>year</var>, <var>month</var>, <var>day</var>, <var>hour</var>, <var>minute</var>, <var>second</var>, <var>millisecond</var>, <var>microsecond</var>, <var>nanosecond</var> )</a></li><li><a href="numbers-and-dates.html#sec-time-zone-identifiers" title="Time Zone Identifiers">21.4.1.19 Time Zone Identifiers</a></li><li><a href="numbers-and-dates.html#sec-getnamedtimezoneepochnanoseconds" title="GetNamedTimeZoneEpochNanoseconds ( timeZoneIdentifier, year, month, day, hour, minute, second, millisecond, microsecond, nanosecond )">21.4.1.20 GetNamedTimeZoneEpochNanoseconds ( <var>timeZoneIdentifier</var>, <var>year</var>, <var>month</var>, <var>day</var>, <var>hour</var>, <var>minute</var>, <var>second</var>, <var>millisecond</var>, <var>microsecond</var>, <var>nanosecond</var> )</a></li><li><a href="numbers-and-dates.html#sec-getnamedtimezoneoffsetnanoseconds" title="GetNamedTimeZoneOffsetNanoseconds ( timeZoneIdentifier, epochNanoseconds )">21.4.1.21 GetNamedTimeZoneOffsetNanoseconds ( <var>timeZoneIdentifier</var>, <var>epochNanoseconds</var> )</a></li><li><a href="numbers-and-dates.html#sec-time-zone-identifier-record" title="Time Zone Identifier Record">21.4.1.22 Time Zone Identifier Record</a></li><li><a href="numbers-and-dates.html#sec-availablenamedtimezoneidentifiers" title="AvailableNamedTimeZoneIdentifiers ( )">21.4.1.23 AvailableNamedTimeZoneIdentifiers ( )</a></li><li><a href="numbers-and-dates.html#sec-systemtimezoneidentifier" title="SystemTimeZoneIdentifier ( )">21.4.1.24 SystemTimeZoneIdentifier ( )</a></li><li><a href="numbers-and-dates.html#sec-localtime" title="LocalTime ( t )">21.4.1.25 LocalTime ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-utc-t" title="UTC ( t )">21.4.1.26 UTC ( <var>t</var> )</a></li><li><a href="numbers-and-dates.html#sec-maketime" title="MakeTime ( hour, min, sec, ms )">21.4.1.27 MakeTime ( <var>hour</var>, <var>min</var>, <var>sec</var>, <var>ms</var> )</a></li><li><a href="numbers-and-dates.html#sec-makeday" title="MakeDay ( year, month, date )">21.4.1.28 MakeDay ( <var>year</var>, <var>month</var>, <var>date</var> )</a></li><li><a href="numbers-and-dates.html#sec-makedate" title="MakeDate ( day, time )">21.4.1.29 MakeDate ( <var>day</var>, <var>time</var> )</a></li><li><a href="numbers-and-dates.html#sec-makefullyear" title="MakeFullYear ( year )">21.4.1.30 MakeFullYear ( <var>year</var> )</a></li><li><a href="numbers-and-dates.html#sec-timeclip" title="TimeClip ( time )">21.4.1.31 TimeClip ( <var>time</var> )</a></li><li>+<a href="numbers-and-dates.html#sec-date-time-string-format" title="Date Time String Format">21.4.1.32 Date Time String Format</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-expanded-years" title="Expanded Years">21.4.1.32.1 Expanded Years</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-time-zone-offset-strings" title="Time Zone Offset String Format">21.4.1.33 Time Zone Offset String Format</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-istimezoneoffsetstring" title="IsTimeZoneOffsetString ( offsetString )">21.4.1.33.1 IsTimeZoneOffsetString ( <var>offsetString</var> )</a></li><li><a href="numbers-and-dates.html#sec-parsetimezoneoffsetstring" title="ParseTimeZoneOffsetString ( offsetString )">21.4.1.33.2 ParseTimeZoneOffsetString ( <var>offsetString</var> )</a></li></ol></li></ol></li><li>+<a href="numbers-and-dates.html#sec-date-constructor" title="The Date Constructor">21.4.2 The Date Constructor</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-date" title="Date ( ...values )">21.4.2.1 Date ( ...<var>values</var> )</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-properties-of-the-date-constructor" title="Properties of the Date Constructor">21.4.3 Properties of the Date Constructor</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-date.now" title="Date.now ( )">21.4.3.1 Date.now ( )</a></li><li><a href="numbers-and-dates.html#sec-date.parse" title="Date.parse ( string )">21.4.3.2 Date.parse ( <var>string</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype" title="Date.prototype">21.4.3.3 Date.prototype</a></li><li><a href="numbers-and-dates.html#sec-date.utc" title="Date.UTC ( year [ , month [ , date [ , hours [ , minutes [ , seconds [ , ms ] ] ] ] ] ] )">21.4.3.4 Date.UTC ( <var>year</var> [ , <var>month</var> [ , <var>date</var> [ , <var>hours</var> [ , <var>minutes</var> [ , <var>seconds</var> [ , <var>ms</var> ] ] ] ] ] ] )</a></li></ol></li><li>+<a href="numbers-and-dates.html#sec-properties-of-the-date-prototype-object" title="Properties of the Date Prototype Object">21.4.4 Properties of the Date Prototype Object</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-date.prototype.constructor" title="Date.prototype.constructor">21.4.4.1 Date.prototype.constructor</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getdate" title="Date.prototype.getDate ( )">21.4.4.2 Date.prototype.getDate ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getday" title="Date.prototype.getDay ( )">21.4.4.3 Date.prototype.getDay ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getfullyear" title="Date.prototype.getFullYear ( )">21.4.4.4 Date.prototype.getFullYear ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.gethours" title="Date.prototype.getHours ( )">21.4.4.5 Date.prototype.getHours ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getmilliseconds" title="Date.prototype.getMilliseconds ( )">21.4.4.6 Date.prototype.getMilliseconds ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getminutes" title="Date.prototype.getMinutes ( )">21.4.4.7 Date.prototype.getMinutes ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getmonth" title="Date.prototype.getMonth ( )">21.4.4.8 Date.prototype.getMonth ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getseconds" title="Date.prototype.getSeconds ( )">21.4.4.9 Date.prototype.getSeconds ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.gettime" title="Date.prototype.getTime ( )">21.4.4.10 Date.prototype.getTime ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.gettimezoneoffset" title="Date.prototype.getTimezoneOffset ( )">21.4.4.11 Date.prototype.getTimezoneOffset ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcdate" title="Date.prototype.getUTCDate ( )">21.4.4.12 Date.prototype.getUTCDate ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcday" title="Date.prototype.getUTCDay ( )">21.4.4.13 Date.prototype.getUTCDay ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcfullyear" title="Date.prototype.getUTCFullYear ( )">21.4.4.14 Date.prototype.getUTCFullYear ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutchours" title="Date.prototype.getUTCHours ( )">21.4.4.15 Date.prototype.getUTCHours ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcmilliseconds" title="Date.prototype.getUTCMilliseconds ( )">21.4.4.16 Date.prototype.getUTCMilliseconds ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcminutes" title="Date.prototype.getUTCMinutes ( )">21.4.4.17 Date.prototype.getUTCMinutes ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcmonth" title="Date.prototype.getUTCMonth ( )">21.4.4.18 Date.prototype.getUTCMonth ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.getutcseconds" title="Date.prototype.getUTCSeconds ( )">21.4.4.19 Date.prototype.getUTCSeconds ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setdate" title="Date.prototype.setDate ( date )">21.4.4.20 Date.prototype.setDate ( <var>date</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setfullyear" title="Date.prototype.setFullYear ( year [ , month [ , date ] ] )">21.4.4.21 Date.prototype.setFullYear ( <var>year</var> [ , <var>month</var> [ , <var>date</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.sethours" title="Date.prototype.setHours ( hour [ , min [ , sec [ , ms ] ] ] )">21.4.4.22 Date.prototype.setHours ( <var>hour</var> [ , <var>min</var> [ , <var>sec</var> [ , <var>ms</var> ] ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setmilliseconds" title="Date.prototype.setMilliseconds ( ms )">21.4.4.23 Date.prototype.setMilliseconds ( <var>ms</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setminutes" title="Date.prototype.setMinutes ( min [ , sec [ , ms ] ] )">21.4.4.24 Date.prototype.setMinutes ( <var>min</var> [ , <var>sec</var> [ , <var>ms</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setmonth" title="Date.prototype.setMonth ( month [ , date ] )">21.4.4.25 Date.prototype.setMonth ( <var>month</var> [ , <var>date</var> ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setseconds" title="Date.prototype.setSeconds ( sec [ , ms ] )">21.4.4.26 Date.prototype.setSeconds ( <var>sec</var> [ , <var>ms</var> ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.settime" title="Date.prototype.setTime ( time )">21.4.4.27 Date.prototype.setTime ( <var>time</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutcdate" title="Date.prototype.setUTCDate ( date )">21.4.4.28 Date.prototype.setUTCDate ( <var>date</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutcfullyear" title="Date.prototype.setUTCFullYear ( year [ , month [ , date ] ] )">21.4.4.29 Date.prototype.setUTCFullYear ( <var>year</var> [ , <var>month</var> [ , <var>date</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutchours" title="Date.prototype.setUTCHours ( hour [ , min [ , sec [ , ms ] ] ] )">21.4.4.30 Date.prototype.setUTCHours ( <var>hour</var> [ , <var>min</var> [ , <var>sec</var> [ , <var>ms</var> ] ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutcmilliseconds" title="Date.prototype.setUTCMilliseconds ( ms )">21.4.4.31 Date.prototype.setUTCMilliseconds ( <var>ms</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutcminutes" title="Date.prototype.setUTCMinutes ( min [ , sec [ , ms ] ] )">21.4.4.32 Date.prototype.setUTCMinutes ( <var>min</var> [ , <var>sec</var> [ , <var>ms</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutcmonth" title="Date.prototype.setUTCMonth ( month [ , date ] )">21.4.4.33 Date.prototype.setUTCMonth ( <var>month</var> [ , <var>date</var> ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.setutcseconds" title="Date.prototype.setUTCSeconds ( sec [ , ms ] )">21.4.4.34 Date.prototype.setUTCSeconds ( <var>sec</var> [ , <var>ms</var> ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.todatestring" title="Date.prototype.toDateString ( )">21.4.4.35 Date.prototype.toDateString ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.toisostring" title="Date.prototype.toISOString ( )">21.4.4.36 Date.prototype.toISOString ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.tojson" title="Date.prototype.toJSON ( key )">21.4.4.37 Date.prototype.toJSON ( <var>key</var> )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.tolocaledatestring" title="Date.prototype.toLocaleDateString ( [ reserved1 [ , reserved2 ] ] )">21.4.4.38 Date.prototype.toLocaleDateString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.tolocalestring" title="Date.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] )">21.4.4.39 Date.prototype.toLocaleString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.tolocaletimestring" title="Date.prototype.toLocaleTimeString ( [ reserved1 [ , reserved2 ] ] )">21.4.4.40 Date.prototype.toLocaleTimeString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li>+<a href="numbers-and-dates.html#sec-date.prototype.tostring" title="Date.prototype.toString ( )">21.4.4.41 Date.prototype.toString ( )</a><ol class="toc"><li><a href="numbers-and-dates.html#sec-timestring" title="TimeString ( tv )">21.4.4.41.1 TimeString ( <var>tv</var> )</a></li><li><a href="numbers-and-dates.html#sec-datestring" title="DateString ( tv )">21.4.4.41.2 DateString ( <var>tv</var> )</a></li><li><a href="numbers-and-dates.html#sec-timezoneestring" title="TimeZoneString ( tv )">21.4.4.41.3 TimeZoneString ( <var>tv</var> )</a></li><li><a href="numbers-and-dates.html#sec-todatestring" title="ToDateString ( tv )">21.4.4.41.4 ToDateString ( <var>tv</var> )</a></li></ol></li><li><a href="numbers-and-dates.html#sec-date.prototype.totimestring" title="Date.prototype.toTimeString ( )">21.4.4.42 Date.prototype.toTimeString ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.toutcstring" title="Date.prototype.toUTCString ( )">21.4.4.43 Date.prototype.toUTCString ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype.valueof" title="Date.prototype.valueOf ( )">21.4.4.44 Date.prototype.valueOf ( )</a></li><li><a href="numbers-and-dates.html#sec-date.prototype-%symbol.toprimitive%" title="Date.prototype [ %Symbol.toPrimitive% ] ( hint )">21.4.4.45 Date.prototype [ %Symbol.toPrimitive% ] ( <var>hint</var> )</a></li></ol></li><li><a href="numbers-and-dates.html#sec-properties-of-date-instances" title="Properties of Date Instances">21.4.5 Properties of Date Instances</a></li></ol></li></ol></li><li>+<a href="text-processing.html#sec-text-processing" title="Text Processing">22 Text Processing</a><ol class="toc"><li>+<a href="text-processing.html#sec-string-objects" title="String Objects">22.1 String Objects</a><ol class="toc"><li>+<a href="text-processing.html#sec-string-constructor" title="The String Constructor">22.1.1 The String Constructor</a><ol class="toc"><li><a href="text-processing.html#sec-string-constructor-string-value" title="String ( value )">22.1.1.1 String ( <var>value</var> )</a></li></ol></li><li>+<a href="text-processing.html#sec-properties-of-the-string-constructor" title="Properties of the String Constructor">22.1.2 Properties of the String Constructor</a><ol class="toc"><li><a href="text-processing.html#sec-string.fromcharcode" title="String.fromCharCode ( ...codeUnits )">22.1.2.1 String.fromCharCode ( ...<var>codeUnits</var> )</a></li><li><a href="text-processing.html#sec-string.fromcodepoint" title="String.fromCodePoint ( ...codePoints )">22.1.2.2 String.fromCodePoint ( ...<var>codePoints</var> )</a></li><li><a href="text-processing.html#sec-string.prototype" title="String.prototype">22.1.2.3 String.prototype</a></li><li><a href="text-processing.html#sec-string.raw" title="String.raw ( template, ...substitutions )">22.1.2.4 String.raw ( <var>template</var>, ...<var>substitutions</var> )</a></li></ol></li><li>+<a href="text-processing.html#sec-properties-of-the-string-prototype-object" title="Properties of the String Prototype Object">22.1.3 Properties of the String Prototype Object</a><ol class="toc"><li><a href="text-processing.html#sec-string.prototype.at" title="String.prototype.at ( index )">22.1.3.1 String.prototype.at ( <var>index</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.charat" title="String.prototype.charAt ( pos )">22.1.3.2 String.prototype.charAt ( <var>pos</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.charcodeat" title="String.prototype.charCodeAt ( pos )">22.1.3.3 String.prototype.charCodeAt ( <var>pos</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.codepointat" title="String.prototype.codePointAt ( pos )">22.1.3.4 String.prototype.codePointAt ( <var>pos</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.concat" title="String.prototype.concat ( ...args )">22.1.3.5 String.prototype.concat ( ...<var>args</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.constructor" title="String.prototype.constructor">22.1.3.6 String.prototype.constructor</a></li><li><a href="text-processing.html#sec-string.prototype.endswith" title="String.prototype.endsWith ( searchString [ , endPosition ] )">22.1.3.7 String.prototype.endsWith ( <var>searchString</var> [ , <var>endPosition</var> ] )</a></li><li><a href="text-processing.html#sec-string.prototype.includes" title="String.prototype.includes ( searchString [ , position ] )">22.1.3.8 String.prototype.includes ( <var>searchString</var> [ , <var>position</var> ] )</a></li><li><a href="text-processing.html#sec-string.prototype.indexof" title="String.prototype.indexOf ( searchString [ , position ] )">22.1.3.9 String.prototype.indexOf ( <var>searchString</var> [ , <var>position</var> ] )</a></li><li><a href="text-processing.html#sec-string.prototype.iswellformed" title="String.prototype.isWellFormed ( )">22.1.3.10 String.prototype.isWellFormed ( )</a></li><li><a href="text-processing.html#sec-string.prototype.lastindexof" title="String.prototype.lastIndexOf ( searchString [ , position ] )">22.1.3.11 String.prototype.lastIndexOf ( <var>searchString</var> [ , <var>position</var> ] )</a></li><li><a href="text-processing.html#sec-string.prototype.localecompare" title="String.prototype.localeCompare ( that [ , reserved1 [ , reserved2 ] ] )">22.1.3.12 String.prototype.localeCompare ( <var>that</var> [ , <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="text-processing.html#sec-string.prototype.match" title="String.prototype.match ( regexp )">22.1.3.13 String.prototype.match ( <var>regexp</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.matchall" title="String.prototype.matchAll ( regexp )">22.1.3.14 String.prototype.matchAll ( <var>regexp</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.normalize" title="String.prototype.normalize ( [ form ] )">22.1.3.15 String.prototype.normalize ( [ <var>form</var> ] )</a></li><li><a href="text-processing.html#sec-string.prototype.padend" title="String.prototype.padEnd ( maxLength [ , fillString ] )">22.1.3.16 String.prototype.padEnd ( <var>maxLength</var> [ , <var>fillString</var> ] )</a></li><li>+<a href="text-processing.html#sec-string.prototype.padstart" title="String.prototype.padStart ( maxLength [ , fillString ] )">22.1.3.17 String.prototype.padStart ( <var>maxLength</var> [ , <var>fillString</var> ] )</a><ol class="toc"><li><a href="text-processing.html#sec-stringpaddingbuiltinsimpl" title="StringPaddingBuiltinsImpl ( O, maxLength, fillString, placement )">22.1.3.17.1 StringPaddingBuiltinsImpl ( <var>O</var>, <var>maxLength</var>, <var>fillString</var>, <var>placement</var> )</a></li><li><a href="text-processing.html#sec-stringpad" title="StringPad ( S, maxLength, fillString, placement )">22.1.3.17.2 StringPad ( <var>S</var>, <var>maxLength</var>, <var>fillString</var>, <var>placement</var> )</a></li><li><a href="text-processing.html#sec-tozeropaddeddecimalstring" title="ToZeroPaddedDecimalString ( n, minLength )">22.1.3.17.3 ToZeroPaddedDecimalString ( <var>n</var>, <var>minLength</var> )</a></li></ol></li><li><a href="text-processing.html#sec-string.prototype.repeat" title="String.prototype.repeat ( count )">22.1.3.18 String.prototype.repeat ( <var>count</var> )</a></li><li>+<a href="text-processing.html#sec-string.prototype.replace" title="String.prototype.replace ( searchValue, replaceValue )">22.1.3.19 String.prototype.replace ( <var>searchValue</var>, <var>replaceValue</var> )</a><ol class="toc"><li><a href="text-processing.html#sec-getsubstitution" title="GetSubstitution ( matched, str, position, captures, namedCaptures, replacementTemplate )">22.1.3.19.1 GetSubstitution ( <var>matched</var>, <var>str</var>, <var>position</var>, <var>captures</var>, <var>namedCaptures</var>, <var>replacementTemplate</var> )</a></li></ol></li><li><a href="text-processing.html#sec-string.prototype.replaceall" title="String.prototype.replaceAll ( searchValue, replaceValue )">22.1.3.20 String.prototype.replaceAll ( <var>searchValue</var>, <var>replaceValue</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.search" title="String.prototype.search ( regexp )">22.1.3.21 String.prototype.search ( <var>regexp</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.slice" title="String.prototype.slice ( start, end )">22.1.3.22 String.prototype.slice ( <var>start</var>, <var>end</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.split" title="String.prototype.split ( separator, limit )">22.1.3.23 String.prototype.split ( <var>separator</var>, <var>limit</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.startswith" title="String.prototype.startsWith ( searchString [ , position ] )">22.1.3.24 String.prototype.startsWith ( <var>searchString</var> [ , <var>position</var> ] )</a></li><li><a href="text-processing.html#sec-string.prototype.substring" title="String.prototype.substring ( start, end )">22.1.3.25 String.prototype.substring ( <var>start</var>, <var>end</var> )</a></li><li><a href="text-processing.html#sec-string.prototype.tolocalelowercase" title="String.prototype.toLocaleLowerCase ( [ reserved1 [ , reserved2 ] ] )">22.1.3.26 String.prototype.toLocaleLowerCase ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="text-processing.html#sec-string.prototype.tolocaleuppercase" title="String.prototype.toLocaleUpperCase ( [ reserved1 [ , reserved2 ] ] )">22.1.3.27 String.prototype.toLocaleUpperCase ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="text-processing.html#sec-string.prototype.tolowercase" title="String.prototype.toLowerCase ( )">22.1.3.28 String.prototype.toLowerCase ( )</a></li><li><a href="text-processing.html#sec-string.prototype.tostring" title="String.prototype.toString ( )">22.1.3.29 String.prototype.toString ( )</a></li><li><a href="text-processing.html#sec-string.prototype.touppercase" title="String.prototype.toUpperCase ( )">22.1.3.30 String.prototype.toUpperCase ( )</a></li><li><a href="text-processing.html#sec-string.prototype.towellformed" title="String.prototype.toWellFormed ( )">22.1.3.31 String.prototype.toWellFormed ( )</a></li><li>+<a href="text-processing.html#sec-string.prototype.trim" title="String.prototype.trim ( )">22.1.3.32 String.prototype.trim ( )</a><ol class="toc"><li><a href="text-processing.html#sec-trimstring" title="TrimString ( string, where )">22.1.3.32.1 TrimString ( <var>string</var>, <var>where</var> )</a></li></ol></li><li><a href="text-processing.html#sec-string.prototype.trimend" title="String.prototype.trimEnd ( )">22.1.3.33 String.prototype.trimEnd ( )</a></li><li><a href="text-processing.html#sec-string.prototype.trimstart" title="String.prototype.trimStart ( )">22.1.3.34 String.prototype.trimStart ( )</a></li><li>+<a href="text-processing.html#sec-string.prototype.valueof" title="String.prototype.valueOf ( )">22.1.3.35 String.prototype.valueOf ( )</a><ol class="toc"><li><a href="text-processing.html#sec-thisstringvalue" title="ThisStringValue ( value )">22.1.3.35.1 ThisStringValue ( <var>value</var> )</a></li></ol></li><li><a href="text-processing.html#sec-string.prototype-%symbol.iterator%" title="String.prototype [ %Symbol.iterator% ] ( )">22.1.3.36 String.prototype [ %Symbol.iterator% ] ( )</a></li></ol></li><li>+<a href="text-processing.html#sec-properties-of-string-instances" title="Properties of String Instances">22.1.4 Properties of String Instances</a><ol class="toc"><li><a href="text-processing.html#sec-properties-of-string-instances-length" title="length">22.1.4.1 length</a></li></ol></li><li>+<a href="text-processing.html#sec-string-iterator-objects" title="String Iterator Objects">22.1.5 String Iterator Objects</a><ol class="toc"><li>+<a href="text-processing.html#sec-%stringiteratorprototype%-object" title="The %StringIteratorPrototype% Object">22.1.5.1 The %StringIteratorPrototype% Object</a><ol class="toc"><li><a href="text-processing.html#sec-%stringiteratorprototype%.next" title="%StringIteratorPrototype%.next ( )">22.1.5.1.1 %StringIteratorPrototype%.next ( )</a></li><li><a href="text-processing.html#sec-%stringiteratorprototype%-%symbol.tostringtag%" title="%StringIteratorPrototype% [ %Symbol.toStringTag% ]">22.1.5.1.2 %StringIteratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li></ol></li><li>+<a href="text-processing.html#sec-regexp-regular-expression-objects" title="RegExp (Regular Expression) Objects">22.2 RegExp (Regular Expression) Objects</a><ol class="toc"><li>+<a href="text-processing.html#sec-patterns" title="Patterns">22.2.1 Patterns</a><ol class="toc"><li><a href="text-processing.html#sec-patterns-static-semantics-early-errors" title="Static Semantics: Early Errors">22.2.1.1 SS: Early Errors</a></li><li><a href="text-processing.html#sec-countleftcapturingparenswithin" title="Static Semantics: CountLeftCapturingParensWithin ( node )">22.2.1.2 SS: CountLeftCapturingParensWithin ( <var>node</var> )</a></li><li><a href="text-processing.html#sec-countleftcapturingparensbefore" title="Static Semantics: CountLeftCapturingParensBefore ( node )">22.2.1.3 SS: CountLeftCapturingParensBefore ( <var>node</var> )</a></li><li><a href="text-processing.html#sec-mightbothparticipate" title="Static Semantics: MightBothParticipate ( x, y )">22.2.1.4 SS: MightBothParticipate ( <var>x</var>, <var>y</var> )</a></li><li><a href="text-processing.html#sec-patterns-static-semantics-capturing-group-number" title="Static Semantics: CapturingGroupNumber">22.2.1.5 SS: CapturingGroupNumber</a></li><li><a href="text-processing.html#sec-patterns-static-semantics-is-character-class" title="Static Semantics: IsCharacterClass">22.2.1.6 SS: IsCharacterClass</a></li><li><a href="text-processing.html#sec-patterns-static-semantics-character-value" title="Static Semantics: CharacterValue">22.2.1.7 SS: CharacterValue</a></li><li><a href="text-processing.html#sec-static-semantics-maycontainstrings" title="Static Semantics: MayContainStrings">22.2.1.8 SS: MayContainStrings</a></li><li><a href="text-processing.html#sec-groupspecifiersthatmatch" title="Static Semantics: GroupSpecifiersThatMatch ( thisGroupName )">22.2.1.9 SS: GroupSpecifiersThatMatch ( <var>thisGroupName</var> )</a></li><li><a href="text-processing.html#sec-static-semantics-capturinggroupname" title="Static Semantics: CapturingGroupName">22.2.1.10 SS: CapturingGroupName</a></li><li><a href="text-processing.html#sec-regexpidentifiercodepoints" title="Static Semantics: RegExpIdentifierCodePoints">22.2.1.11 SS: RegExpIdentifierCodePoints</a></li><li><a href="text-processing.html#sec-regexpidentifiercodepoint" title="Static Semantics: RegExpIdentifierCodePoint">22.2.1.12 SS: RegExpIdentifierCodePoint</a></li></ol></li><li>+<a href="text-processing.html#sec-pattern-semantics" title="Pattern Semantics">22.2.2 Pattern Semantics</a><ol class="toc"><li>+<a href="text-processing.html#sec-pattern-notation" title="Notation">22.2.2.1 Notation</a><ol class="toc"><li><a href="text-processing.html#sec-regexp-records" title="RegExp Records">22.2.2.1.1 RegExp Records</a></li></ol></li><li><a href="text-processing.html#sec-compilepattern" title="Runtime Semantics: CompilePattern">22.2.2.2 RS: CompilePattern</a></li><li>+<a href="text-processing.html#sec-compilesubpattern" title="Runtime Semantics: CompileSubpattern">22.2.2.3 RS: CompileSubpattern</a><ol class="toc"><li><a href="text-processing.html#sec-runtime-semantics-repeatmatcher-abstract-operation" title="RepeatMatcher ( m, min, max, greedy, x, c, parenIndex, parenCount )">22.2.2.3.1 RepeatMatcher ( <var>m</var>, <var>min</var>, <var>max</var>, <var>greedy</var>, <var>x</var>, <var>c</var>, <var>parenIndex</var>, <var>parenCount</var> )</a></li><li><a href="text-processing.html#sec-emptymatcher" title="EmptyMatcher ( )">22.2.2.3.2 EmptyMatcher ( )</a></li><li><a href="text-processing.html#sec-matchtwoalternatives" title="MatchTwoAlternatives ( m1, m2 )">22.2.2.3.3 MatchTwoAlternatives ( <var>m1</var>, <var>m2</var> )</a></li><li><a href="text-processing.html#sec-matchsequence" title="MatchSequence ( m1, m2, direction )">22.2.2.3.4 MatchSequence ( <var>m1</var>, <var>m2</var>, <var>direction</var> )</a></li></ol></li><li>+<a href="text-processing.html#sec-compileassertion" title="Runtime Semantics: CompileAssertion">22.2.2.4 RS: CompileAssertion</a><ol class="toc"><li><a href="text-processing.html#sec-runtime-semantics-iswordchar-abstract-operation" title="IsWordChar ( rer, Input, e )">22.2.2.4.1 IsWordChar ( <var>rer</var>, <var>Input</var>, <var>e</var> )</a></li></ol></li><li><a href="text-processing.html#sec-compilequantifier" title="Runtime Semantics: CompileQuantifier">22.2.2.5 RS: CompileQuantifier</a></li><li><a href="text-processing.html#sec-compilequantifierprefix" title="Runtime Semantics: CompileQuantifierPrefix">22.2.2.6 RS: CompileQuantifierPrefix</a></li><li>+<a href="text-processing.html#sec-compileatom" title="Runtime Semantics: CompileAtom">22.2.2.7 RS: CompileAtom</a><ol class="toc"><li><a href="text-processing.html#sec-runtime-semantics-charactersetmatcher-abstract-operation" title="CharacterSetMatcher ( rer, A, invert, direction )">22.2.2.7.1 CharacterSetMatcher ( <var>rer</var>, <var>A</var>, <var>invert</var>, <var>direction</var> )</a></li><li><a href="text-processing.html#sec-backreference-matcher" title="BackreferenceMatcher ( rer, ns, direction )">22.2.2.7.2 BackreferenceMatcher ( <var>rer</var>, <var>ns</var>, <var>direction</var> )</a></li><li><a href="text-processing.html#sec-runtime-semantics-canonicalize-ch" title="Canonicalize ( rer, ch )">22.2.2.7.3 Canonicalize ( <var>rer</var>, <var>ch</var> )</a></li></ol></li><li><a href="text-processing.html#sec-compilecharacterclass" title="Runtime Semantics: CompileCharacterClass">22.2.2.8 RS: CompileCharacterClass</a></li><li>+<a href="text-processing.html#sec-compiletocharset" title="Runtime Semantics: CompileToCharSet">22.2.2.9 RS: CompileToCharSet</a><ol class="toc"><li><a href="text-processing.html#sec-runtime-semantics-characterrange-abstract-operation" title="CharacterRange ( A, B )">22.2.2.9.1 CharacterRange ( <var>A</var>, <var>B</var> )</a></li><li><a href="text-processing.html#sec-runtime-semantics-haseitherunicodeflag-abstract-operation" title="HasEitherUnicodeFlag ( rer )">22.2.2.9.2 HasEitherUnicodeFlag ( <var>rer</var> )</a></li><li><a href="text-processing.html#sec-wordcharacters" title="WordCharacters ( rer )">22.2.2.9.3 WordCharacters ( <var>rer</var> )</a></li><li><a href="text-processing.html#sec-allcharacters" title="AllCharacters ( rer )">22.2.2.9.4 AllCharacters ( <var>rer</var> )</a></li><li><a href="text-processing.html#sec-maybesimplecasefolding" title="MaybeSimpleCaseFolding ( rer, A )">22.2.2.9.5 MaybeSimpleCaseFolding ( <var>rer</var>, <var>A</var> )</a></li><li><a href="text-processing.html#sec-charactercomplement" title="CharacterComplement ( rer, S )">22.2.2.9.6 CharacterComplement ( <var>rer</var>, <var>S</var> )</a></li><li><a href="text-processing.html#sec-runtime-semantics-unicodematchproperty-p" title="UnicodeMatchProperty ( rer, p )">22.2.2.9.7 UnicodeMatchProperty ( <var>rer</var>, <var>p</var> )</a></li><li><a href="text-processing.html#sec-runtime-semantics-unicodematchpropertyvalue-p-v" title="UnicodeMatchPropertyValue ( p, v )">22.2.2.9.8 UnicodeMatchPropertyValue ( <var>p</var>, <var>v</var> )</a></li></ol></li><li><a href="text-processing.html#sec-compileclasssetstring" title="Runtime Semantics: CompileClassSetString">22.2.2.10 RS: CompileClassSetString</a></li></ol></li><li>+<a href="text-processing.html#sec-abstract-operations-for-regexp-creation" title="Abstract Operations for RegExp Creation">22.2.3 Abstract Operations for RegExp Creation</a><ol class="toc"><li><a href="text-processing.html#sec-regexpcreate" title="RegExpCreate ( P, F )">22.2.3.1 RegExpCreate ( <var>P</var>, <var>F</var> )</a></li><li><a href="text-processing.html#sec-regexpalloc" title="RegExpAlloc ( newTarget )">22.2.3.2 RegExpAlloc ( <var>newTarget</var> )</a></li><li><a href="text-processing.html#sec-regexpinitialize" title="RegExpInitialize ( obj, pattern, flags )">22.2.3.3 RegExpInitialize ( <var>obj</var>, <var>pattern</var>, <var>flags</var> )</a></li><li><a href="text-processing.html#sec-parsepattern" title="Static Semantics: ParsePattern ( patternText, u, v )">22.2.3.4 SS: ParsePattern ( <var>patternText</var>, <var>u</var>, <var>v</var> )</a></li></ol></li><li>+<a href="text-processing.html#sec-regexp-constructor" title="The RegExp Constructor">22.2.4 The RegExp Constructor</a><ol class="toc"><li><a href="text-processing.html#sec-regexp-pattern-flags" title="RegExp ( pattern, flags )">22.2.4.1 RegExp ( <var>pattern</var>, <var>flags</var> )</a></li></ol></li><li>+<a href="text-processing.html#sec-properties-of-the-regexp-constructor" title="Properties of the RegExp Constructor">22.2.5 Properties of the RegExp Constructor</a><ol class="toc"><li><a href="text-processing.html#sec-regexp.prototype" title="RegExp.prototype">22.2.5.1 RegExp.prototype</a></li><li><a href="text-processing.html#sec-get-regexp-%symbol.species%" title="get RegExp [ %Symbol.species% ]">22.2.5.2 get RegExp [ %Symbol.species% ]</a></li></ol></li><li>+<a href="text-processing.html#sec-properties-of-the-regexp-prototype-object" title="Properties of the RegExp Prototype Object">22.2.6 Properties of the RegExp Prototype Object</a><ol class="toc"><li><a href="text-processing.html#sec-regexp.prototype.constructor" title="RegExp.prototype.constructor">22.2.6.1 RegExp.prototype.constructor</a></li><li><a href="text-processing.html#sec-regexp.prototype.exec" title="RegExp.prototype.exec ( string )">22.2.6.2 RegExp.prototype.exec ( <var>string</var> )</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.dotAll" title="get RegExp.prototype.dotAll">22.2.6.3 get RegExp.prototype.dotAll</a></li><li>+<a href="text-processing.html#sec-get-regexp.prototype.flags" title="get RegExp.prototype.flags">22.2.6.4 get RegExp.prototype.flags</a><ol class="toc"><li><a href="text-processing.html#sec-regexphasflag" title="RegExpHasFlag ( R, codeUnit )">22.2.6.4.1 RegExpHasFlag ( <var>R</var>, <var>codeUnit</var> )</a></li></ol></li><li><a href="text-processing.html#sec-get-regexp.prototype.global" title="get RegExp.prototype.global">22.2.6.5 get RegExp.prototype.global</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.hasIndices" title="get RegExp.prototype.hasIndices">22.2.6.6 get RegExp.prototype.hasIndices</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.ignorecase" title="get RegExp.prototype.ignoreCase">22.2.6.7 get RegExp.prototype.ignoreCase</a></li><li><a href="text-processing.html#sec-regexp.prototype-%symbol.match%" title="RegExp.prototype [ %Symbol.match% ] ( string )">22.2.6.8 RegExp.prototype [ %Symbol.match% ] ( <var>string</var> )</a></li><li><a href="text-processing.html#sec-regexp-prototype-%symbol.matchall%" title="RegExp.prototype [ %Symbol.matchAll% ] ( string )">22.2.6.9 RegExp.prototype [ %Symbol.matchAll% ] ( <var>string</var> )</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.multiline" title="get RegExp.prototype.multiline">22.2.6.10 get RegExp.prototype.multiline</a></li><li><a href="text-processing.html#sec-regexp.prototype-%symbol.replace%" title="RegExp.prototype [ %Symbol.replace% ] ( string, replaceValue )">22.2.6.11 RegExp.prototype [ %Symbol.replace% ] ( <var>string</var>, <var>replaceValue</var> )</a></li><li><a href="text-processing.html#sec-regexp.prototype-%symbol.search%" title="RegExp.prototype [ %Symbol.search% ] ( string )">22.2.6.12 RegExp.prototype [ %Symbol.search% ] ( <var>string</var> )</a></li><li>+<a href="text-processing.html#sec-get-regexp.prototype.source" title="get RegExp.prototype.source">22.2.6.13 get RegExp.prototype.source</a><ol class="toc"><li><a href="text-processing.html#sec-escaperegexppattern" title="EscapeRegExpPattern ( P, F )">22.2.6.13.1 EscapeRegExpPattern ( <var>P</var>, <var>F</var> )</a></li></ol></li><li><a href="text-processing.html#sec-regexp.prototype-%symbol.split%" title="RegExp.prototype [ %Symbol.split% ] ( string, limit )">22.2.6.14 RegExp.prototype [ %Symbol.split% ] ( <var>string</var>, <var>limit</var> )</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.sticky" title="get RegExp.prototype.sticky">22.2.6.15 get RegExp.prototype.sticky</a></li><li><a href="text-processing.html#sec-regexp.prototype.test" title="RegExp.prototype.test ( S )">22.2.6.16 RegExp.prototype.test ( <var>S</var> )</a></li><li><a href="text-processing.html#sec-regexp.prototype.tostring" title="RegExp.prototype.toString ( )">22.2.6.17 RegExp.prototype.toString ( )</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.unicode" title="get RegExp.prototype.unicode">22.2.6.18 get RegExp.prototype.unicode</a></li><li><a href="text-processing.html#sec-get-regexp.prototype.unicodesets" title="get RegExp.prototype.unicodeSets">22.2.6.19 get RegExp.prototype.unicodeSets</a></li></ol></li><li>+<a href="text-processing.html#sec-abstract-operations-for-regexp-matching" title="Abstract Operations for RegExp Matching">22.2.7 Abstract Operations for RegExp Matching</a><ol class="toc"><li><a href="text-processing.html#sec-regexpexec" title="RegExpExec ( R, S )">22.2.7.1 RegExpExec ( <var>R</var>, <var>S</var> )</a></li><li><a href="text-processing.html#sec-regexpbuiltinexec" title="RegExpBuiltinExec ( R, S )">22.2.7.2 RegExpBuiltinExec ( <var>R</var>, <var>S</var> )</a></li><li><a href="text-processing.html#sec-advancestringindex" title="AdvanceStringIndex ( S, index, unicode )">22.2.7.3 AdvanceStringIndex ( <var>S</var>, <var>index</var>, <var>unicode</var> )</a></li><li><a href="text-processing.html#sec-getstringindex" title="GetStringIndex ( S, codePointIndex )">22.2.7.4 GetStringIndex ( <var>S</var>, <var>codePointIndex</var> )</a></li><li><a href="text-processing.html#sec-match-records" title="Match Records">22.2.7.5 Match Records</a></li><li><a href="text-processing.html#sec-getmatchstring" title="GetMatchString ( S, match )">22.2.7.6 GetMatchString ( <var>S</var>, <var>match</var> )</a></li><li><a href="text-processing.html#sec-getmatchindexpair" title="GetMatchIndexPair ( S, match )">22.2.7.7 GetMatchIndexPair ( <var>S</var>, <var>match</var> )</a></li><li><a href="text-processing.html#sec-makematchindicesindexpairarray" title="MakeMatchIndicesIndexPairArray ( S, indices, groupNames, hasGroups )">22.2.7.8 MakeMatchIndicesIndexPairArray ( <var>S</var>, <var>indices</var>, <var>groupNames</var>, <var>hasGroups</var> )</a></li></ol></li><li>+<a href="text-processing.html#sec-properties-of-regexp-instances" title="Properties of RegExp Instances">22.2.8 Properties of RegExp Instances</a><ol class="toc"><li><a href="text-processing.html#sec-lastindex" title="lastIndex">22.2.8.1 lastIndex</a></li></ol></li><li>+<a href="text-processing.html#sec-regexp-string-iterator-objects" title="RegExp String Iterator Objects">22.2.9 RegExp String Iterator Objects</a><ol class="toc"><li><a href="text-processing.html#sec-createregexpstringiterator" title="CreateRegExpStringIterator ( R, S, global, fullUnicode )">22.2.9.1 CreateRegExpStringIterator ( <var>R</var>, <var>S</var>, <var>global</var>, <var>fullUnicode</var> )</a></li><li>+<a href="text-processing.html#sec-%regexpstringiteratorprototype%-object" title="The %RegExpStringIteratorPrototype% Object">22.2.9.2 The %RegExpStringIteratorPrototype% Object</a><ol class="toc"><li><a href="text-processing.html#sec-%regexpstringiteratorprototype%.next" title="%RegExpStringIteratorPrototype%.next ( )">22.2.9.2.1 %RegExpStringIteratorPrototype%.next ( )</a></li><li><a href="text-processing.html#sec-%regexpstringiteratorprototype%-%symbol.tostringtag%" title="%RegExpStringIteratorPrototype% [ %Symbol.toStringTag% ]">22.2.9.2.2 %RegExpStringIteratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li></ol></li></ol></li><li>+<a href="indexed-collections.html#sec-indexed-collections" title="Indexed Collections">23 Indexed Collections</a><ol class="toc"><li>+<a href="indexed-collections.html#sec-array-objects" title="Array Objects">23.1 Array Objects</a><ol class="toc"><li>+<a href="indexed-collections.html#sec-array-constructor" title="The Array Constructor">23.1.1 The Array Constructor</a><ol class="toc"><li><a href="indexed-collections.html#sec-array" title="Array ( ...values )">23.1.1.1 Array ( ...<var>values</var> )</a></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-the-array-constructor" title="Properties of the Array Constructor">23.1.2 Properties of the Array Constructor</a><ol class="toc"><li><a href="indexed-collections.html#sec-array.from" title="Array.from ( items [ , mapper [ , thisArg ] ] )">23.1.2.1 Array.from ( <var>items</var> [ , <var>mapper</var> [ , <var>thisArg</var> ] ] )</a></li><li><a href="indexed-collections.html#sec-array.isarray" title="Array.isArray ( arg )">23.1.2.2 Array.isArray ( <var>arg</var> )</a></li><li><a href="indexed-collections.html#sec-array.of" title="Array.of ( ...items )">23.1.2.3 Array.of ( ...<var>items</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype" title="Array.prototype">23.1.2.4 Array.prototype</a></li><li><a href="indexed-collections.html#sec-get-array-%symbol.species%" title="get Array [ %Symbol.species% ]">23.1.2.5 get Array [ %Symbol.species% ]</a></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-the-array-prototype-object" title="Properties of the Array Prototype Object">23.1.3 Properties of the Array Prototype Object</a><ol class="toc"><li><a href="indexed-collections.html#sec-array.prototype.at" title="Array.prototype.at ( index )">23.1.3.1 Array.prototype.at ( <var>index</var> )</a></li><li>+<a href="indexed-collections.html#sec-array.prototype.concat" title="Array.prototype.concat ( ...items )">23.1.3.2 Array.prototype.concat ( ...<var>items</var> )</a><ol class="toc"><li><a href="indexed-collections.html#sec-isconcatspreadable" title="IsConcatSpreadable ( O )">23.1.3.2.1 IsConcatSpreadable ( <var>O</var> )</a></li></ol></li><li><a href="indexed-collections.html#sec-array.prototype.constructor" title="Array.prototype.constructor">23.1.3.3 Array.prototype.constructor</a></li><li><a href="indexed-collections.html#sec-array.prototype.copywithin" title="Array.prototype.copyWithin ( target, start [ , end ] )">23.1.3.4 Array.prototype.copyWithin ( <var>target</var>, <var>start</var> [ , <var>end</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.entries" title="Array.prototype.entries ( )">23.1.3.5 Array.prototype.entries ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.every" title="Array.prototype.every ( callback [ , thisArg ] )">23.1.3.6 Array.prototype.every ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.fill" title="Array.prototype.fill ( value [ , start [ , end ] ] )">23.1.3.7 Array.prototype.fill ( <var>value</var> [ , <var>start</var> [ , <var>end</var> ] ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.filter" title="Array.prototype.filter ( callback [ , thisArg ] )">23.1.3.8 Array.prototype.filter ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.find" title="Array.prototype.find ( predicate [ , thisArg ] )">23.1.3.9 Array.prototype.find ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.findindex" title="Array.prototype.findIndex ( predicate [ , thisArg ] )">23.1.3.10 Array.prototype.findIndex ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.findlast" title="Array.prototype.findLast ( predicate [ , thisArg ] )">23.1.3.11 Array.prototype.findLast ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li>+<a href="indexed-collections.html#sec-array.prototype.findlastindex" title="Array.prototype.findLastIndex ( predicate [ , thisArg ] )">23.1.3.12 Array.prototype.findLastIndex ( <var>predicate</var> [ , <var>thisArg</var> ] )</a><ol class="toc"><li><a href="indexed-collections.html#sec-findviapredicate" title="FindViaPredicate ( O, len, direction, predicate, thisArg )">23.1.3.12.1 FindViaPredicate ( <var>O</var>, <var>len</var>, <var>direction</var>, <var>predicate</var>, <var>thisArg</var> )</a></li></ol></li><li>+<a href="indexed-collections.html#sec-array.prototype.flat" title="Array.prototype.flat ( [ depth ] )">23.1.3.13 Array.prototype.flat ( [ <var>depth</var> ] )</a><ol class="toc"><li><a href="indexed-collections.html#sec-flattenintoarray" title="FlattenIntoArray ( target, source, sourceLen, start, depth [ , mapperFunction [ , thisArg ] ] )">23.1.3.13.1 FlattenIntoArray ( <var>target</var>, <var>source</var>, <var>sourceLen</var>, <var>start</var>, <var>depth</var> [ , <var>mapperFunction</var> [ , <var>thisArg</var> ] ] )</a></li></ol></li><li><a href="indexed-collections.html#sec-array.prototype.flatmap" title="Array.prototype.flatMap ( mapperFunction [ , thisArg ] )">23.1.3.14 Array.prototype.flatMap ( <var>mapperFunction</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.foreach" title="Array.prototype.forEach ( callback [ , thisArg ] )">23.1.3.15 Array.prototype.forEach ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.includes" title="Array.prototype.includes ( searchElement [ , fromIndex ] )">23.1.3.16 Array.prototype.includes ( <var>searchElement</var> [ , <var>fromIndex</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.indexof" title="Array.prototype.indexOf ( searchElement [ , fromIndex ] )">23.1.3.17 Array.prototype.indexOf ( <var>searchElement</var> [ , <var>fromIndex</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.join" title="Array.prototype.join ( separator )">23.1.3.18 Array.prototype.join ( <var>separator</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.keys" title="Array.prototype.keys ( )">23.1.3.19 Array.prototype.keys ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.lastindexof" title="Array.prototype.lastIndexOf ( searchElement [ , fromIndex ] )">23.1.3.20 Array.prototype.lastIndexOf ( <var>searchElement</var> [ , <var>fromIndex</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.map" title="Array.prototype.map ( callback [ , thisArg ] )">23.1.3.21 Array.prototype.map ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.pop" title="Array.prototype.pop ( )">23.1.3.22 Array.prototype.pop ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.push" title="Array.prototype.push ( ...items )">23.1.3.23 Array.prototype.push ( ...<var>items</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.reduce" title="Array.prototype.reduce ( callback [ , initialValue ] )">23.1.3.24 Array.prototype.reduce ( <var>callback</var> [ , <var>initialValue</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.reduceright" title="Array.prototype.reduceRight ( callback [ , initialValue ] )">23.1.3.25 Array.prototype.reduceRight ( <var>callback</var> [ , <var>initialValue</var> ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.reverse" title="Array.prototype.reverse ( )">23.1.3.26 Array.prototype.reverse ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.shift" title="Array.prototype.shift ( )">23.1.3.27 Array.prototype.shift ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.slice" title="Array.prototype.slice ( start, end )">23.1.3.28 Array.prototype.slice ( <var>start</var>, <var>end</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.some" title="Array.prototype.some ( callback [ , thisArg ] )">23.1.3.29 Array.prototype.some ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li>+<a href="indexed-collections.html#sec-array.prototype.sort" title="Array.prototype.sort ( comparator )">23.1.3.30 Array.prototype.sort ( <var>comparator</var> )</a><ol class="toc"><li><a href="indexed-collections.html#sec-sortindexedproperties" title="SortIndexedProperties ( obj, len, SortCompare, holes )">23.1.3.30.1 SortIndexedProperties ( <var>obj</var>, <var>len</var>, <var>SortCompare</var>, <var>holes</var> )</a></li><li><a href="indexed-collections.html#sec-comparearrayelements" title="CompareArrayElements ( x, y, comparator )">23.1.3.30.2 CompareArrayElements ( <var>x</var>, <var>y</var>, <var>comparator</var> )</a></li></ol></li><li><a href="indexed-collections.html#sec-array.prototype.splice" title="Array.prototype.splice ( start, deleteCount, ...items )">23.1.3.31 Array.prototype.splice ( <var>start</var>, <var>deleteCount</var>, ...<var>items</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.tolocalestring" title="Array.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] )">23.1.3.32 Array.prototype.toLocaleString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="indexed-collections.html#sec-array.prototype.toreversed" title="Array.prototype.toReversed ( )">23.1.3.33 Array.prototype.toReversed ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.tosorted" title="Array.prototype.toSorted ( comparator )">23.1.3.34 Array.prototype.toSorted ( <var>comparator</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.tospliced" title="Array.prototype.toSpliced ( start, skipCount, ...items )">23.1.3.35 Array.prototype.toSpliced ( <var>start</var>, <var>skipCount</var>, ...<var>items</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.tostring" title="Array.prototype.toString ( )">23.1.3.36 Array.prototype.toString ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.unshift" title="Array.prototype.unshift ( ...items )">23.1.3.37 Array.prototype.unshift ( ...<var>items</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype.values" title="Array.prototype.values ( )">23.1.3.38 Array.prototype.values ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype.with" title="Array.prototype.with ( index, value )">23.1.3.39 Array.prototype.with ( <var>index</var>, <var>value</var> )</a></li><li><a href="indexed-collections.html#sec-array.prototype-%symbol.iterator%" title="Array.prototype [ %Symbol.iterator% ] ( )">23.1.3.40 Array.prototype [ %Symbol.iterator% ] ( )</a></li><li><a href="indexed-collections.html#sec-array.prototype-%symbol.unscopables%" title="Array.prototype [ %Symbol.unscopables% ]">23.1.3.41 Array.prototype [ %Symbol.unscopables% ]</a></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-array-instances" title="Properties of Array Instances">23.1.4 Properties of Array Instances</a><ol class="toc"><li><a href="indexed-collections.html#sec-properties-of-array-instances-length" title="length">23.1.4.1 length</a></li></ol></li><li>+<a href="indexed-collections.html#sec-array-iterator-objects" title="Array Iterator Objects">23.1.5 Array Iterator Objects</a><ol class="toc"><li><a href="indexed-collections.html#sec-createarrayiterator" title="CreateArrayIterator ( array, kind )">23.1.5.1 CreateArrayIterator ( <var>array</var>, <var>kind</var> )</a></li><li>+<a href="indexed-collections.html#sec-%arrayiteratorprototype%-object" title="The %ArrayIteratorPrototype% Object">23.1.5.2 The %ArrayIteratorPrototype% Object</a><ol class="toc"><li><a href="indexed-collections.html#sec-%arrayiteratorprototype%.next" title="%ArrayIteratorPrototype%.next ( )">23.1.5.2.1 %ArrayIteratorPrototype%.next ( )</a></li><li><a href="indexed-collections.html#sec-%arrayiteratorprototype%-%symbol.tostringtag%" title="%ArrayIteratorPrototype% [ %Symbol.toStringTag% ]">23.1.5.2.2 %ArrayIteratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li></ol></li><li>+<a href="indexed-collections.html#sec-typedarray-objects" title="TypedArray Objects">23.2 TypedArray Objects</a><ol class="toc"><li>+<a href="indexed-collections.html#sec-%typedarray%-intrinsic-object" title="The %TypedArray% Intrinsic Object">23.2.1 The %TypedArray% Intrinsic Object</a><ol class="toc"><li><a href="indexed-collections.html#sec-%typedarray%" title="%TypedArray% ( )">23.2.1.1 %TypedArray% ( )</a></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-the-%typedarray%-intrinsic-object" title="Properties of the %TypedArray% Intrinsic Object">23.2.2 Properties of the %TypedArray% Intrinsic Object</a><ol class="toc"><li><a href="indexed-collections.html#sec-%typedarray%.from" title="%TypedArray%.from ( source [ , mapper [ , thisArg ] ] )">23.2.2.1 %TypedArray%.from ( <var>source</var> [ , <var>mapper</var> [ , <var>thisArg</var> ] ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.of" title="%TypedArray%.of ( ...items )">23.2.2.2 %TypedArray%.of ( ...<var>items</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype" title="%TypedArray%.prototype">23.2.2.3 %TypedArray%.prototype</a></li><li><a href="indexed-collections.html#sec-get-%typedarray%-%symbol.species%" title="get %TypedArray% [ %Symbol.species% ]">23.2.2.4 get %TypedArray% [ %Symbol.species% ]</a></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-the-%typedarrayprototype%-object" title="Properties of the %TypedArray% Prototype Object">23.2.3 Properties of the %TypedArray% Prototype Object</a><ol class="toc"><li><a href="indexed-collections.html#sec-%typedarray%.prototype.at" title="%TypedArray%.prototype.at ( index )">23.2.3.1 %TypedArray%.prototype.at ( <var>index</var> )</a></li><li><a href="indexed-collections.html#sec-get-%typedarray%.prototype.buffer" title="get %TypedArray%.prototype.buffer">23.2.3.2 get %TypedArray%.prototype.buffer</a></li><li><a href="indexed-collections.html#sec-get-%typedarray%.prototype.bytelength" title="get %TypedArray%.prototype.byteLength">23.2.3.3 get %TypedArray%.prototype.byteLength</a></li><li><a href="indexed-collections.html#sec-get-%typedarray%.prototype.byteoffset" title="get %TypedArray%.prototype.byteOffset">23.2.3.4 get %TypedArray%.prototype.byteOffset</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.constructor" title="%TypedArray%.prototype.constructor">23.2.3.5 %TypedArray%.prototype.constructor</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.copywithin" title="%TypedArray%.prototype.copyWithin ( target, start [ , end ] )">23.2.3.6 %TypedArray%.prototype.copyWithin ( <var>target</var>, <var>start</var> [ , <var>end</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.entries" title="%TypedArray%.prototype.entries ( )">23.2.3.7 %TypedArray%.prototype.entries ( )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.every" title="%TypedArray%.prototype.every ( callback [ , thisArg ] )">23.2.3.8 %TypedArray%.prototype.every ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.fill" title="%TypedArray%.prototype.fill ( value [ , start [ , end ] ] )">23.2.3.9 %TypedArray%.prototype.fill ( <var>value</var> [ , <var>start</var> [ , <var>end</var> ] ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.filter" title="%TypedArray%.prototype.filter ( callback [ , thisArg ] )">23.2.3.10 %TypedArray%.prototype.filter ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.find" title="%TypedArray%.prototype.find ( predicate [ , thisArg ] )">23.2.3.11 %TypedArray%.prototype.find ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.findindex" title="%TypedArray%.prototype.findIndex ( predicate [ , thisArg ] )">23.2.3.12 %TypedArray%.prototype.findIndex ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.findlast" title="%TypedArray%.prototype.findLast ( predicate [ , thisArg ] )">23.2.3.13 %TypedArray%.prototype.findLast ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.findlastindex" title="%TypedArray%.prototype.findLastIndex ( predicate [ , thisArg ] )">23.2.3.14 %TypedArray%.prototype.findLastIndex ( <var>predicate</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.foreach" title="%TypedArray%.prototype.forEach ( callback [ , thisArg ] )">23.2.3.15 %TypedArray%.prototype.forEach ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.includes" title="%TypedArray%.prototype.includes ( searchElement [ , fromIndex ] )">23.2.3.16 %TypedArray%.prototype.includes ( <var>searchElement</var> [ , <var>fromIndex</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.indexof" title="%TypedArray%.prototype.indexOf ( searchElement [ , fromIndex ] )">23.2.3.17 %TypedArray%.prototype.indexOf ( <var>searchElement</var> [ , <var>fromIndex</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.join" title="%TypedArray%.prototype.join ( separator )">23.2.3.18 %TypedArray%.prototype.join ( <var>separator</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.keys" title="%TypedArray%.prototype.keys ( )">23.2.3.19 %TypedArray%.prototype.keys ( )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.lastindexof" title="%TypedArray%.prototype.lastIndexOf ( searchElement [ , fromIndex ] )">23.2.3.20 %TypedArray%.prototype.lastIndexOf ( <var>searchElement</var> [ , <var>fromIndex</var> ] )</a></li><li><a href="indexed-collections.html#sec-get-%typedarray%.prototype.length" title="get %TypedArray%.prototype.length">23.2.3.21 get %TypedArray%.prototype.length</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.map" title="%TypedArray%.prototype.map ( callback [ , thisArg ] )">23.2.3.22 %TypedArray%.prototype.map ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.reduce" title="%TypedArray%.prototype.reduce ( callback [ , initialValue ] )">23.2.3.23 %TypedArray%.prototype.reduce ( <var>callback</var> [ , <var>initialValue</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.reduceright" title="%TypedArray%.prototype.reduceRight ( callback [ , initialValue ] )">23.2.3.24 %TypedArray%.prototype.reduceRight ( <var>callback</var> [ , <var>initialValue</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.reverse" title="%TypedArray%.prototype.reverse ( )">23.2.3.25 %TypedArray%.prototype.reverse ( )</a></li><li>+<a href="indexed-collections.html#sec-%typedarray%.prototype.set" title="%TypedArray%.prototype.set ( source [ , offset ] )">23.2.3.26 %TypedArray%.prototype.set ( <var>source</var> [ , <var>offset</var> ] )</a><ol class="toc"><li><a href="indexed-collections.html#sec-settypedarrayfromtypedarray" title="SetTypedArrayFromTypedArray ( target, targetOffset, source )">23.2.3.26.1 SetTypedArrayFromTypedArray ( <var>target</var>, <var>targetOffset</var>, <var>source</var> )</a></li><li><a href="indexed-collections.html#sec-settypedarrayfromarraylike" title="SetTypedArrayFromArrayLike ( target, targetOffset, source )">23.2.3.26.2 SetTypedArrayFromArrayLike ( <var>target</var>, <var>targetOffset</var>, <var>source</var> )</a></li></ol></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.slice" title="%TypedArray%.prototype.slice ( start, end )">23.2.3.27 %TypedArray%.prototype.slice ( <var>start</var>, <var>end</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.some" title="%TypedArray%.prototype.some ( callback [ , thisArg ] )">23.2.3.28 %TypedArray%.prototype.some ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.sort" title="%TypedArray%.prototype.sort ( comparator )">23.2.3.29 %TypedArray%.prototype.sort ( <var>comparator</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.subarray" title="%TypedArray%.prototype.subarray ( start, end )">23.2.3.30 %TypedArray%.prototype.subarray ( <var>start</var>, <var>end</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.tolocalestring" title="%TypedArray%.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] )">23.2.3.31 %TypedArray%.prototype.toLocaleString ( [ <var>reserved1</var> [ , <var>reserved2</var> ] ] )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.toreversed" title="%TypedArray%.prototype.toReversed ( )">23.2.3.32 %TypedArray%.prototype.toReversed ( )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.tosorted" title="%TypedArray%.prototype.toSorted ( comparator )">23.2.3.33 %TypedArray%.prototype.toSorted ( <var>comparator</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.tostring" title="%TypedArray%.prototype.toString ( )">23.2.3.34 %TypedArray%.prototype.toString ( )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.values" title="%TypedArray%.prototype.values ( )">23.2.3.35 %TypedArray%.prototype.values ( )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype.with" title="%TypedArray%.prototype.with ( index, value )">23.2.3.36 %TypedArray%.prototype.with ( <var>index</var>, <var>value</var> )</a></li><li><a href="indexed-collections.html#sec-%typedarray%.prototype-%symbol.iterator%" title="%TypedArray%.prototype [ %Symbol.iterator% ] ( )">23.2.3.37 %TypedArray%.prototype [ %Symbol.iterator% ] ( )</a></li><li><a href="indexed-collections.html#sec-get-%typedarray%.prototype-%symbol.tostringtag%" title="get %TypedArray%.prototype [ %Symbol.toStringTag% ]">23.2.3.38 get %TypedArray%.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="indexed-collections.html#sec-abstract-operations-for-typedarray-objects" title="Abstract Operations for TypedArray Objects">23.2.4 Abstract Operations for TypedArray Objects</a><ol class="toc"><li><a href="indexed-collections.html#typedarray-species-create" title="TypedArraySpeciesCreate ( exemplar, argumentList )">23.2.4.1 TypedArraySpeciesCreate ( <var>exemplar</var>, <var>argumentList</var> )</a></li><li><a href="indexed-collections.html#sec-typedarraycreatefromconstructor" title="TypedArrayCreateFromConstructor ( constructor, argumentList )">23.2.4.2 TypedArrayCreateFromConstructor ( <var>constructor</var>, <var>argumentList</var> )</a></li><li><a href="indexed-collections.html#sec-typedarray-create-same-type" title="TypedArrayCreateSameType ( exemplar, argumentList )">23.2.4.3 TypedArrayCreateSameType ( <var>exemplar</var>, <var>argumentList</var> )</a></li><li><a href="indexed-collections.html#sec-validatetypedarray" title="ValidateTypedArray ( O, order )">23.2.4.4 ValidateTypedArray ( <var>O</var>, <var>order</var> )</a></li><li><a href="indexed-collections.html#sec-typedarrayelementsize" title="TypedArrayElementSize ( O )">23.2.4.5 TypedArrayElementSize ( <var>O</var> )</a></li><li><a href="indexed-collections.html#sec-typedarrayelementtype" title="TypedArrayElementType ( O )">23.2.4.6 TypedArrayElementType ( <var>O</var> )</a></li><li><a href="indexed-collections.html#sec-comparetypedarrayelements" title="CompareTypedArrayElements ( x, y, comparator )">23.2.4.7 CompareTypedArrayElements ( <var>x</var>, <var>y</var>, <var>comparator</var> )</a></li></ol></li><li>+<a href="indexed-collections.html#sec-typedarray-constructors" title="The TypedArray Constructors">23.2.5 The <var>TypedArray</var> Constructors</a><ol class="toc"><li>+<a href="indexed-collections.html#sec-typedarray" title="TypedArray ( ...args )">23.2.5.1 <var>TypedArray</var> ( ...<var>args</var> )</a><ol class="toc"><li><a href="indexed-collections.html#sec-allocatetypedarray" title="AllocateTypedArray ( constructorName, newTarget, defaultProto [ , length ] )">23.2.5.1.1 AllocateTypedArray ( <var>constructorName</var>, <var>newTarget</var>, <var>defaultProto</var> [ , <var>length</var> ] )</a></li><li><a href="indexed-collections.html#sec-initializetypedarrayfromtypedarray" title="InitializeTypedArrayFromTypedArray ( O, srcArray )">23.2.5.1.2 InitializeTypedArrayFromTypedArray ( <var>O</var>, <var>srcArray</var> )</a></li><li><a href="indexed-collections.html#sec-initializetypedarrayfromarraybuffer" title="InitializeTypedArrayFromArrayBuffer ( O, buffer, byteOffset, length )">23.2.5.1.3 InitializeTypedArrayFromArrayBuffer ( <var>O</var>, <var>buffer</var>, <var>byteOffset</var>, <var>length</var> )</a></li><li><a href="indexed-collections.html#sec-initializetypedarrayfromlist" title="InitializeTypedArrayFromList ( O, values )">23.2.5.1.4 InitializeTypedArrayFromList ( <var>O</var>, <var>values</var> )</a></li><li><a href="indexed-collections.html#sec-initializetypedarrayfromarraylike" title="InitializeTypedArrayFromArrayLike ( O, arrayLike )">23.2.5.1.5 InitializeTypedArrayFromArrayLike ( <var>O</var>, <var>arrayLike</var> )</a></li><li><a href="indexed-collections.html#sec-allocatetypedarraybuffer" title="AllocateTypedArrayBuffer ( O, length )">23.2.5.1.6 AllocateTypedArrayBuffer ( <var>O</var>, <var>length</var> )</a></li></ol></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-the-typedarray-constructors" title="Properties of the TypedArray Constructors">23.2.6 Properties of the <var>TypedArray</var> Constructors</a><ol class="toc"><li><a href="indexed-collections.html#sec-typedarray.bytes_per_element" title="TypedArray.BYTES_PER_ELEMENT">23.2.6.1 <var>TypedArray</var>.BYTES_PER_ELEMENT</a></li><li><a href="indexed-collections.html#sec-typedarray.prototype" title="TypedArray.prototype">23.2.6.2 <var>TypedArray</var>.prototype</a></li></ol></li><li>+<a href="indexed-collections.html#sec-properties-of-typedarray-prototype-objects" title="Properties of the TypedArray Prototype Objects">23.2.7 Properties of the <var>TypedArray</var> Prototype Objects</a><ol class="toc"><li><a href="indexed-collections.html#sec-typedarray.prototype.bytes_per_element" title="TypedArray.prototype.BYTES_PER_ELEMENT">23.2.7.1 <var>TypedArray</var>.prototype.BYTES_PER_ELEMENT</a></li><li><a href="indexed-collections.html#sec-typedarray.prototype.constructor" title="TypedArray.prototype.constructor">23.2.7.2 <var>TypedArray</var>.prototype.constructor</a></li></ol></li><li><a href="indexed-collections.html#sec-properties-of-typedarray-instances" title="Properties of TypedArray Instances">23.2.8 Properties of <var>TypedArray</var> Instances</a></li></ol></li></ol></li><li>+<a href="keyed-collections.html#sec-keyed-collections" title="Keyed Collections">24 Keyed Collections</a><ol class="toc"><li>+<a href="keyed-collections.html#sec-map-objects" title="Map Objects">24.1 Map Objects</a><ol class="toc"><li>+<a href="keyed-collections.html#sec-map-constructor" title="The Map Constructor">24.1.1 The Map Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-map-iterable" title="Map ( [ iterable ] )">24.1.1.1 Map ( [ <var>iterable</var> ] )</a></li><li><a href="keyed-collections.html#sec-add-entries-from-iterable" title="AddEntriesFromIterable ( target, iterable, adder )">24.1.1.2 AddEntriesFromIterable ( <var>target</var>, <var>iterable</var>, <var>adder</var> )</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-map-constructor" title="Properties of the Map Constructor">24.1.2 Properties of the Map Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-map.groupby" title="Map.groupBy ( items, callback )">24.1.2.1 Map.groupBy ( <var>items</var>, <var>callback</var> )</a></li><li><a href="keyed-collections.html#sec-map.prototype" title="Map.prototype">24.1.2.2 Map.prototype</a></li><li><a href="keyed-collections.html#sec-get-map-%symbol.species%" title="get Map [ %Symbol.species% ]">24.1.2.3 get Map [ %Symbol.species% ]</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-map-prototype-object" title="Properties of the Map Prototype Object">24.1.3 Properties of the Map Prototype Object</a><ol class="toc"><li><a href="keyed-collections.html#sec-map.prototype.clear" title="Map.prototype.clear ( )">24.1.3.1 Map.prototype.clear ( )</a></li><li><a href="keyed-collections.html#sec-map.prototype.constructor" title="Map.prototype.constructor">24.1.3.2 Map.prototype.constructor</a></li><li><a href="keyed-collections.html#sec-map.prototype.delete" title="Map.prototype.delete ( key )">24.1.3.3 Map.prototype.delete ( <var>key</var> )</a></li><li><a href="keyed-collections.html#sec-map.prototype.entries" title="Map.prototype.entries ( )">24.1.3.4 Map.prototype.entries ( )</a></li><li><a href="keyed-collections.html#sec-map.prototype.foreach" title="Map.prototype.forEach ( callback [ , thisArg ] )">24.1.3.5 Map.prototype.forEach ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="keyed-collections.html#sec-map.prototype.get" title="Map.prototype.get ( key )">24.1.3.6 Map.prototype.get ( <var>key</var> )</a></li><li><a href="keyed-collections.html#sec-map.prototype.has" title="Map.prototype.has ( key )">24.1.3.7 Map.prototype.has ( <var>key</var> )</a></li><li><a href="keyed-collections.html#sec-map.prototype.keys" title="Map.prototype.keys ( )">24.1.3.8 Map.prototype.keys ( )</a></li><li><a href="keyed-collections.html#sec-map.prototype.set" title="Map.prototype.set ( key, value )">24.1.3.9 Map.prototype.set ( <var>key</var>, <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-get-map.prototype.size" title="get Map.prototype.size">24.1.3.10 get Map.prototype.size</a></li><li><a href="keyed-collections.html#sec-map.prototype.values" title="Map.prototype.values ( )">24.1.3.11 Map.prototype.values ( )</a></li><li><a href="keyed-collections.html#sec-map.prototype-%symbol.iterator%" title="Map.prototype [ %Symbol.iterator% ] ( )">24.1.3.12 Map.prototype [ %Symbol.iterator% ] ( )</a></li><li><a href="keyed-collections.html#sec-map.prototype-%symbol.tostringtag%" title="Map.prototype [ %Symbol.toStringTag% ]">24.1.3.13 Map.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="keyed-collections.html#sec-properties-of-map-instances" title="Properties of Map Instances">24.1.4 Properties of Map Instances</a></li><li>+<a href="keyed-collections.html#sec-map-iterator-objects" title="Map Iterator Objects">24.1.5 Map Iterator Objects</a><ol class="toc"><li><a href="keyed-collections.html#sec-createmapiterator" title="CreateMapIterator ( map, kind )">24.1.5.1 CreateMapIterator ( <var>map</var>, <var>kind</var> )</a></li><li>+<a href="keyed-collections.html#sec-%mapiteratorprototype%-object" title="The %MapIteratorPrototype% Object">24.1.5.2 The %MapIteratorPrototype% Object</a><ol class="toc"><li><a href="keyed-collections.html#sec-%mapiteratorprototype%.next" title="%MapIteratorPrototype%.next ( )">24.1.5.2.1 %MapIteratorPrototype%.next ( )</a></li><li><a href="keyed-collections.html#sec-%mapiteratorprototype%-%symbol.tostringtag%" title="%MapIteratorPrototype% [ %Symbol.toStringTag% ]">24.1.5.2.2 %MapIteratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li></ol></li><li>+<a href="keyed-collections.html#sec-set-objects" title="Set Objects">24.2 Set Objects</a><ol class="toc"><li>+<a href="keyed-collections.html#sec-abstract-operations-for-set-objects" title="Abstract Operations For Set Objects">24.2.1 Abstract Operations For Set Objects</a><ol class="toc"><li><a href="keyed-collections.html#sec-set-records" title="Set Records">24.2.1.1 Set Records</a></li><li><a href="keyed-collections.html#sec-getsetrecord" title="GetSetRecord ( obj )">24.2.1.2 GetSetRecord ( <var>obj</var> )</a></li><li><a href="keyed-collections.html#sec-setdatahas" title="SetDataHas ( setData, value )">24.2.1.3 SetDataHas ( <var>setData</var>, <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-setdataindex" title="SetDataIndex ( setData, value )">24.2.1.4 SetDataIndex ( <var>setData</var>, <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-setdatasize" title="SetDataSize ( setData )">24.2.1.5 SetDataSize ( <var>setData</var> )</a></li></ol></li><li>+<a href="keyed-collections.html#sec-set-constructor" title="The Set Constructor">24.2.2 The Set Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-set-iterable" title="Set ( [ iterable ] )">24.2.2.1 Set ( [ <var>iterable</var> ] )</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-set-constructor" title="Properties of the Set Constructor">24.2.3 Properties of the Set Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-set.prototype" title="Set.prototype">24.2.3.1 Set.prototype</a></li><li><a href="keyed-collections.html#sec-get-set-%symbol.species%" title="get Set [ %Symbol.species% ]">24.2.3.2 get Set [ %Symbol.species% ]</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-set-prototype-object" title="Properties of the Set Prototype Object">24.2.4 Properties of the Set Prototype Object</a><ol class="toc"><li><a href="keyed-collections.html#sec-set.prototype.add" title="Set.prototype.add ( value )">24.2.4.1 Set.prototype.add ( <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.clear" title="Set.prototype.clear ( )">24.2.4.2 Set.prototype.clear ( )</a></li><li><a href="keyed-collections.html#sec-set.prototype.constructor" title="Set.prototype.constructor">24.2.4.3 Set.prototype.constructor</a></li><li><a href="keyed-collections.html#sec-set.prototype.delete" title="Set.prototype.delete ( value )">24.2.4.4 Set.prototype.delete ( <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.difference" title="Set.prototype.difference ( other )">24.2.4.5 Set.prototype.difference ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.entries" title="Set.prototype.entries ( )">24.2.4.6 Set.prototype.entries ( )</a></li><li><a href="keyed-collections.html#sec-set.prototype.foreach" title="Set.prototype.forEach ( callback [ , thisArg ] )">24.2.4.7 Set.prototype.forEach ( <var>callback</var> [ , <var>thisArg</var> ] )</a></li><li><a href="keyed-collections.html#sec-set.prototype.has" title="Set.prototype.has ( value )">24.2.4.8 Set.prototype.has ( <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.intersection" title="Set.prototype.intersection ( other )">24.2.4.9 Set.prototype.intersection ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.isdisjointfrom" title="Set.prototype.isDisjointFrom ( other )">24.2.4.10 Set.prototype.isDisjointFrom ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.issubsetof" title="Set.prototype.isSubsetOf ( other )">24.2.4.11 Set.prototype.isSubsetOf ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.issupersetof" title="Set.prototype.isSupersetOf ( other )">24.2.4.12 Set.prototype.isSupersetOf ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.keys" title="Set.prototype.keys ( )">24.2.4.13 Set.prototype.keys ( )</a></li><li><a href="keyed-collections.html#sec-get-set.prototype.size" title="get Set.prototype.size">24.2.4.14 get Set.prototype.size</a></li><li><a href="keyed-collections.html#sec-set.prototype.symmetricdifference" title="Set.prototype.symmetricDifference ( other )">24.2.4.15 Set.prototype.symmetricDifference ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.union" title="Set.prototype.union ( other )">24.2.4.16 Set.prototype.union ( <var>other</var> )</a></li><li><a href="keyed-collections.html#sec-set.prototype.values" title="Set.prototype.values ( )">24.2.4.17 Set.prototype.values ( )</a></li><li><a href="keyed-collections.html#sec-set.prototype-%symbol.iterator%" title="Set.prototype [ %Symbol.iterator% ] ( )">24.2.4.18 Set.prototype [ %Symbol.iterator% ] ( )</a></li><li><a href="keyed-collections.html#sec-set.prototype-%symbol.tostringtag%" title="Set.prototype [ %Symbol.toStringTag% ]">24.2.4.19 Set.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="keyed-collections.html#sec-properties-of-set-instances" title="Properties of Set Instances">24.2.5 Properties of Set Instances</a></li><li>+<a href="keyed-collections.html#sec-set-iterator-objects" title="Set Iterator Objects">24.2.6 Set Iterator Objects</a><ol class="toc"><li><a href="keyed-collections.html#sec-createsetiterator" title="CreateSetIterator ( set, kind )">24.2.6.1 CreateSetIterator ( <var>set</var>, <var>kind</var> )</a></li><li>+<a href="keyed-collections.html#sec-%setiteratorprototype%-object" title="The %SetIteratorPrototype% Object">24.2.6.2 The %SetIteratorPrototype% Object</a><ol class="toc"><li><a href="keyed-collections.html#sec-%setiteratorprototype%.next" title="%SetIteratorPrototype%.next ( )">24.2.6.2.1 %SetIteratorPrototype%.next ( )</a></li><li><a href="keyed-collections.html#sec-%setiteratorprototype%-%symbol.tostringtag%" title="%SetIteratorPrototype% [ %Symbol.toStringTag% ]">24.2.6.2.2 %SetIteratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li></ol></li><li>+<a href="keyed-collections.html#sec-weakmap-objects" title="WeakMap Objects">24.3 WeakMap Objects</a><ol class="toc"><li>+<a href="keyed-collections.html#sec-weakmap-constructor" title="The WeakMap Constructor">24.3.1 The WeakMap Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-weakmap-iterable" title="WeakMap ( [ iterable ] )">24.3.1.1 WeakMap ( [ <var>iterable</var> ] )</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-weakmap-constructor" title="Properties of the WeakMap Constructor">24.3.2 Properties of the WeakMap Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-weakmap.prototype" title="WeakMap.prototype">24.3.2.1 WeakMap.prototype</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-weakmap-prototype-object" title="Properties of the WeakMap Prototype Object">24.3.3 Properties of the WeakMap Prototype Object</a><ol class="toc"><li><a href="keyed-collections.html#sec-weakmap.prototype.constructor" title="WeakMap.prototype.constructor">24.3.3.1 WeakMap.prototype.constructor</a></li><li><a href="keyed-collections.html#sec-weakmap.prototype.delete" title="WeakMap.prototype.delete ( key )">24.3.3.2 WeakMap.prototype.delete ( <var>key</var> )</a></li><li><a href="keyed-collections.html#sec-weakmap.prototype.get" title="WeakMap.prototype.get ( key )">24.3.3.3 WeakMap.prototype.get ( <var>key</var> )</a></li><li><a href="keyed-collections.html#sec-weakmap.prototype.has" title="WeakMap.prototype.has ( key )">24.3.3.4 WeakMap.prototype.has ( <var>key</var> )</a></li><li><a href="keyed-collections.html#sec-weakmap.prototype.set" title="WeakMap.prototype.set ( key, value )">24.3.3.5 WeakMap.prototype.set ( <var>key</var>, <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-weakmap.prototype-%symbol.tostringtag%" title="WeakMap.prototype [ %Symbol.toStringTag% ]">24.3.3.6 WeakMap.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="keyed-collections.html#sec-properties-of-weakmap-instances" title="Properties of WeakMap Instances">24.3.4 Properties of WeakMap Instances</a></li></ol></li><li>+<a href="keyed-collections.html#sec-weakset-objects" title="WeakSet Objects">24.4 WeakSet Objects</a><ol class="toc"><li>+<a href="keyed-collections.html#sec-weakset-constructor" title="The WeakSet Constructor">24.4.1 The WeakSet Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-weakset-iterable" title="WeakSet ( [ iterable ] )">24.4.1.1 WeakSet ( [ <var>iterable</var> ] )</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-weakset-constructor" title="Properties of the WeakSet Constructor">24.4.2 Properties of the WeakSet Constructor</a><ol class="toc"><li><a href="keyed-collections.html#sec-weakset.prototype" title="WeakSet.prototype">24.4.2.1 WeakSet.prototype</a></li></ol></li><li>+<a href="keyed-collections.html#sec-properties-of-the-weakset-prototype-object" title="Properties of the WeakSet Prototype Object">24.4.3 Properties of the WeakSet Prototype Object</a><ol class="toc"><li><a href="keyed-collections.html#sec-weakset.prototype.add" title="WeakSet.prototype.add ( value )">24.4.3.1 WeakSet.prototype.add ( <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-weakset.prototype.constructor" title="WeakSet.prototype.constructor">24.4.3.2 WeakSet.prototype.constructor</a></li><li><a href="keyed-collections.html#sec-weakset.prototype.delete" title="WeakSet.prototype.delete ( value )">24.4.3.3 WeakSet.prototype.delete ( <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-weakset.prototype.has" title="WeakSet.prototype.has ( value )">24.4.3.4 WeakSet.prototype.has ( <var>value</var> )</a></li><li><a href="keyed-collections.html#sec-weakset.prototype-%symbol.tostringtag%" title="WeakSet.prototype [ %Symbol.toStringTag% ]">24.4.3.5 WeakSet.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="keyed-collections.html#sec-properties-of-weakset-instances" title="Properties of WeakSet Instances">24.4.4 Properties of WeakSet Instances</a></li></ol></li><li>+<a href="keyed-collections.html#sec-abstract-operations-for-keyed-collections" title="Abstract Operations for Keyed Collections">24.5 Abstract Operations for Keyed Collections</a><ol class="toc"><li><a href="keyed-collections.html#sec-canonicalizekeyedcollectionkey" title="CanonicalizeKeyedCollectionKey ( key )">24.5.1 CanonicalizeKeyedCollectionKey ( <var>key</var> )</a></li></ol></li></ol></li><li>+<a href="structured-data.html#sec-structured-data" title="Structured Data">25 Structured Data</a><ol class="toc"><li>+<a href="structured-data.html#sec-arraybuffer-objects" title="ArrayBuffer Objects">25.1 ArrayBuffer Objects</a><ol class="toc"><li><a href="structured-data.html#sec-arraybuffer-notation" title="Notation">25.1.1 Notation</a></li><li><a href="structured-data.html#sec-fixed-length-and-resizable-arraybuffer-objects" title="Fixed-length and Resizable ArrayBuffer Objects">25.1.2 Fixed-length and Resizable ArrayBuffer Objects</a></li><li>+<a href="structured-data.html#sec-abstract-operations-for-arraybuffer-objects" title="Abstract Operations For ArrayBuffer Objects">25.1.3 Abstract Operations For ArrayBuffer Objects</a><ol class="toc"><li><a href="structured-data.html#sec-allocatearraybuffer" title="AllocateArrayBuffer ( constructor, byteLength [ , maxByteLength ] )">25.1.3.1 AllocateArrayBuffer ( <var>constructor</var>, <var>byteLength</var> [ , <var>maxByteLength</var> ] )</a></li><li><a href="structured-data.html#sec-arraybufferbytelength" title="ArrayBufferByteLength ( arrayBuffer, order )">25.1.3.2 ArrayBufferByteLength ( <var>arrayBuffer</var>, <var>order</var> )</a></li><li><a href="structured-data.html#sec-arraybuffercopyanddetach" title="ArrayBufferCopyAndDetach ( arrayBuffer, newLength, preserveResizability )">25.1.3.3 ArrayBufferCopyAndDetach ( <var>arrayBuffer</var>, <var>newLength</var>, <var>preserveResizability</var> )</a></li><li><a href="structured-data.html#sec-isdetachedbuffer" title="IsDetachedBuffer ( arrayBuffer )">25.1.3.4 IsDetachedBuffer ( <var>arrayBuffer</var> )</a></li><li><a href="structured-data.html#sec-detacharraybuffer" title="DetachArrayBuffer ( arrayBuffer [ , key ] )">25.1.3.5 DetachArrayBuffer ( <var>arrayBuffer</var> [ , <var>key</var> ] )</a></li><li><a href="structured-data.html#sec-clonearraybuffer" title="CloneArrayBuffer ( srcBuffer, srcByteOffset, srcLength )">25.1.3.6 CloneArrayBuffer ( <var>srcBuffer</var>, <var>srcByteOffset</var>, <var>srcLength</var> )</a></li><li><a href="structured-data.html#sec-getarraybuffermaxbytelengthoption" title="GetArrayBufferMaxByteLengthOption ( options )">25.1.3.7 GetArrayBufferMaxByteLengthOption ( <var>options</var> )</a></li><li><a href="structured-data.html#sec-hostresizearraybuffer" title="HostResizeArrayBuffer ( buffer, newByteLength )">25.1.3.8 HostResizeArrayBuffer ( <var>buffer</var>, <var>newByteLength</var> )</a></li><li><a href="structured-data.html#sec-isfixedlengtharraybuffer" title="IsFixedLengthArrayBuffer ( arrayBuffer )">25.1.3.9 IsFixedLengthArrayBuffer ( <var>arrayBuffer</var> )</a></li><li><a href="structured-data.html#sec-isunsignedelementtype" title="IsUnsignedElementType ( type )">25.1.3.10 IsUnsignedElementType ( <var>type</var> )</a></li><li><a href="structured-data.html#sec-isunclampedintegerelementtype" title="IsUnclampedIntegerElementType ( type )">25.1.3.11 IsUnclampedIntegerElementType ( <var>type</var> )</a></li><li><a href="structured-data.html#sec-isbigintelementtype" title="IsBigIntElementType ( type )">25.1.3.12 IsBigIntElementType ( <var>type</var> )</a></li><li><a href="structured-data.html#sec-isnotearconfiguration" title="IsNoTearConfiguration ( type, order )">25.1.3.13 IsNoTearConfiguration ( <var>type</var>, <var>order</var> )</a></li><li><a href="structured-data.html#sec-rawbytestonumeric" title="RawBytesToNumeric ( type, rawBytes, isLittleEndian )">25.1.3.14 RawBytesToNumeric ( <var>type</var>, <var>rawBytes</var>, <var>isLittleEndian</var> )</a></li><li><a href="structured-data.html#sec-getrawbytesfromsharedblock" title="GetRawBytesFromSharedBlock ( block, byteIndex, type, isTypedArray, order )">25.1.3.15 GetRawBytesFromSharedBlock ( <var>block</var>, <var>byteIndex</var>, <var>type</var>, <var>isTypedArray</var>, <var>order</var> )</a></li><li><a href="structured-data.html#sec-getvaluefrombuffer" title="GetValueFromBuffer ( arrayBuffer, byteIndex, type, isTypedArray, order [ , isLittleEndian ] )">25.1.3.16 GetValueFromBuffer ( <var>arrayBuffer</var>, <var>byteIndex</var>, <var>type</var>, <var>isTypedArray</var>, <var>order</var> [ , <var>isLittleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-numerictorawbytes" title="NumericToRawBytes ( type, value, isLittleEndian )">25.1.3.17 NumericToRawBytes ( <var>type</var>, <var>value</var>, <var>isLittleEndian</var> )</a></li><li><a href="structured-data.html#sec-setvalueinbuffer" title="SetValueInBuffer ( arrayBuffer, byteIndex, type, value, isTypedArray, order [ , isLittleEndian ] )">25.1.3.18 SetValueInBuffer ( <var>arrayBuffer</var>, <var>byteIndex</var>, <var>type</var>, <var>value</var>, <var>isTypedArray</var>, <var>order</var> [ , <var>isLittleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-getmodifysetvalueinbuffer" title="GetModifySetValueInBuffer ( arrayBuffer, byteIndex, type, value, op )">25.1.3.19 GetModifySetValueInBuffer ( <var>arrayBuffer</var>, <var>byteIndex</var>, <var>type</var>, <var>value</var>, <var>op</var> )</a></li></ol></li><li>+<a href="structured-data.html#sec-arraybuffer-constructor" title="The ArrayBuffer Constructor">25.1.4 The ArrayBuffer Constructor</a><ol class="toc"><li><a href="structured-data.html#sec-arraybuffer-length" title="ArrayBuffer ( length [ , options ] )">25.1.4.1 ArrayBuffer ( <var>length</var> [ , <var>options</var> ] )</a></li></ol></li><li>+<a href="structured-data.html#sec-properties-of-the-arraybuffer-constructor" title="Properties of the ArrayBuffer Constructor">25.1.5 Properties of the ArrayBuffer Constructor</a><ol class="toc"><li><a href="structured-data.html#sec-arraybuffer.isview" title="ArrayBuffer.isView ( arg )">25.1.5.1 ArrayBuffer.isView ( <var>arg</var> )</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype" title="ArrayBuffer.prototype">25.1.5.2 ArrayBuffer.prototype</a></li><li><a href="structured-data.html#sec-get-arraybuffer-%symbol.species%" title="get ArrayBuffer [ %Symbol.species% ]">25.1.5.3 get ArrayBuffer [ %Symbol.species% ]</a></li></ol></li><li>+<a href="structured-data.html#sec-properties-of-the-arraybuffer-prototype-object" title="Properties of the ArrayBuffer Prototype Object">25.1.6 Properties of the ArrayBuffer Prototype Object</a><ol class="toc"><li><a href="structured-data.html#sec-get-arraybuffer.prototype.bytelength" title="get ArrayBuffer.prototype.byteLength">25.1.6.1 get ArrayBuffer.prototype.byteLength</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype.constructor" title="ArrayBuffer.prototype.constructor">25.1.6.2 ArrayBuffer.prototype.constructor</a></li><li><a href="structured-data.html#sec-get-arraybuffer.prototype.detached" title="get ArrayBuffer.prototype.detached">25.1.6.3 get ArrayBuffer.prototype.detached</a></li><li><a href="structured-data.html#sec-get-arraybuffer.prototype.maxbytelength" title="get ArrayBuffer.prototype.maxByteLength">25.1.6.4 get ArrayBuffer.prototype.maxByteLength</a></li><li><a href="structured-data.html#sec-get-arraybuffer.prototype.resizable" title="get ArrayBuffer.prototype.resizable">25.1.6.5 get ArrayBuffer.prototype.resizable</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype.resize" title="ArrayBuffer.prototype.resize ( newLength )">25.1.6.6 ArrayBuffer.prototype.resize ( <var>newLength</var> )</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype.slice" title="ArrayBuffer.prototype.slice ( start, end )">25.1.6.7 ArrayBuffer.prototype.slice ( <var>start</var>, <var>end</var> )</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype.transfer" title="ArrayBuffer.prototype.transfer ( [ newLength ] )">25.1.6.8 ArrayBuffer.prototype.transfer ( [ <var>newLength</var> ] )</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype.transfertofixedlength" title="ArrayBuffer.prototype.transferToFixedLength ( [ newLength ] )">25.1.6.9 ArrayBuffer.prototype.transferToFixedLength ( [ <var>newLength</var> ] )</a></li><li><a href="structured-data.html#sec-arraybuffer.prototype-%symbol.tostringtag%" title="ArrayBuffer.prototype [ %Symbol.toStringTag% ]">25.1.6.10 ArrayBuffer.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="structured-data.html#sec-properties-of-the-arraybuffer-instances" title="Properties of ArrayBuffer Instances">25.1.7 Properties of ArrayBuffer Instances</a></li><li><a href="structured-data.html#sec-resizable-arraybuffer-guidelines" title="Resizable ArrayBuffer Guidelines">25.1.8 Resizable ArrayBuffer Guidelines</a></li></ol></li><li>+<a href="structured-data.html#sec-sharedarraybuffer-objects" title="SharedArrayBuffer Objects">25.2 SharedArrayBuffer Objects</a><ol class="toc"><li><a href="structured-data.html#sec-fixed-length-and-growable-sharedarraybuffer-objects" title="Fixed-length and Growable SharedArrayBuffer Objects">25.2.1 Fixed-length and Growable SharedArrayBuffer Objects</a></li><li>+<a href="structured-data.html#sec-abstract-operations-for-sharedarraybuffer-objects" title="Abstract Operations for SharedArrayBuffer Objects">25.2.2 Abstract Operations for SharedArrayBuffer Objects</a><ol class="toc"><li><a href="structured-data.html#sec-allocatesharedarraybuffer" title="AllocateSharedArrayBuffer ( constructor, byteLength [ , maxByteLength ] )">25.2.2.1 AllocateSharedArrayBuffer ( <var>constructor</var>, <var>byteLength</var> [ , <var>maxByteLength</var> ] )</a></li><li><a href="structured-data.html#sec-issharedarraybuffer" title="IsSharedArrayBuffer ( obj )">25.2.2.2 IsSharedArrayBuffer ( <var>obj</var> )</a></li><li><a href="structured-data.html#sec-hostgrowsharedarraybuffer" title="HostGrowSharedArrayBuffer ( buffer, newByteLength )">25.2.2.3 HostGrowSharedArrayBuffer ( <var>buffer</var>, <var>newByteLength</var> )</a></li></ol></li><li>+<a href="structured-data.html#sec-sharedarraybuffer-constructor" title="The SharedArrayBuffer Constructor">25.2.3 The SharedArrayBuffer Constructor</a><ol class="toc"><li><a href="structured-data.html#sec-sharedarraybuffer-length" title="SharedArrayBuffer ( length [ , options ] )">25.2.3.1 SharedArrayBuffer ( <var>length</var> [ , <var>options</var> ] )</a></li></ol></li><li>+<a href="structured-data.html#sec-properties-of-the-sharedarraybuffer-constructor" title="Properties of the SharedArrayBuffer Constructor">25.2.4 Properties of the SharedArrayBuffer Constructor</a><ol class="toc"><li><a href="structured-data.html#sec-sharedarraybuffer.prototype" title="SharedArrayBuffer.prototype">25.2.4.1 SharedArrayBuffer.prototype</a></li><li><a href="structured-data.html#sec-sharedarraybuffer-%symbol.species%" title="get SharedArrayBuffer [ %Symbol.species% ]">25.2.4.2 get SharedArrayBuffer [ %Symbol.species% ]</a></li></ol></li><li>+<a href="structured-data.html#sec-properties-of-the-sharedarraybuffer-prototype-object" title="Properties of the SharedArrayBuffer Prototype Object">25.2.5 Properties of the SharedArrayBuffer Prototype Object</a><ol class="toc"><li><a href="structured-data.html#sec-get-sharedarraybuffer.prototype.bytelength" title="get SharedArrayBuffer.prototype.byteLength">25.2.5.1 get SharedArrayBuffer.prototype.byteLength</a></li><li><a href="structured-data.html#sec-sharedarraybuffer.prototype.constructor" title="SharedArrayBuffer.prototype.constructor">25.2.5.2 SharedArrayBuffer.prototype.constructor</a></li><li><a href="structured-data.html#sec-sharedarraybuffer.prototype.grow" title="SharedArrayBuffer.prototype.grow ( newLength )">25.2.5.3 SharedArrayBuffer.prototype.grow ( <var>newLength</var> )</a></li><li><a href="structured-data.html#sec-get-sharedarraybuffer.prototype.growable" title="get SharedArrayBuffer.prototype.growable">25.2.5.4 get SharedArrayBuffer.prototype.growable</a></li><li><a href="structured-data.html#sec-get-sharedarraybuffer.prototype.maxbytelength" title="get SharedArrayBuffer.prototype.maxByteLength">25.2.5.5 get SharedArrayBuffer.prototype.maxByteLength</a></li><li><a href="structured-data.html#sec-sharedarraybuffer.prototype.slice" title="SharedArrayBuffer.prototype.slice ( start, end )">25.2.5.6 SharedArrayBuffer.prototype.slice ( <var>start</var>, <var>end</var> )</a></li><li><a href="structured-data.html#sec-sharedarraybuffer.prototype-%symbol.tostringtag%" title="SharedArrayBuffer.prototype [ %Symbol.toStringTag% ]">25.2.5.7 SharedArrayBuffer.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="structured-data.html#sec-properties-of-the-sharedarraybuffer-instances" title="Properties of SharedArrayBuffer Instances">25.2.6 Properties of SharedArrayBuffer Instances</a></li><li><a href="structured-data.html#sec-growable-sharedarraybuffer-guidelines" title="Growable SharedArrayBuffer Guidelines">25.2.7 Growable SharedArrayBuffer Guidelines</a></li></ol></li><li>+<a href="structured-data.html#sec-dataview-objects" title="DataView Objects">25.3 DataView Objects</a><ol class="toc"><li>+<a href="structured-data.html#sec-abstract-operations-for-dataview-objects" title="Abstract Operations For DataView Objects">25.3.1 Abstract Operations For DataView Objects</a><ol class="toc"><li><a href="structured-data.html#sec-dataview-with-buffer-witness-records" title="DataView With Buffer Witness Records">25.3.1.1 DataView With Buffer Witness Records</a></li><li><a href="structured-data.html#sec-makedataviewwithbufferwitnessrecord" title="MakeDataViewWithBufferWitnessRecord ( obj, order )">25.3.1.2 MakeDataViewWithBufferWitnessRecord ( <var>obj</var>, <var>order</var> )</a></li><li><a href="structured-data.html#sec-getviewbytelength" title="GetViewByteLength ( viewRecord )">25.3.1.3 GetViewByteLength ( <var>viewRecord</var> )</a></li><li><a href="structured-data.html#sec-isviewoutofbounds" title="IsViewOutOfBounds ( viewRecord )">25.3.1.4 IsViewOutOfBounds ( <var>viewRecord</var> )</a></li><li><a href="structured-data.html#sec-getviewvalue" title="GetViewValue ( view, requestIndex, isLittleEndian, type )">25.3.1.5 GetViewValue ( <var>view</var>, <var>requestIndex</var>, <var>isLittleEndian</var>, <var>type</var> )</a></li><li><a href="structured-data.html#sec-setviewvalue" title="SetViewValue ( view, requestIndex, isLittleEndian, type, value )">25.3.1.6 SetViewValue ( <var>view</var>, <var>requestIndex</var>, <var>isLittleEndian</var>, <var>type</var>, <var>value</var> )</a></li></ol></li><li>+<a href="structured-data.html#sec-dataview-constructor" title="The DataView Constructor">25.3.2 The DataView Constructor</a><ol class="toc"><li><a href="structured-data.html#sec-dataview-buffer-byteoffset-bytelength" title="DataView ( buffer [ , byteOffset [ , byteLength ] ] )">25.3.2.1 DataView ( <var>buffer</var> [ , <var>byteOffset</var> [ , <var>byteLength</var> ] ] )</a></li></ol></li><li>+<a href="structured-data.html#sec-properties-of-the-dataview-constructor" title="Properties of the DataView Constructor">25.3.3 Properties of the DataView Constructor</a><ol class="toc"><li><a href="structured-data.html#sec-dataview.prototype" title="DataView.prototype">25.3.3.1 DataView.prototype</a></li></ol></li><li>+<a href="structured-data.html#sec-properties-of-the-dataview-prototype-object" title="Properties of the DataView Prototype Object">25.3.4 Properties of the DataView Prototype Object</a><ol class="toc"><li><a href="structured-data.html#sec-get-dataview.prototype.buffer" title="get DataView.prototype.buffer">25.3.4.1 get DataView.prototype.buffer</a></li><li><a href="structured-data.html#sec-get-dataview.prototype.bytelength" title="get DataView.prototype.byteLength">25.3.4.2 get DataView.prototype.byteLength</a></li><li><a href="structured-data.html#sec-get-dataview.prototype.byteoffset" title="get DataView.prototype.byteOffset">25.3.4.3 get DataView.prototype.byteOffset</a></li><li><a href="structured-data.html#sec-dataview.prototype.constructor" title="DataView.prototype.constructor">25.3.4.4 DataView.prototype.constructor</a></li><li><a href="structured-data.html#sec-dataview.prototype.getbigint64" title="DataView.prototype.getBigInt64 ( byteOffset [ , littleEndian ] )">25.3.4.5 DataView.prototype.getBigInt64 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getbiguint64" title="DataView.prototype.getBigUint64 ( byteOffset [ , littleEndian ] )">25.3.4.6 DataView.prototype.getBigUint64 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getfloat32" title="DataView.prototype.getFloat32 ( byteOffset [ , littleEndian ] )">25.3.4.7 DataView.prototype.getFloat32 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getfloat64" title="DataView.prototype.getFloat64 ( byteOffset [ , littleEndian ] )">25.3.4.8 DataView.prototype.getFloat64 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getint8" title="DataView.prototype.getInt8 ( byteOffset )">25.3.4.9 DataView.prototype.getInt8 ( <var>byteOffset</var> )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getint16" title="DataView.prototype.getInt16 ( byteOffset [ , littleEndian ] )">25.3.4.10 DataView.prototype.getInt16 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getint32" title="DataView.prototype.getInt32 ( byteOffset [ , littleEndian ] )">25.3.4.11 DataView.prototype.getInt32 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getuint8" title="DataView.prototype.getUint8 ( byteOffset )">25.3.4.12 DataView.prototype.getUint8 ( <var>byteOffset</var> )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getuint16" title="DataView.prototype.getUint16 ( byteOffset [ , littleEndian ] )">25.3.4.13 DataView.prototype.getUint16 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.getuint32" title="DataView.prototype.getUint32 ( byteOffset [ , littleEndian ] )">25.3.4.14 DataView.prototype.getUint32 ( <var>byteOffset</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setbigint64" title="DataView.prototype.setBigInt64 ( byteOffset, value [ , littleEndian ] )">25.3.4.15 DataView.prototype.setBigInt64 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setbiguint64" title="DataView.prototype.setBigUint64 ( byteOffset, value [ , littleEndian ] )">25.3.4.16 DataView.prototype.setBigUint64 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setfloat32" title="DataView.prototype.setFloat32 ( byteOffset, value [ , littleEndian ] )">25.3.4.17 DataView.prototype.setFloat32 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setfloat64" title="DataView.prototype.setFloat64 ( byteOffset, value [ , littleEndian ] )">25.3.4.18 DataView.prototype.setFloat64 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setint8" title="DataView.prototype.setInt8 ( byteOffset, value )">25.3.4.19 DataView.prototype.setInt8 ( <var>byteOffset</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setint16" title="DataView.prototype.setInt16 ( byteOffset, value [ , littleEndian ] )">25.3.4.20 DataView.prototype.setInt16 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setint32" title="DataView.prototype.setInt32 ( byteOffset, value [ , littleEndian ] )">25.3.4.21 DataView.prototype.setInt32 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setuint8" title="DataView.prototype.setUint8 ( byteOffset, value )">25.3.4.22 DataView.prototype.setUint8 ( <var>byteOffset</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setuint16" title="DataView.prototype.setUint16 ( byteOffset, value [ , littleEndian ] )">25.3.4.23 DataView.prototype.setUint16 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype.setuint32" title="DataView.prototype.setUint32 ( byteOffset, value [ , littleEndian ] )">25.3.4.24 DataView.prototype.setUint32 ( <var>byteOffset</var>, <var>value</var> [ , <var>littleEndian</var> ] )</a></li><li><a href="structured-data.html#sec-dataview.prototype-%symbol.tostringtag%" title="DataView.prototype [ %Symbol.toStringTag% ]">25.3.4.25 DataView.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="structured-data.html#sec-properties-of-dataview-instances" title="Properties of DataView Instances">25.3.5 Properties of DataView Instances</a></li></ol></li><li>+<a href="structured-data.html#sec-atomics-object" title="The Atomics Object">25.4 The Atomics Object</a><ol class="toc"><li><a href="structured-data.html#sec-waiter-record" title="Waiter Record">25.4.1 Waiter Record</a></li><li><a href="structured-data.html#sec-waiterlist-records" title="WaiterList Records">25.4.2 WaiterList Records</a></li><li>+<a href="structured-data.html#sec-abstract-operations-for-atomics" title="Abstract Operations for Atomics">25.4.3 Abstract Operations for Atomics</a><ol class="toc"><li><a href="structured-data.html#sec-validateintegertypedarray" title="ValidateIntegerTypedArray ( typedArray, waitable )">25.4.3.1 ValidateIntegerTypedArray ( <var>typedArray</var>, <var>waitable</var> )</a></li><li><a href="structured-data.html#sec-validateatomicaccess" title="ValidateAtomicAccess ( taRecord, requestIndex )">25.4.3.2 ValidateAtomicAccess ( <var>taRecord</var>, <var>requestIndex</var> )</a></li><li><a href="structured-data.html#sec-validateatomicaccessonintegertypedarray" title="ValidateAtomicAccessOnIntegerTypedArray ( typedArray, requestIndex [ , waitable ] )">25.4.3.3 ValidateAtomicAccessOnIntegerTypedArray ( <var>typedArray</var>, <var>requestIndex</var> [ , <var>waitable</var> ] )</a></li><li><a href="structured-data.html#sec-revalidateatomicaccess" title="RevalidateAtomicAccess ( typedArray, byteIndexInBuffer )">25.4.3.4 RevalidateAtomicAccess ( <var>typedArray</var>, <var>byteIndexInBuffer</var> )</a></li><li><a href="structured-data.html#sec-getwaiterlist" title="GetWaiterList ( block, i )">25.4.3.5 GetWaiterList ( <var>block</var>, <var>i</var> )</a></li><li><a href="structured-data.html#sec-entercriticalsection" title="EnterCriticalSection ( WL )">25.4.3.6 EnterCriticalSection ( <var>WL</var> )</a></li><li><a href="structured-data.html#sec-leavecriticalsection" title="LeaveCriticalSection ( WL )">25.4.3.7 LeaveCriticalSection ( <var>WL</var> )</a></li><li><a href="structured-data.html#sec-addwaiter" title="AddWaiter ( WL, waiterRecord )">25.4.3.8 AddWaiter ( <var>WL</var>, <var>waiterRecord</var> )</a></li><li><a href="structured-data.html#sec-removewaiter" title="RemoveWaiter ( WL, waiterRecord )">25.4.3.9 RemoveWaiter ( <var>WL</var>, <var>waiterRecord</var> )</a></li><li><a href="structured-data.html#sec-removewaiters" title="RemoveWaiters ( WL, c )">25.4.3.10 RemoveWaiters ( <var>WL</var>, <var>c</var> )</a></li><li><a href="structured-data.html#sec-suspendthisagent" title="SuspendThisAgent ( WL, waiterRecord )">25.4.3.11 SuspendThisAgent ( <var>WL</var>, <var>waiterRecord</var> )</a></li><li><a href="structured-data.html#sec-notifywaiter" title="NotifyWaiter ( WL, waiterRecord )">25.4.3.12 NotifyWaiter ( <var>WL</var>, <var>waiterRecord</var> )</a></li><li><a href="structured-data.html#sec-enqueueresolveinagentjob" title="EnqueueResolveInAgentJob ( agentSignifier, promiseCapability, resolution )">25.4.3.13 EnqueueResolveInAgentJob ( <var>agentSignifier</var>, <var>promiseCapability</var>, <var>resolution</var> )</a></li><li><a href="structured-data.html#sec-dowait" title="DoWait ( mode, typedArray, index, value, timeout )">25.4.3.14 DoWait ( <var>mode</var>, <var>typedArray</var>, <var>index</var>, <var>value</var>, <var>timeout</var> )</a></li><li><a href="structured-data.html#sec-enqueueatomicswaitasynctimeoutjob" title="EnqueueAtomicsWaitAsyncTimeoutJob ( WL, waiterRecord )">25.4.3.15 EnqueueAtomicsWaitAsyncTimeoutJob ( <var>WL</var>, <var>waiterRecord</var> )</a></li><li><a href="structured-data.html#sec-atomiccompareexchangeinsharedblock" title="AtomicCompareExchangeInSharedBlock ( block, byteIndexInBuffer, elementSize, expectedBytes, replacementBytes )">25.4.3.16 AtomicCompareExchangeInSharedBlock ( <var>block</var>, <var>byteIndexInBuffer</var>, <var>elementSize</var>, <var>expectedBytes</var>, <var>replacementBytes</var> )</a></li><li><a href="structured-data.html#sec-atomicreadmodifywrite" title="AtomicReadModifyWrite ( typedArray, index, value, op )">25.4.3.17 AtomicReadModifyWrite ( <var>typedArray</var>, <var>index</var>, <var>value</var>, <var>op</var> )</a></li><li><a href="structured-data.html#sec-bytelistbitwiseop" title="ByteListBitwiseOp ( op, xBytes, yBytes )">25.4.3.18 ByteListBitwiseOp ( <var>op</var>, <var>xBytes</var>, <var>yBytes</var> )</a></li><li><a href="structured-data.html#sec-bytelistequal" title="ByteListEqual ( xBytes, yBytes )">25.4.3.19 ByteListEqual ( <var>xBytes</var>, <var>yBytes</var> )</a></li></ol></li><li><a href="structured-data.html#sec-atomics.add" title="Atomics.add ( typedArray, index, value )">25.4.4 Atomics.add ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics.and" title="Atomics.and ( typedArray, index, value )">25.4.5 Atomics.and ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics.compareexchange" title="Atomics.compareExchange ( typedArray, index, expectedValue, replacementValue )">25.4.6 Atomics.compareExchange ( <var>typedArray</var>, <var>index</var>, <var>expectedValue</var>, <var>replacementValue</var> )</a></li><li><a href="structured-data.html#sec-atomics.exchange" title="Atomics.exchange ( typedArray, index, value )">25.4.7 Atomics.exchange ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics.islockfree" title="Atomics.isLockFree ( size )">25.4.8 Atomics.isLockFree ( <var>size</var> )</a></li><li><a href="structured-data.html#sec-atomics.load" title="Atomics.load ( typedArray, index )">25.4.9 Atomics.load ( <var>typedArray</var>, <var>index</var> )</a></li><li><a href="structured-data.html#sec-atomics.or" title="Atomics.or ( typedArray, index, value )">25.4.10 Atomics.or ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics.store" title="Atomics.store ( typedArray, index, value )">25.4.11 Atomics.store ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics.sub" title="Atomics.sub ( typedArray, index, value )">25.4.12 Atomics.sub ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics.wait" title="Atomics.wait ( typedArray, index, value, timeout )">25.4.13 Atomics.wait ( <var>typedArray</var>, <var>index</var>, <var>value</var>, <var>timeout</var> )</a></li><li><a href="structured-data.html#sec-atomics.waitasync" title="Atomics.waitAsync ( typedArray, index, value, timeout )">25.4.14 Atomics.waitAsync ( <var>typedArray</var>, <var>index</var>, <var>value</var>, <var>timeout</var> )</a></li><li><a href="structured-data.html#sec-atomics.notify" title="Atomics.notify ( typedArray, index, count )">25.4.15 Atomics.notify ( <var>typedArray</var>, <var>index</var>, <var>count</var> )</a></li><li><a href="structured-data.html#sec-atomics.xor" title="Atomics.xor ( typedArray, index, value )">25.4.16 Atomics.xor ( <var>typedArray</var>, <var>index</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-atomics-%symbol.tostringtag%" title="Atomics [ %Symbol.toStringTag% ]">25.4.17 Atomics [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="structured-data.html#sec-json-object" title="The JSON Object">25.5 The JSON Object</a><ol class="toc"><li>+<a href="structured-data.html#sec-json.parse" title="JSON.parse ( text [ , reviver ] )">25.5.1 JSON.parse ( <var>text</var> [ , <var>reviver</var> ] )</a><ol class="toc"><li><a href="structured-data.html#sec-internalizejsonproperty" title="InternalizeJSONProperty ( holder, name, reviver )">25.5.1.1 InternalizeJSONProperty ( <var>holder</var>, <var>name</var>, <var>reviver</var> )</a></li></ol></li><li>+<a href="structured-data.html#sec-json.stringify" title="JSON.stringify ( value [ , replacer [ , space ] ] )">25.5.2 JSON.stringify ( <var>value</var> [ , <var>replacer</var> [ , <var>space</var> ] ] )</a><ol class="toc"><li><a href="structured-data.html#sec-json-serialization-record" title="JSON Serialization Record">25.5.2.1 JSON Serialization Record</a></li><li><a href="structured-data.html#sec-serializejsonproperty" title="SerializeJSONProperty ( state, key, holder )">25.5.2.2 SerializeJSONProperty ( <var>state</var>, <var>key</var>, <var>holder</var> )</a></li><li><a href="structured-data.html#sec-quotejsonstring" title="QuoteJSONString ( value )">25.5.2.3 QuoteJSONString ( <var>value</var> )</a></li><li><a href="structured-data.html#sec-unicodeescape" title="UnicodeEscape ( C )">25.5.2.4 UnicodeEscape ( <var>C</var> )</a></li><li><a href="structured-data.html#sec-serializejsonobject" title="SerializeJSONObject ( state, value )">25.5.2.5 SerializeJSONObject ( <var>state</var>, <var>value</var> )</a></li><li><a href="structured-data.html#sec-serializejsonarray" title="SerializeJSONArray ( state, value )">25.5.2.6 SerializeJSONArray ( <var>state</var>, <var>value</var> )</a></li></ol></li><li><a href="structured-data.html#sec-json-%symbol.tostringtag%" title="JSON [ %Symbol.toStringTag% ]">25.5.3 JSON [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li><li>+<a href="managing-memory.html#sec-managing-memory" title="Managing Memory">26 Managing Memory</a><ol class="toc"><li>+<a href="managing-memory.html#sec-weak-ref-objects" title="WeakRef Objects">26.1 WeakRef Objects</a><ol class="toc"><li>+<a href="managing-memory.html#sec-weak-ref-constructor" title="The WeakRef Constructor">26.1.1 The WeakRef Constructor</a><ol class="toc"><li><a href="managing-memory.html#sec-weak-ref-target" title="WeakRef ( target )">26.1.1.1 WeakRef ( <var>target</var> )</a></li></ol></li><li>+<a href="managing-memory.html#sec-properties-of-the-weak-ref-constructor" title="Properties of the WeakRef Constructor">26.1.2 Properties of the WeakRef Constructor</a><ol class="toc"><li><a href="managing-memory.html#sec-weak-ref.prototype" title="WeakRef.prototype">26.1.2.1 WeakRef.prototype</a></li></ol></li><li>+<a href="managing-memory.html#sec-properties-of-the-weak-ref-prototype-object" title="Properties of the WeakRef Prototype Object">26.1.3 Properties of the WeakRef Prototype Object</a><ol class="toc"><li><a href="managing-memory.html#sec-weak-ref.prototype.constructor" title="WeakRef.prototype.constructor">26.1.3.1 WeakRef.prototype.constructor</a></li><li><a href="managing-memory.html#sec-weak-ref.prototype.deref" title="WeakRef.prototype.deref ( )">26.1.3.2 WeakRef.prototype.deref ( )</a></li><li><a href="managing-memory.html#sec-weak-ref.prototype-%symbol.tostringtag%" title="WeakRef.prototype [ %Symbol.toStringTag% ]">26.1.3.3 WeakRef.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="managing-memory.html#sec-weakref-abstract-operations" title="WeakRef Abstract Operations">26.1.4 WeakRef Abstract Operations</a><ol class="toc"><li><a href="managing-memory.html#sec-weakrefderef" title="WeakRefDeref ( weakRef )">26.1.4.1 WeakRefDeref ( <var>weakRef</var> )</a></li></ol></li><li><a href="managing-memory.html#sec-properties-of-weak-ref-instances" title="Properties of WeakRef Instances">26.1.5 Properties of WeakRef Instances</a></li></ol></li><li>+<a href="managing-memory.html#sec-finalization-registry-objects" title="FinalizationRegistry Objects">26.2 FinalizationRegistry Objects</a><ol class="toc"><li>+<a href="managing-memory.html#sec-finalization-registry-constructor" title="The FinalizationRegistry Constructor">26.2.1 The FinalizationRegistry Constructor</a><ol class="toc"><li><a href="managing-memory.html#sec-finalization-registry-cleanup-callback" title="FinalizationRegistry ( cleanupCallback )">26.2.1.1 FinalizationRegistry ( <var>cleanupCallback</var> )</a></li></ol></li><li>+<a href="managing-memory.html#sec-properties-of-the-finalization-registry-constructor" title="Properties of the FinalizationRegistry Constructor">26.2.2 Properties of the FinalizationRegistry Constructor</a><ol class="toc"><li><a href="managing-memory.html#sec-finalization-registry.prototype" title="FinalizationRegistry.prototype">26.2.2.1 FinalizationRegistry.prototype</a></li></ol></li><li>+<a href="managing-memory.html#sec-properties-of-the-finalization-registry-prototype-object" title="Properties of the FinalizationRegistry Prototype Object">26.2.3 Properties of the FinalizationRegistry Prototype Object</a><ol class="toc"><li><a href="managing-memory.html#sec-finalization-registry.prototype.constructor" title="FinalizationRegistry.prototype.constructor">26.2.3.1 FinalizationRegistry.prototype.constructor</a></li><li><a href="managing-memory.html#sec-finalization-registry.prototype.register" title="FinalizationRegistry.prototype.register ( target, heldValue [ , unregisterToken ] )">26.2.3.2 FinalizationRegistry.prototype.register ( <var>target</var>, <var>heldValue</var> [ , <var>unregisterToken</var> ] )</a></li><li><a href="managing-memory.html#sec-finalization-registry.prototype.unregister" title="FinalizationRegistry.prototype.unregister ( unregisterToken )">26.2.3.3 FinalizationRegistry.prototype.unregister ( <var>unregisterToken</var> )</a></li><li><a href="managing-memory.html#sec-finalization-registry.prototype-%symbol.tostringtag%" title="FinalizationRegistry.prototype [ %Symbol.toStringTag% ]">26.2.3.4 FinalizationRegistry.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="managing-memory.html#sec-properties-of-finalization-registry-instances" title="Properties of FinalizationRegistry Instances">26.2.4 Properties of FinalizationRegistry Instances</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-control-abstraction-objects" title="Control Abstraction Objects">27 Control Abstraction Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-iteration" title="Iteration">27.1 Iteration</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-common-iteration-interfaces" title="Common Iteration Interfaces">27.1.1 Common Iteration Interfaces</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-iterable-interface" title="The Iterable Interface">27.1.1.1 The Iterable Interface</a></li><li><a href="control-abstraction-objects.html#sec-iterator-interface" title="The Iterator Interface">27.1.1.2 The Iterator Interface</a></li><li><a href="control-abstraction-objects.html#sec-asynciterable-interface" title="The Async Iterable Interface">27.1.1.3 The Async Iterable Interface</a></li><li><a href="control-abstraction-objects.html#sec-asynciterator-interface" title="The Async Iterator Interface">27.1.1.4 The Async Iterator Interface</a></li><li><a href="control-abstraction-objects.html#sec-iteratorresult-interface" title="The IteratorResult Interface">27.1.1.5 The IteratorResult Interface</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-iterator-helper-objects" title="Iterator Helper Objects">27.1.2 Iterator Helper Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-%iteratorhelperprototype%-object" title="The %IteratorHelperPrototype% Object">27.1.2.1 The %IteratorHelperPrototype% Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-%iteratorhelperprototype%.next" title="%IteratorHelperPrototype%.next ( )">27.1.2.1.1 %IteratorHelperPrototype%.next ( )</a></li><li><a href="control-abstraction-objects.html#sec-%iteratorhelperprototype%.return" title="%IteratorHelperPrototype%.return ( )">27.1.2.1.2 %IteratorHelperPrototype%.return ( )</a></li><li><a href="control-abstraction-objects.html#sec-%iteratorhelperprototype%-%symbol.tostringtag%" title="%IteratorHelperPrototype% [ %Symbol.toStringTag% ]">27.1.2.1.3 %IteratorHelperPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-iterator-objects" title="Iterator Objects">27.1.3 Iterator Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-iterator-constructor" title="The Iterator Constructor">27.1.3.1 The Iterator Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-iterator" title="Iterator ( )">27.1.3.1.1 Iterator ( )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-the-iterator-constructor" title="Properties of the Iterator Constructor">27.1.3.2 Properties of the Iterator Constructor</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-iterator.from" title="Iterator.from ( O )">27.1.3.2.1 Iterator.from ( <var>O</var> )</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-%wrapforvaliditeratorprototype%-object" title="The %WrapForValidIteratorPrototype% Object">27.1.3.2.1.1 The %WrapForValidIteratorPrototype% Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-%wrapforvaliditeratorprototype%.next" title="%WrapForValidIteratorPrototype%.next ( )">27.1.3.2.1.1.1 %WrapForValidIteratorPrototype%.next ( )</a></li><li><a href="control-abstraction-objects.html#sec-%wrapforvaliditeratorprototype%.return" title="%WrapForValidIteratorPrototype%.return ( )">27.1.3.2.1.1.2 %WrapForValidIteratorPrototype%.return ( )</a></li></ol></li></ol></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype" title="Iterator.prototype">27.1.3.2.2 Iterator.prototype</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-%iterator.prototype%-object" title="The %Iterator.prototype% Object">27.1.4 The %Iterator.prototype% Object</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-iterator.prototype.constructor" title="Iterator.prototype.constructor">27.1.4.1 Iterator.prototype.constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-get-iterator.prototype.constructor" title="get Iterator.prototype.constructor">27.1.4.1.1 get Iterator.prototype.constructor</a></li><li><a href="control-abstraction-objects.html#sec-set-iterator.prototype.constructor" title="set Iterator.prototype.constructor">27.1.4.1.2 set Iterator.prototype.constructor</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.drop" title="Iterator.prototype.drop ( limit )">27.1.4.2 Iterator.prototype.drop ( <var>limit</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.every" title="Iterator.prototype.every ( predicate )">27.1.4.3 Iterator.prototype.every ( <var>predicate</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.filter" title="Iterator.prototype.filter ( predicate )">27.1.4.4 Iterator.prototype.filter ( <var>predicate</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.find" title="Iterator.prototype.find ( predicate )">27.1.4.5 Iterator.prototype.find ( <var>predicate</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.flatmap" title="Iterator.prototype.flatMap ( mapper )">27.1.4.6 Iterator.prototype.flatMap ( <var>mapper</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.foreach" title="Iterator.prototype.forEach ( procedure )">27.1.4.7 Iterator.prototype.forEach ( <var>procedure</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.map" title="Iterator.prototype.map ( mapper )">27.1.4.8 Iterator.prototype.map ( <var>mapper</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.reduce" title="Iterator.prototype.reduce ( reducer [ , initialValue ] )">27.1.4.9 Iterator.prototype.reduce ( <var>reducer</var> [ , <var>initialValue</var> ] )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.some" title="Iterator.prototype.some ( predicate )">27.1.4.10 Iterator.prototype.some ( <var>predicate</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.take" title="Iterator.prototype.take ( limit )">27.1.4.11 Iterator.prototype.take ( <var>limit</var> )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype.toarray" title="Iterator.prototype.toArray ( )">27.1.4.12 Iterator.prototype.toArray ( )</a></li><li><a href="control-abstraction-objects.html#sec-iterator.prototype-%symbol.iterator%" title="Iterator.prototype [ %Symbol.iterator% ] ( )">27.1.4.13 Iterator.prototype [ %Symbol.iterator% ] ( )</a></li><li>+<a href="control-abstraction-objects.html#sec-iterator.prototype-%symbol.tostringtag%" title="Iterator.prototype [ %Symbol.toStringTag% ]">27.1.4.14 Iterator.prototype [ %Symbol.toStringTag% ]</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-get-iterator.prototype-%symbol.tostringtag%" title="get Iterator.prototype [ %Symbol.toStringTag% ]">27.1.4.14.1 get Iterator.prototype [ %Symbol.toStringTag% ]</a></li><li><a href="control-abstraction-objects.html#sec-set-iterator.prototype-%symbol.tostringtag%" title="set Iterator.prototype [ %Symbol.toStringTag% ]">27.1.4.14.2 set Iterator.prototype [ %Symbol.toStringTag% ]</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-asynciteratorprototype" title="The %AsyncIteratorPrototype% Object">27.1.5 The %AsyncIteratorPrototype% Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-%asynciteratorprototype%-%symbol.asynciterator%" title="%AsyncIteratorPrototype% [ %Symbol.asyncIterator% ] ( )">27.1.5.1 %AsyncIteratorPrototype% [ %Symbol.asyncIterator% ] ( )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-async-from-sync-iterator-objects" title="Async-from-Sync Iterator Objects">27.1.6 Async-from-Sync Iterator Objects</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-createasyncfromsynciterator" title="CreateAsyncFromSyncIterator ( syncIteratorRecord )">27.1.6.1 CreateAsyncFromSyncIterator ( <var>syncIteratorRecord</var> )</a></li><li>+<a href="control-abstraction-objects.html#sec-%asyncfromsynciteratorprototype%-object" title="The %AsyncFromSyncIteratorPrototype% Object">27.1.6.2 The %AsyncFromSyncIteratorPrototype% Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-%asyncfromsynciteratorprototype%.next" title="%AsyncFromSyncIteratorPrototype%.next ( [ value ] )">27.1.6.2.1 %AsyncFromSyncIteratorPrototype%.next ( [ <var>value</var> ] )</a></li><li><a href="control-abstraction-objects.html#sec-%asyncfromsynciteratorprototype%.return" title="%AsyncFromSyncIteratorPrototype%.return ( [ value ] )">27.1.6.2.2 %AsyncFromSyncIteratorPrototype%.return ( [ <var>value</var> ] )</a></li><li><a href="control-abstraction-objects.html#sec-%asyncfromsynciteratorprototype%.throw" title="%AsyncFromSyncIteratorPrototype%.throw ( [ value ] )">27.1.6.2.3 %AsyncFromSyncIteratorPrototype%.throw ( [ <var>value</var> ] )</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-properties-of-async-from-sync-iterator-instances" title="Properties of Async-from-Sync Iterator Instances">27.1.6.3 Properties of Async-from-Sync Iterator Instances</a></li><li><a href="control-abstraction-objects.html#sec-asyncfromsynciteratorcontinuation" title="AsyncFromSyncIteratorContinuation ( result, promiseCapability )">27.1.6.4 AsyncFromSyncIteratorContinuation ( <var>result</var>, <var>promiseCapability</var> )</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-promise-objects" title="Promise Objects">27.2 Promise Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-promise-abstract-operations" title="Promise Abstract Operations">27.2.1 Promise Abstract Operations</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-promisecapability-records" title="PromiseCapability Records">27.2.1.1 PromiseCapability Records</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-ifabruptrejectpromise" title="IfAbruptRejectPromise ( value, capability )">27.2.1.1.1 IfAbruptRejectPromise ( <var>value</var>, <var>capability</var> )</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-promisereaction-records" title="PromiseReaction Records">27.2.1.2 PromiseReaction Records</a></li><li>+<a href="control-abstraction-objects.html#sec-createresolvingfunctions" title="CreateResolvingFunctions ( promise )">27.2.1.3 CreateResolvingFunctions ( <var>promise</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-promise-reject-functions" title="Promise Reject Functions">27.2.1.3.1 Promise Reject Functions</a></li><li><a href="control-abstraction-objects.html#sec-promise-resolve-functions" title="Promise Resolve Functions">27.2.1.3.2 Promise Resolve Functions</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-fulfillpromise" title="FulfillPromise ( promise, value )">27.2.1.4 FulfillPromise ( <var>promise</var>, <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-newpromisecapability" title="NewPromiseCapability ( C )">27.2.1.5 NewPromiseCapability ( <var>C</var> )</a></li><li><a href="control-abstraction-objects.html#sec-ispromise" title="IsPromise ( x )">27.2.1.6 IsPromise ( <var>x</var> )</a></li><li><a href="control-abstraction-objects.html#sec-rejectpromise" title="RejectPromise ( promise, reason )">27.2.1.7 RejectPromise ( <var>promise</var>, <var>reason</var> )</a></li><li><a href="control-abstraction-objects.html#sec-triggerpromisereactions" title="TriggerPromiseReactions ( reactions, argument )">27.2.1.8 TriggerPromiseReactions ( <var>reactions</var>, <var>argument</var> )</a></li><li><a href="control-abstraction-objects.html#sec-host-promise-rejection-tracker" title="HostPromiseRejectionTracker ( promise, operation )">27.2.1.9 HostPromiseRejectionTracker ( <var>promise</var>, <var>operation</var> )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-promise-jobs" title="Promise Jobs">27.2.2 Promise Jobs</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-newpromisereactionjob" title="NewPromiseReactionJob ( reaction, argument )">27.2.2.1 NewPromiseReactionJob ( <var>reaction</var>, <var>argument</var> )</a></li><li><a href="control-abstraction-objects.html#sec-newpromiseresolvethenablejob" title="NewPromiseResolveThenableJob ( promiseToResolve, thenable, then )">27.2.2.2 NewPromiseResolveThenableJob ( <var>promiseToResolve</var>, <var>thenable</var>, <var>then</var> )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-promise-constructor" title="The Promise Constructor">27.2.3 The Promise Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-promise-executor" title="Promise ( executor )">27.2.3.1 Promise ( <var>executor</var> )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-the-promise-constructor" title="Properties of the Promise Constructor">27.2.4 Properties of the Promise Constructor</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-promise.all" title="Promise.all ( iterable )">27.2.4.1 Promise.all ( <var>iterable</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-getpromiseresolve" title="GetPromiseResolve ( promiseConstructor )">27.2.4.1.1 GetPromiseResolve ( <var>promiseConstructor</var> )</a></li><li><a href="control-abstraction-objects.html#sec-performpromiseall" title="PerformPromiseAll ( iteratorRecord, constructor, resultCapability, promiseResolve )">27.2.4.1.2 PerformPromiseAll ( <var>iteratorRecord</var>, <var>constructor</var>, <var>resultCapability</var>, <var>promiseResolve</var> )</a></li><li><a href="control-abstraction-objects.html#sec-promise.all-resolve-element-functions" title="Promise.all Resolve Element Functions">27.2.4.1.3 <code>Promise.all</code> Resolve Element Functions</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-promise.allsettled" title="Promise.allSettled ( iterable )">27.2.4.2 Promise.allSettled ( <var>iterable</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-performpromiseallsettled" title="PerformPromiseAllSettled ( iteratorRecord, constructor, resultCapability, promiseResolve )">27.2.4.2.1 PerformPromiseAllSettled ( <var>iteratorRecord</var>, <var>constructor</var>, <var>resultCapability</var>, <var>promiseResolve</var> )</a></li><li><a href="control-abstraction-objects.html#sec-promise.allsettled-resolve-element-functions" title="Promise.allSettled Resolve Element Functions">27.2.4.2.2 <code>Promise.allSettled</code> Resolve Element Functions</a></li><li><a href="control-abstraction-objects.html#sec-promise.allsettled-reject-element-functions" title="Promise.allSettled Reject Element Functions">27.2.4.2.3 <code>Promise.allSettled</code> Reject Element Functions</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-promise.any" title="Promise.any ( iterable )">27.2.4.3 Promise.any ( <var>iterable</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-performpromiseany" title="PerformPromiseAny ( iteratorRecord, constructor, resultCapability, promiseResolve )">27.2.4.3.1 PerformPromiseAny ( <var>iteratorRecord</var>, <var>constructor</var>, <var>resultCapability</var>, <var>promiseResolve</var> )</a></li><li><a href="control-abstraction-objects.html#sec-promise.any-reject-element-functions" title="Promise.any Reject Element Functions">27.2.4.3.2 <code>Promise.any</code> Reject Element Functions</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-promise.prototype" title="Promise.prototype">27.2.4.4 Promise.prototype</a></li><li>+<a href="control-abstraction-objects.html#sec-promise.race" title="Promise.race ( iterable )">27.2.4.5 Promise.race ( <var>iterable</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-performpromiserace" title="PerformPromiseRace ( iteratorRecord, constructor, resultCapability, promiseResolve )">27.2.4.5.1 PerformPromiseRace ( <var>iteratorRecord</var>, <var>constructor</var>, <var>resultCapability</var>, <var>promiseResolve</var> )</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-promise.reject" title="Promise.reject ( r )">27.2.4.6 Promise.reject ( <var>r</var> )</a></li><li>+<a href="control-abstraction-objects.html#sec-promise.resolve" title="Promise.resolve ( x )">27.2.4.7 Promise.resolve ( <var>x</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-promise-resolve" title="PromiseResolve ( C, x )">27.2.4.7.1 PromiseResolve ( <var>C</var>, <var>x</var> )</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-promise.try" title="Promise.try ( callback, ...args )">27.2.4.8 Promise.try ( <var>callback</var>, ...<var>args</var> )</a></li><li><a href="control-abstraction-objects.html#sec-promise.withResolvers" title="Promise.withResolvers ( )">27.2.4.9 Promise.withResolvers ( )</a></li><li><a href="control-abstraction-objects.html#sec-get-promise-%symbol.species%" title="get Promise [ %Symbol.species% ]">27.2.4.10 get Promise [ %Symbol.species% ]</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-the-promise-prototype-object" title="Properties of the Promise Prototype Object">27.2.5 Properties of the Promise Prototype Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-promise.prototype.catch" title="Promise.prototype.catch ( onRejected )">27.2.5.1 Promise.prototype.catch ( <var>onRejected</var> )</a></li><li><a href="control-abstraction-objects.html#sec-promise.prototype.constructor" title="Promise.prototype.constructor">27.2.5.2 Promise.prototype.constructor</a></li><li><a href="control-abstraction-objects.html#sec-promise.prototype.finally" title="Promise.prototype.finally ( onFinally )">27.2.5.3 Promise.prototype.finally ( <var>onFinally</var> )</a></li><li>+<a href="control-abstraction-objects.html#sec-promise.prototype.then" title="Promise.prototype.then ( onFulfilled, onRejected )">27.2.5.4 Promise.prototype.then ( <var>onFulfilled</var>, <var>onRejected</var> )</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-performpromisethen" title="PerformPromiseThen ( promise, onFulfilled, onRejected [ , resultCapability ] )">27.2.5.4.1 PerformPromiseThen ( <var>promise</var>, <var>onFulfilled</var>, <var>onRejected</var> [ , <var>resultCapability</var> ] )</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-promise.prototype-%symbol.tostringtag%" title="Promise.prototype [ %Symbol.toStringTag% ]">27.2.5.5 Promise.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-properties-of-promise-instances" title="Properties of Promise Instances">27.2.6 Properties of Promise Instances</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-generatorfunction-objects" title="GeneratorFunction Objects">27.3 GeneratorFunction Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-generatorfunction-constructor" title="The GeneratorFunction Constructor">27.3.1 The GeneratorFunction Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-generatorfunction" title="GeneratorFunction ( ...parameterArgs, bodyArg )">27.3.1.1 GeneratorFunction ( ...<var>parameterArgs</var>, <var>bodyArg</var> )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-the-generatorfunction-constructor" title="Properties of the GeneratorFunction Constructor">27.3.2 Properties of the GeneratorFunction Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-generatorfunction.prototype" title="GeneratorFunction.prototype">27.3.2.1 GeneratorFunction.prototype</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-the-generatorfunction-prototype-object" title="Properties of the GeneratorFunction Prototype Object">27.3.3 Properties of the GeneratorFunction Prototype Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-generatorfunction.prototype.constructor" title="GeneratorFunction.prototype.constructor">27.3.3.1 GeneratorFunction.prototype.constructor</a></li><li><a href="control-abstraction-objects.html#sec-generatorfunction.prototype.prototype" title="GeneratorFunction.prototype.prototype">27.3.3.2 GeneratorFunction.prototype.prototype</a></li><li><a href="control-abstraction-objects.html#sec-generatorfunction.prototype-%symbol.tostringtag%" title="GeneratorFunction.prototype [ %Symbol.toStringTag% ]">27.3.3.3 GeneratorFunction.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-generatorfunction-instances" title="GeneratorFunction Instances">27.3.4 GeneratorFunction Instances</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-generatorfunction-instances-length" title="length">27.3.4.1 length</a></li><li><a href="control-abstraction-objects.html#sec-generatorfunction-instances-name" title="name">27.3.4.2 name</a></li><li><a href="control-abstraction-objects.html#sec-generatorfunction-instances-prototype" title="prototype">27.3.4.3 prototype</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-objects" title="AsyncGeneratorFunction Objects">27.4 AsyncGeneratorFunction Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-constructor" title="The AsyncGeneratorFunction Constructor">27.4.1 The AsyncGeneratorFunction Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction" title="AsyncGeneratorFunction ( ...parameterArgs, bodyArg )">27.4.1.1 AsyncGeneratorFunction ( ...<var>parameterArgs</var>, <var>bodyArg</var> )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-asyncgeneratorfunction" title="Properties of the AsyncGeneratorFunction Constructor">27.4.2 Properties of the AsyncGeneratorFunction Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-prototype" title="AsyncGeneratorFunction.prototype">27.4.2.1 AsyncGeneratorFunction.prototype</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-properties-of-asyncgeneratorfunction-prototype" title="Properties of the AsyncGeneratorFunction Prototype Object">27.4.3 Properties of the AsyncGeneratorFunction Prototype Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-prototype-constructor" title="AsyncGeneratorFunction.prototype.constructor">27.4.3.1 AsyncGeneratorFunction.prototype.constructor</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-prototype-prototype" title="AsyncGeneratorFunction.prototype.prototype">27.4.3.2 AsyncGeneratorFunction.prototype.prototype</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-prototype-%symbol.tostringtag%" title="AsyncGeneratorFunction.prototype [ %Symbol.toStringTag% ]">27.4.3.3 AsyncGeneratorFunction.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-instances" title="AsyncGeneratorFunction Instances">27.4.4 AsyncGeneratorFunction Instances</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-instance-length" title="length">27.4.4.1 length</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-instance-name" title="name">27.4.4.2 name</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorfunction-instance-prototype" title="prototype">27.4.4.3 prototype</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-generator-objects" title="Generator Objects">27.5 Generator Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-properties-of-generator-prototype" title="The %GeneratorPrototype% Object">27.5.1 The %GeneratorPrototype% Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-generator.prototype.constructor" title="%GeneratorPrototype%.constructor">27.5.1.1 %GeneratorPrototype%.constructor</a></li><li><a href="control-abstraction-objects.html#sec-generator.prototype.next" title="%GeneratorPrototype%.next ( value )">27.5.1.2 %GeneratorPrototype%.next ( <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-generator.prototype.return" title="%GeneratorPrototype%.return ( value )">27.5.1.3 %GeneratorPrototype%.return ( <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-generator.prototype.throw" title="%GeneratorPrototype%.throw ( exception )">27.5.1.4 %GeneratorPrototype%.throw ( <var>exception</var> )</a></li><li><a href="control-abstraction-objects.html#sec-generator.prototype-%symbol.tostringtag%" title="%GeneratorPrototype% [ %Symbol.toStringTag% ]">27.5.1.5 %GeneratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-properties-of-generator-instances" title="Properties of Generator Instances">27.5.2 Properties of Generator Instances</a></li><li>+<a href="control-abstraction-objects.html#sec-generator-abstract-operations" title="Generator Abstract Operations">27.5.3 Generator Abstract Operations</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-generatorstart" title="GeneratorStart ( generator, generatorBody )">27.5.3.1 GeneratorStart ( <var>generator</var>, <var>generatorBody</var> )</a></li><li><a href="control-abstraction-objects.html#sec-generatorvalidate" title="GeneratorValidate ( generator, generatorBrand )">27.5.3.2 GeneratorValidate ( <var>generator</var>, <var>generatorBrand</var> )</a></li><li><a href="control-abstraction-objects.html#sec-generatorresume" title="GeneratorResume ( generator, value, generatorBrand )">27.5.3.3 GeneratorResume ( <var>generator</var>, <var>value</var>, <var>generatorBrand</var> )</a></li><li><a href="control-abstraction-objects.html#sec-generatorresumeabrupt" title="GeneratorResumeAbrupt ( generator, abruptCompletion, generatorBrand )">27.5.3.4 GeneratorResumeAbrupt ( <var>generator</var>, <var>abruptCompletion</var>, <var>generatorBrand</var> )</a></li><li><a href="control-abstraction-objects.html#sec-getgeneratorkind" title="GetGeneratorKind ( )">27.5.3.5 GetGeneratorKind ( )</a></li><li><a href="control-abstraction-objects.html#sec-generatoryield" title="GeneratorYield ( iteratorResult )">27.5.3.6 GeneratorYield ( <var>iteratorResult</var> )</a></li><li><a href="control-abstraction-objects.html#sec-yield" title="Yield ( value )">27.5.3.7 Yield ( <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-createiteratorfromclosure" title="CreateIteratorFromClosure ( closure, generatorBrand, generatorPrototype [ , extraSlots ] )">27.5.3.8 CreateIteratorFromClosure ( <var>closure</var>, <var>generatorBrand</var>, <var>generatorPrototype</var> [ , <var>extraSlots</var> ] )</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-asyncgenerator-objects" title="AsyncGenerator Objects">27.6 AsyncGenerator Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-properties-of-asyncgenerator-prototype" title="The %AsyncGeneratorPrototype% Object">27.6.1 The %AsyncGeneratorPrototype% Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-asyncgenerator-prototype-constructor" title="%AsyncGeneratorPrototype%.constructor">27.6.1.1 %AsyncGeneratorPrototype%.constructor</a></li><li><a href="control-abstraction-objects.html#sec-asyncgenerator-prototype-next" title="%AsyncGeneratorPrototype%.next ( value )">27.6.1.2 %AsyncGeneratorPrototype%.next ( <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgenerator-prototype-return" title="%AsyncGeneratorPrototype%.return ( value )">27.6.1.3 %AsyncGeneratorPrototype%.return ( <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgenerator-prototype-throw" title="%AsyncGeneratorPrototype%.throw ( exception )">27.6.1.4 %AsyncGeneratorPrototype%.throw ( <var>exception</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgenerator-prototype-%symbol.tostringtag%" title="%AsyncGeneratorPrototype% [ %Symbol.toStringTag% ]">27.6.1.5 %AsyncGeneratorPrototype% [ %Symbol.toStringTag% ]</a></li></ol></li><li><a href="control-abstraction-objects.html#sec-properties-of-asyncgenerator-intances" title="Properties of AsyncGenerator Instances">27.6.2 Properties of AsyncGenerator Instances</a></li><li>+<a href="control-abstraction-objects.html#sec-asyncgenerator-abstract-operations" title="AsyncGenerator Abstract Operations">27.6.3 AsyncGenerator Abstract Operations</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-asyncgeneratorrequest-records" title="AsyncGeneratorRequest Records">27.6.3.1 AsyncGeneratorRequest Records</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorstart" title="AsyncGeneratorStart ( generator, generatorBody )">27.6.3.2 AsyncGeneratorStart ( <var>generator</var>, <var>generatorBody</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorvalidate" title="AsyncGeneratorValidate ( generator, generatorBrand )">27.6.3.3 AsyncGeneratorValidate ( <var>generator</var>, <var>generatorBrand</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorenqueue" title="AsyncGeneratorEnqueue ( generator, completion, promiseCapability )">27.6.3.4 AsyncGeneratorEnqueue ( <var>generator</var>, <var>completion</var>, <var>promiseCapability</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorcompletestep" title="AsyncGeneratorCompleteStep ( generator, completion, done [ , realm ] )">27.6.3.5 AsyncGeneratorCompleteStep ( <var>generator</var>, <var>completion</var>, <var>done</var> [ , <var>realm</var> ] )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorresume" title="AsyncGeneratorResume ( generator, completion )">27.6.3.6 AsyncGeneratorResume ( <var>generator</var>, <var>completion</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorunwrapyieldresumption" title="AsyncGeneratorUnwrapYieldResumption ( resumptionValue )">27.6.3.7 AsyncGeneratorUnwrapYieldResumption ( <var>resumptionValue</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratoryield" title="AsyncGeneratorYield ( value )">27.6.3.8 AsyncGeneratorYield ( <var>value</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratorawaitreturn" title="AsyncGeneratorAwaitReturn ( generator )">27.6.3.9 AsyncGeneratorAwaitReturn ( <var>generator</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncgeneratordrainqueue" title="AsyncGeneratorDrainQueue ( generator )">27.6.3.10 AsyncGeneratorDrainQueue ( <var>generator</var> )</a></li><li><a href="control-abstraction-objects.html#sec-createasynciteratorfromclosure" title="CreateAsyncIteratorFromClosure ( closure, generatorBrand, generatorPrototype )">27.6.3.11 CreateAsyncIteratorFromClosure ( <var>closure</var>, <var>generatorBrand</var>, <var>generatorPrototype</var> )</a></li></ol></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-async-function-objects" title="AsyncFunction Objects">27.7 AsyncFunction Objects</a><ol class="toc"><li>+<a href="control-abstraction-objects.html#sec-async-function-constructor" title="The AsyncFunction Constructor">27.7.1 The AsyncFunction Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-async-function-constructor-arguments" title="AsyncFunction ( ...parameterArgs, bodyArg )">27.7.1.1 AsyncFunction ( ...<var>parameterArgs</var>, <var>bodyArg</var> )</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-async-function-constructor-properties" title="Properties of the AsyncFunction Constructor">27.7.2 Properties of the AsyncFunction Constructor</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-async-function-constructor-prototype" title="AsyncFunction.prototype">27.7.2.1 AsyncFunction.prototype</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-async-function-prototype-properties" title="Properties of the AsyncFunction Prototype Object">27.7.3 Properties of the AsyncFunction Prototype Object</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-async-function-prototype-properties-constructor" title="AsyncFunction.prototype.constructor">27.7.3.1 AsyncFunction.prototype.constructor</a></li><li><a href="control-abstraction-objects.html#sec-async-function-prototype-%symbol.tostringtag%" title="AsyncFunction.prototype [ %Symbol.toStringTag% ]">27.7.3.2 AsyncFunction.prototype [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-async-function-instances" title="AsyncFunction Instances">27.7.4 AsyncFunction Instances</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-async-function-instances-length" title="length">27.7.4.1 length</a></li><li><a href="control-abstraction-objects.html#sec-async-function-instances-name" title="name">27.7.4.2 name</a></li></ol></li><li>+<a href="control-abstraction-objects.html#sec-async-functions-abstract-operations" title="Async Functions Abstract Operations">27.7.5 Async Functions Abstract Operations</a><ol class="toc"><li><a href="control-abstraction-objects.html#sec-async-functions-abstract-operations-async-function-start" title="AsyncFunctionStart ( promiseCapability, asyncFunctionBody )">27.7.5.1 AsyncFunctionStart ( <var>promiseCapability</var>, <var>asyncFunctionBody</var> )</a></li><li><a href="control-abstraction-objects.html#sec-asyncblockstart" title="AsyncBlockStart ( promiseCapability, asyncBody, asyncContext )">27.7.5.2 AsyncBlockStart ( <var>promiseCapability</var>, <var>asyncBody</var>, <var>asyncContext</var> )</a></li><li><a href="control-abstraction-objects.html#await" title="Await ( value )">27.7.5.3 Await ( <var>value</var> )</a></li></ol></li></ol></li></ol></li><li>+<a href="reflection.html#sec-reflection" title="Reflection">28 Reflection</a><ol class="toc"><li>+<a href="reflection.html#sec-reflect-object" title="The Reflect Object">28.1 The Reflect Object</a><ol class="toc"><li><a href="reflection.html#sec-reflect.apply" title="Reflect.apply ( target, thisArgument, argumentsList )">28.1.1 Reflect.apply ( <var>target</var>, <var>thisArgument</var>, <var>argumentsList</var> )</a></li><li><a href="reflection.html#sec-reflect.construct" title="Reflect.construct ( target, argumentsList [ , newTarget ] )">28.1.2 Reflect.construct ( <var>target</var>, <var>argumentsList</var> [ , <var>newTarget</var> ] )</a></li><li><a href="reflection.html#sec-reflect.defineproperty" title="Reflect.defineProperty ( target, propertyKey, attributes )">28.1.3 Reflect.defineProperty ( <var>target</var>, <var>propertyKey</var>, <var>attributes</var> )</a></li><li><a href="reflection.html#sec-reflect.deleteproperty" title="Reflect.deleteProperty ( target, propertyKey )">28.1.4 Reflect.deleteProperty ( <var>target</var>, <var>propertyKey</var> )</a></li><li><a href="reflection.html#sec-reflect.get" title="Reflect.get ( target, propertyKey [ , receiver ] )">28.1.5 Reflect.get ( <var>target</var>, <var>propertyKey</var> [ , <var>receiver</var> ] )</a></li><li><a href="reflection.html#sec-reflect.getownpropertydescriptor" title="Reflect.getOwnPropertyDescriptor ( target, propertyKey )">28.1.6 Reflect.getOwnPropertyDescriptor ( <var>target</var>, <var>propertyKey</var> )</a></li><li><a href="reflection.html#sec-reflect.getprototypeof" title="Reflect.getPrototypeOf ( target )">28.1.7 Reflect.getPrototypeOf ( <var>target</var> )</a></li><li><a href="reflection.html#sec-reflect.has" title="Reflect.has ( target, propertyKey )">28.1.8 Reflect.has ( <var>target</var>, <var>propertyKey</var> )</a></li><li><a href="reflection.html#sec-reflect.isextensible" title="Reflect.isExtensible ( target )">28.1.9 Reflect.isExtensible ( <var>target</var> )</a></li><li><a href="reflection.html#sec-reflect.ownkeys" title="Reflect.ownKeys ( target )">28.1.10 Reflect.ownKeys ( <var>target</var> )</a></li><li><a href="reflection.html#sec-reflect.preventextensions" title="Reflect.preventExtensions ( target )">28.1.11 Reflect.preventExtensions ( <var>target</var> )</a></li><li><a href="reflection.html#sec-reflect.set" title="Reflect.set ( target, propertyKey, V [ , receiver ] )">28.1.12 Reflect.set ( <var>target</var>, <var>propertyKey</var>, <var>V</var> [ , <var>receiver</var> ] )</a></li><li><a href="reflection.html#sec-reflect.setprototypeof" title="Reflect.setPrototypeOf ( target, proto )">28.1.13 Reflect.setPrototypeOf ( <var>target</var>, <var>proto</var> )</a></li><li><a href="reflection.html#sec-reflect-%symbol.tostringtag%" title="Reflect [ %Symbol.toStringTag% ]">28.1.14 Reflect [ %Symbol.toStringTag% ]</a></li></ol></li><li>+<a href="reflection.html#sec-proxy-objects" title="Proxy Objects">28.2 Proxy Objects</a><ol class="toc"><li>+<a href="reflection.html#sec-proxy-constructor" title="The Proxy Constructor">28.2.1 The Proxy Constructor</a><ol class="toc"><li><a href="reflection.html#sec-proxy-target-handler" title="Proxy ( target, handler )">28.2.1.1 Proxy ( <var>target</var>, <var>handler</var> )</a></li></ol></li><li>+<a href="reflection.html#sec-properties-of-the-proxy-constructor" title="Properties of the Proxy Constructor">28.2.2 Properties of the Proxy Constructor</a><ol class="toc"><li><a href="reflection.html#sec-proxy.revocable" title="Proxy.revocable ( target, handler )">28.2.2.1 Proxy.revocable ( <var>target</var>, <var>handler</var> )</a></li></ol></li></ol></li><li>+<a href="reflection.html#sec-module-namespace-objects" title="Module Namespace Objects">28.3 Module Namespace Objects</a><ol class="toc"><li><a href="reflection.html#sec-%symbol.tostringtag%" title="%Symbol.toStringTag%">28.3.1 %Symbol.toStringTag%</a></li></ol></li></ol></li><li>+<a href="memory-model.html#sec-memory-model" title="Memory Model">29 Memory Model</a><ol class="toc"><li><a href="memory-model.html#sec-memory-model-fundamentals" title="Memory Model Fundamentals">29.1 Memory Model Fundamentals</a></li><li><a href="memory-model.html#sec-agent-event-records" title="Agent Events Records">29.2 Agent Events Records</a></li><li><a href="memory-model.html#sec-chosen-value-records" title="Chosen Value Records">29.3 Chosen Value Records</a></li><li><a href="memory-model.html#sec-candidate-executions" title="Candidate Executions">29.4 Candidate Executions</a></li><li>+<a href="memory-model.html#sec-abstract-operations-for-the-memory-model" title="Abstract Operations for the Memory Model">29.5 Abstract Operations for the Memory Model</a><ol class="toc"><li><a href="memory-model.html#sec-event-set" title="EventSet ( execution )">29.5.1 EventSet ( <var>execution</var> )</a></li><li><a href="memory-model.html#sec-sharedatablockeventset" title="SharedDataBlockEventSet ( execution )">29.5.2 SharedDataBlockEventSet ( <var>execution</var> )</a></li><li><a href="memory-model.html#sec-hosteventset" title="HostEventSet ( execution )">29.5.3 HostEventSet ( <var>execution</var> )</a></li><li><a href="memory-model.html#sec-composewriteeventbytes" title="ComposeWriteEventBytes ( execution, byteIndex, Ws )">29.5.4 ComposeWriteEventBytes ( <var>execution</var>, <var>byteIndex</var>, <var>Ws</var> )</a></li><li><a href="memory-model.html#sec-valueofreadevent" title="ValueOfReadEvent ( execution, R )">29.5.5 ValueOfReadEvent ( <var>execution</var>, <var>R</var> )</a></li></ol></li><li>+<a href="memory-model.html#sec-relations-of-candidate-executions" title="Relations of Candidate Executions">29.6 Relations of Candidate Executions</a><ol class="toc"><li><a href="memory-model.html#sec-agent-order" title="is-agent-order-before">29.6.1 is-agent-order-before</a></li><li><a href="memory-model.html#sec-reads-bytes-from" title="reads-bytes-from">29.6.2 reads-bytes-from</a></li><li><a href="memory-model.html#sec-reads-from" title="reads-from">29.6.3 reads-from</a></li><li><a href="memory-model.html#sec-host-synchronizes-with" title="host-synchronizes-with">29.6.4 host-synchronizes-with</a></li><li><a href="memory-model.html#sec-synchronizes-with" title="synchronizes-with">29.6.5 synchronizes-with</a></li><li><a href="memory-model.html#sec-happens-before" title="happens-before">29.6.6 happens-before</a></li></ol></li><li>+<a href="memory-model.html#sec-properties-of-valid-executions" title="Properties of Valid Executions">29.7 Properties of Valid Executions</a><ol class="toc"><li><a href="memory-model.html#sec-valid-chosen-reads" title="Valid Chosen Reads">29.7.1 Valid Chosen Reads</a></li><li><a href="memory-model.html#sec-coherent-reads" title="Coherent Reads">29.7.2 Coherent Reads</a></li><li><a href="memory-model.html#sec-tear-free-aligned-reads" title="Tear Free Reads">29.7.3 Tear Free Reads</a></li><li><a href="memory-model.html#sec-memory-order" title="Sequentially Consistent Atomics">29.7.4 Sequentially Consistent Atomics</a></li><li><a href="memory-model.html#sec-valid-executions" title="Valid Executions">29.7.5 Valid Executions</a></li></ol></li><li><a href="memory-model.html#sec-races" title="Races">29.8 Races</a></li><li><a href="memory-model.html#sec-data-races" title="Data Races">29.9 Data Races</a></li><li><a href="memory-model.html#sec-data-race-freedom" title="Data Race Freedom">29.10 Data Race Freedom</a></li><li><a href="memory-model.html#sec-shared-memory-guidelines" title="Shared Memory Guidelines">29.11 Shared Memory Guidelines</a></li></ol></li><li>+<a href="grammar-summary.html#sec-grammar-summary" title="Grammar Summary">A Grammar Summary</a><ol class="toc"><li><a href="grammar-summary.html#sec-lexical-grammar" title="Lexical Grammar">A.1 Lexical Grammar</a></li><li><a href="grammar-summary.html#sec-expressions" title="Expressions">A.2 Expressions</a></li><li><a href="grammar-summary.html#sec-statements" title="Statements">A.3 Statements</a></li><li><a href="grammar-summary.html#sec-functions-and-classes" title="Functions and Classes">A.4 Functions and Classes</a></li><li><a href="grammar-summary.html#sec-scripts-and-modules" title="Scripts and Modules">A.5 Scripts and Modules</a></li><li><a href="grammar-summary.html#sec-number-conversions" title="Number Conversions">A.6 Number Conversions</a></li><li><a href="grammar-summary.html#sec-time-zone-offset-string-format" title="Time Zone Offset String Format">A.7 Time Zone Offset String Format</a></li><li><a href="grammar-summary.html#sec-regular-expressions" title="Regular Expressions">A.8 Regular Expressions</a></li></ol></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers" title="Additional ECMAScript Features for Web Browsers">B Additional ECMAScript Features for Web Browsers</a><ol class="toc"><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-syntax" title="Additional Syntax">B.1 Additional Syntax</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-html-like-comments" title="HTML-like Comments">B.1.1 HTML-like Comments</a></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-regular-expressions-patterns" title="Regular Expressions Patterns">B.1.2 Regular Expressions Patterns</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-patterns-static-semantics-early-errors-annexb" title="Static Semantics: Early Errors">B.1.2.1 SS: Early Errors</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-countleftcapturingparens-annexb" title="Static Semantics: CountLeftCapturingParensWithin and CountLeftCapturingParensBefore">B.1.2.2 SS: CountLeftCapturingParensWithin and CountLeftCapturingParensBefore</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-patterns-static-semantics-is-character-class-annexb" title="Static Semantics: IsCharacterClass">B.1.2.3 SS: IsCharacterClass</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-patterns-static-semantics-character-value-annexb" title="Static Semantics: CharacterValue">B.1.2.4 SS: CharacterValue</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-compilesubpattern-annexb" title="Runtime Semantics: CompileSubpattern">B.1.2.5 RS: CompileSubpattern</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-compileassertion-annexb" title="Runtime Semantics: CompileAssertion">B.1.2.6 RS: CompileAssertion</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-compileatom-annexb" title="Runtime Semantics: CompileAtom">B.1.2.7 RS: CompileAtom</a></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-compiletocharset-annexb" title="Runtime Semantics: CompileToCharSet">B.1.2.8 RS: CompileToCharSet</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-runtime-semantics-characterrangeorunion-abstract-operation" title="CharacterRangeOrUnion ( rer, A, B )">B.1.2.8.1 CharacterRangeOrUnion ( <var>rer</var>, <var>A</var>, <var>B</var> )</a></li></ol></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-parsepattern-annexb" title="Static Semantics: ParsePattern ( patternText, u, v )">B.1.2.9 SS: ParsePattern ( <var>patternText</var>, <var>u</var>, <var>v</var> )</a></li></ol></li></ol></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-built-in-properties" title="Additional Built-in Properties">B.2 Additional Built-in Properties</a><ol class="toc"><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-properties-of-the-global-object" title="Additional Properties of the Global Object">B.2.1 Additional Properties of the Global Object</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-escape-string" title="escape ( string )">B.2.1.1 escape ( <var>string</var> )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-unescape-string" title="unescape ( string )">B.2.1.2 unescape ( <var>string</var> )</a></li></ol></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-properties-of-the-string.prototype-object" title="Additional Properties of the String.prototype Object">B.2.2 Additional Properties of the String.prototype Object</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.substr" title="String.prototype.substr ( start, length )">B.2.2.1 String.prototype.substr ( <var>start</var>, <var>length</var> )</a></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.anchor" title="String.prototype.anchor ( name )">B.2.2.2 String.prototype.anchor ( <var>name</var> )</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-createhtml" title="CreateHTML ( string, tag, attribute, value )">B.2.2.2.1 CreateHTML ( <var>string</var>, <var>tag</var>, <var>attribute</var>, <var>value</var> )</a></li></ol></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.big" title="String.prototype.big ( )">B.2.2.3 String.prototype.big ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.blink" title="String.prototype.blink ( )">B.2.2.4 String.prototype.blink ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.bold" title="String.prototype.bold ( )">B.2.2.5 String.prototype.bold ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.fixed" title="String.prototype.fixed ( )">B.2.2.6 String.prototype.fixed ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.fontcolor" title="String.prototype.fontcolor ( colour )">B.2.2.7 String.prototype.fontcolor ( <var>colour</var> )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.fontsize" title="String.prototype.fontsize ( size )">B.2.2.8 String.prototype.fontsize ( <var>size</var> )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.italics" title="String.prototype.italics ( )">B.2.2.9 String.prototype.italics ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.link" title="String.prototype.link ( url )">B.2.2.10 String.prototype.link ( <var>url</var> )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.small" title="String.prototype.small ( )">B.2.2.11 String.prototype.small ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.strike" title="String.prototype.strike ( )">B.2.2.12 String.prototype.strike ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.sub" title="String.prototype.sub ( )">B.2.2.13 String.prototype.sub ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-string.prototype.sup" title="String.prototype.sup ( )">B.2.2.14 String.prototype.sup ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#String.prototype.trimleft" title="String.prototype.trimLeft ( )">B.2.2.15 String.prototype.trimLeft ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#String.prototype.trimright" title="String.prototype.trimRight ( )">B.2.2.16 String.prototype.trimRight ( )</a></li></ol></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-properties-of-the-date.prototype-object" title="Additional Properties of the Date.prototype Object">B.2.3 Additional Properties of the Date.prototype Object</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-date.prototype.getyear" title="Date.prototype.getYear ( )">B.2.3.1 Date.prototype.getYear ( )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-date.prototype.setyear" title="Date.prototype.setYear ( year )">B.2.3.2 Date.prototype.setYear ( <var>year</var> )</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-date.prototype.togmtstring" title="Date.prototype.toGMTString ( )">B.2.3.3 Date.prototype.toGMTString ( )</a></li></ol></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-additional-properties-of-the-regexp.prototype-object" title="Additional Properties of the RegExp.prototype Object">B.2.4 Additional Properties of the RegExp.prototype Object</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-regexp.prototype.compile" title="RegExp.prototype.compile ( pattern, flags )">B.2.4.1 RegExp.prototype.compile ( <var>pattern</var>, <var>flags</var> )</a></li></ol></li></ol></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-other-additional-features" title="Other Additional Features">B.3 Other Additional Features</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations" title="Labelled Function Declarations">B.3.1 Labelled Function Declarations</a></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-block-level-function-declarations-web-legacy-compatibility-semantics" title="Block-Level Function Declarations Web Legacy Compatibility Semantics">B.3.2 Block-Level Function Declarations Web Legacy Compatibility Semantics</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-functiondeclarationinstantiation" title="Changes to FunctionDeclarationInstantiation">B.3.2.1 Changes to FunctionDeclarationInstantiation</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-globaldeclarationinstantiation" title="Changes to GlobalDeclarationInstantiation">B.3.2.2 Changes to GlobalDeclarationInstantiation</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-evaldeclarationinstantiation" title="Changes to EvalDeclarationInstantiation">B.3.2.3 Changes to EvalDeclarationInstantiation</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-block-duplicates-allowed-static-semantics" title="Changes to Block Static Semantics: Early Errors">B.3.2.4 Changes to Block SS: Early Errors</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-switch-duplicates-allowed-static-semantics" title="Changes to switch Statement Static Semantics: Early Errors">B.3.2.5 Changes to <code>switch</code> Statement SS: Early Errors</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-blockdeclarationinstantiation" title="Changes to BlockDeclarationInstantiation">B.3.2.6 Changes to BlockDeclarationInstantiation</a></li></ol></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-functiondeclarations-in-ifstatement-statement-clauses" title="FunctionDeclarations in IfStatement Statement Clauses">B.3.3 FunctionDeclarations in IfStatement Statement Clauses</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-variablestatements-in-catch-blocks" title="VariableStatements in Catch Blocks">B.3.4 VariableStatements in Catch Blocks</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-initializers-in-forin-statement-heads" title="Initializers in ForIn Statement Heads">B.3.5 Initializers in ForIn Statement Heads</a></li><li>+<a href="additional-ecmascript-features-for-web-browsers.html#sec-IsHTMLDDA-internal-slot" title="The [[IsHTMLDDA]] Internal Slot">B.3.6 The <var class="field">[[IsHTMLDDA]]</var> Internal Slot</a><ol class="toc"><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-IsHTMLDDA-internal-slot-to-boolean" title="Changes to ToBoolean">B.3.6.1 Changes to ToBoolean</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-IsHTMLDDA-internal-slot-aec" title="Changes to IsLooselyEqual">B.3.6.2 Changes to IsLooselyEqual</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-IsHTMLDDA-internal-slot-typeof" title="Changes to the typeof Operator">B.3.6.3 Changes to the <code>typeof</code> Operator</a></li></ol></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-host-make-job-callback" title="Non-default behaviour in HostMakeJobCallback">B.3.7 Non-default behaviour in HostMakeJobCallback</a></li><li><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-host-ensure-can-add-private-field" title="Non-default behaviour in HostEnsureCanAddPrivateElement">B.3.8 Non-default behaviour in HostEnsureCanAddPrivateElement</a></li></ol></li></ol></li><li><a href="strict-mode-of-ecmascript.html#sec-strict-mode-of-ecmascript" title="The Strict Mode of ECMAScript">C The Strict Mode of ECMAScript</a></li><li>+<a href="host-layering-points.html#sec-host-layering-points" title="Host Layering Points">D Host Layering Points</a><ol class="toc"><li><a href="host-layering-points.html#sec-host-hooks-summary" title="Host Hooks">D.1 Host Hooks</a></li><li><a href="host-layering-points.html#sec-host-defined-fields-summary" title="Host-defined Fields">D.2 Host-defined Fields</a></li><li><a href="host-layering-points.html#sec-host-defined-objects-summary" title="Host-defined Objects">D.3 Host-defined Objects</a></li><li><a href="host-layering-points.html#sec-host-running-jobs" title="Running Jobs">D.4 Running Jobs</a></li><li><a href="host-layering-points.html#sec-host-internal-methods-of-exotic-objects" title="Internal Methods of Exotic Objects">D.5 Internal Methods of Exotic Objects</a></li><li><a href="host-layering-points.html#sec-host-built-in-objects-and-methods" title="Built-in Objects and Methods">D.6 Built-in Objects and Methods</a></li></ol></li><li><a href="corrections-and-clarifications-in-ecmascript-2015-with-possible-compatibility-impact.html#sec-corrections-and-clarifications-in-ecmascript-2015-with-possible-compatibility-impact" title="Corrections and Clarifications in ECMAScript 2015 with Possible Compatibility Impact">E Corrections and Clarifications in ECMAScript 2015 with Possible Compatibility Impact</a></li><li><a href="additions-and-changes-that-introduce-incompatibilities-with-prior-editions.html#sec-additions-and-changes-that-introduce-incompatibilities-with-prior-editions" title="Additions and Changes That Introduce Incompatibilities with Prior Editions">F Additions and Changes That Introduce Incompatibilities with Prior Editions</a></li><li><a href="colophon.html#sec-colophon" title="Colophon">G Colophon</a></li><li><a href="bibliography.html#sec-bibliography" title="Bibliography">H Bibliography</a></li><li><a href="copyright-and-software-license.html#sec-copyright-and-software-license" title="Copyright & Software License">I Copyright & Software License</a></li></ol></div></div> <div id="menu-spacer" class="menu-spacer"></div> <div id="menu-toggle"><svg xmlns="http://www.w3.org/2000/svg" style="width:100%; height:100%; stroke:currentColor" viewBox="0 0 120 120" width="54" height="54"> <title>Menu</title> <path stroke-width="10" stroke-linecap="round" d="M30,60 h60 M30,30 m0,5 h60 M30,90 m0,-5 h60"></path> </svg></div> <div id="shortcuts-help"> <ul> <li>Toggle shortcuts help<code>?</code></li> <li>Toggle "can call user code" annotations<code>u</code></li> <li>Navigate to/from multipage<code>m</code></li> <li>Jump to search box<code>/</code></li> <li>Toggle pinning of the current clause<code>p</code></li> <li>Jump to nth pin<code>1-9</code></li> </ul></div><div id='spec-container'><emu-clause id="sec-ecmascript-language-statements-and-declarations"> <h1>14 ECMAScript Language: Statements and Declarations</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="Statement" params="Yield, Await, Return" id="prod-Statement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ktzsppzs" id="prod-c1cDILr5"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20252"><a href="ecmascript-language-statements-and-declarations.html#prod-BlockStatement">BlockStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="xumq1cs6" id="prod-PfH00D1w"> <emu-nt params="?Yield, ?Await" id="_ref_20253"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableStatement">VariableStatement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="cziqu-45" id="prod-YqiTL09y"> <emu-nt id="_ref_20254"><a href="ecmascript-language-statements-and-declarations.html#prod-EmptyStatement">EmptyStatement</a></emu-nt> </emu-rhs> <emu-rhs a="vt4s4xgg" id="prod-WCz7iwtm"> <emu-nt params="?Yield, ?Await" id="_ref_20255"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="vpvr9yr3" id="prod-jug3e433"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20256"><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="3kwmhgcn"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20257"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="klxmhdlm" id="prod-Ro8XgDsH"> <emu-nt params="?Yield, ?Await" id="_ref_20258"><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="vtt-myod" id="prod-Rrel7YUC"> <emu-nt params="?Yield, ?Await" id="_ref_20259"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="1sriw0nt" constraints="+Return" id="prod-twdIgE_o"><emu-constraints>[+Return]</emu-constraints> <emu-nt params="?Yield, ?Await" id="_ref_20260"><a href="ecmascript-language-statements-and-declarations.html#prod-ReturnStatement">ReturnStatement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="_gejjak9" id="prod-xepAqppR"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20261"><a href="ecmascript-language-statements-and-declarations.html#prod-WithStatement">WithStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="90_gq6ig"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20262"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="ukgcnqlt" id="prod-GHPcIp4f"> <emu-nt params="?Yield, ?Await" id="_ref_20263"><a href="ecmascript-language-statements-and-declarations.html#prod-ThrowStatement">ThrowStatement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="z7s8kfe1" id="prod-HB_2xdti"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20264"><a href="ecmascript-language-statements-and-declarations.html#prod-TryStatement">TryStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="iseu28qi" id="prod-bDeNjo3k"> <emu-nt id="_ref_20265"><a href="ecmascript-language-statements-and-declarations.html#prod-DebuggerStatement">DebuggerStatement</a></emu-nt> </emu-rhs> </emu-production> <emu-production name="Declaration" params="Yield, Await" id="prod-Declaration"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-Declaration">Declaration</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="i6hr6ytb"> <emu-nt params="?Yield, ?Await, ~Default" id="_ref_20266"><a href="ecmascript-language-statements-and-declarations.html#prod-HoistableDeclaration">HoistableDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ~Default]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="jfshu5d-" id="prod-o4HYrPz3"> <emu-nt params="?Yield, ?Await, ~Default" id="_ref_20267"><a href="ecmascript-language-functions-and-classes.html#prod-ClassDeclaration">ClassDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ~Default]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="dl5lsw3w" id="prod-9H9FGeT7"> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20268"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="HoistableDeclaration" params="Yield, Await, Default" id="prod-HoistableDeclaration"> <emu-nt params="Yield, Await, Default"><a href="ecmascript-language-statements-and-declarations.html#prod-HoistableDeclaration">HoistableDeclaration</a><emu-mods><emu-params>[Yield, Await, Default]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="pm1iqgpt" id="prod-xo77HsL9"> <emu-nt params="?Yield, ?Await, ?Default" id="_ref_20269"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ?Default]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="rhqaxmir" id="prod-dpslEYBS"> <emu-nt params="?Yield, ?Await, ?Default" id="_ref_20270"><a href="ecmascript-language-functions-and-classes.html#prod-GeneratorDeclaration">GeneratorDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ?Default]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="3nfjki-g" id="prod-InkDjQLb"> <emu-nt params="?Yield, ?Await, ?Default" id="_ref_20271"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncFunctionDeclaration">AsyncFunctionDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ?Default]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="e-_qp6dd" id="prod-OBGQy9cZ"> <emu-nt params="?Yield, ?Await, ?Default" id="_ref_20272"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncGeneratorDeclaration">AsyncGeneratorDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ?Default]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BreakableStatement" params="Yield, Await, Return" id="prod-BreakableStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="olmcy7ih" id="prod-IZrgrSFg"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20273"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="uzjzv-di" id="prod-r35GfF0W"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20274"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-statement-semantics"> <h1>14.1 Statement Semantics</h1> <emu-clause id="sec-statement-semantics-runtime-semantics-evaluation" type="sdo"> <h1>14.1.1 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="HoistableDeclaration"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-HoistableDeclaration">HoistableDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="r3zmbc2x" id="prod-F2xRdnbO"> <emu-nt id="_ref_20275"><a href="ecmascript-language-functions-and-classes.html#prod-GeneratorDeclaration">GeneratorDeclaration</a></emu-nt> </emu-rhs> <emu-rhs a="xi-jap6o" id="prod-19_kIcSj"> <emu-nt id="_ref_20276"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncFunctionDeclaration">AsyncFunctionDeclaration</a></emu-nt> </emu-rhs> <emu-rhs a="n353p_mm" id="prod-AdaKcE7P"> <emu-nt id="_ref_20277"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncGeneratorDeclaration">AsyncGeneratorDeclaration</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="HoistableDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-HoistableDeclaration">HoistableDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="-nqupnlb" id="prod-80Y3L4PZ"><emu-nt id="_ref_20278"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="Evaluation" id="_ref_6679"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20279"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt>.</li></ol></emu-alg> <emu-grammar><emu-production name="BreakableStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="kmxl4yum" id="prod-FFjrmEWz"> <emu-nt id="_ref_20280"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> </emu-rhs> <emu-rhs a="nuio-xfp" id="prod-cXJGjZtb"> <emu-nt id="_ref_20281"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>newLabelSet</var> be a new empty <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6680"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref>.</li><li>Return ? <emu-xref aoid="LabelledEvaluation" id="_ref_6681"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-labelledevaluation" class="e-user-code">LabelledEvaluation</a></emu-xref> of this <emu-nt id="_ref_20282"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a></emu-nt> with argument <var>newLabelSet</var>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-block"> <h1>14.2 Block</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="BlockStatement" params="Yield, Await, Return" id="prod-BlockStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-BlockStatement">BlockStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="zwpfwt4j"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20283"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="Block" params="Yield, Await, Return" id="prod-Block"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uij9rcu7" id="prod-30nvN6ck"> <emu-t>{</emu-t> <emu-nt params="?Yield, ?Await, ?Return" optional="" id="_ref_20284"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> <emu-production name="StatementList" params="Yield, Await, Return" id="prod-StatementList"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="owubwn_s"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20285"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementListItem">StatementListItem</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="21clqs0p" id="prod--OFVjnjw"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20286"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20287"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementListItem">StatementListItem</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="StatementListItem" params="Yield, Await, Return" id="prod-StatementListItem"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementListItem">StatementListItem</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="septp5sa" id="prod-GHY4Vd3_"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20288"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="mtktetk8" id="prod-yYByJL6Z"> <emu-nt params="?Yield, ?Await" id="_ref_20289"><a href="ecmascript-language-statements-and-declarations.html#prod-Declaration">Declaration</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-block-static-semantics-early-errors"> <h1>14.2.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="Block" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="z4ljp0ar"> <emu-t>{</emu-t> <emu-nt id="_ref_20290"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if the <emu-xref aoid="LexicallyDeclaredNames" id="_ref_6682"><a href="syntax-directed-operations.html#sec-static-semantics-lexicallydeclarednames">LexicallyDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20291"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> contains any duplicate entries. </li> <li> It is a Syntax Error if any element of the <emu-xref aoid="LexicallyDeclaredNames" id="_ref_6683"><a href="syntax-directed-operations.html#sec-static-semantics-lexicallydeclarednames">LexicallyDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20292"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> also occurs in the <emu-xref aoid="VarDeclaredNames" id="_ref_6684"><a href="syntax-directed-operations.html#sec-static-semantics-vardeclarednames">VarDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20293"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>. </li> </ul> </emu-clause> <emu-clause id="sec-block-runtime-semantics-evaluation" type="sdo"> <h1>14.2.2 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="Block" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gbpaspne" id="prod-GN03td2O"> <emu-t>{</emu-t> <emu-t>}</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="Block" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="z4ljp0ar" id="prod-CUMWT9xI"> <emu-t>{</emu-t> <emu-nt id="_ref_20294"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_6685"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>blockEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_6686"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>oldEnv</var>).</li><li>Perform <emu-xref aoid="BlockDeclarationInstantiation" id="_ref_6687"><a href="ecmascript-language-statements-and-declarations.html#sec-blockdeclarationinstantiation">BlockDeclarationInstantiation</a></emu-xref>(<emu-nt id="_ref_20295"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>, <var>blockEnv</var>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6688"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>blockEnv</var>.</li><li>Let <var>blockValue</var> be <emu-xref aoid="Completion" id="_ref_6689"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6690"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20296"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6691"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return ? <var>blockValue</var>.</li></ol></emu-alg> <emu-note>Note 1<div class="note-contents"> No matter how control leaves the <emu-nt id="_ref_20297"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> the LexicalEnvironment is always restored to its former state. </div></emu-note> <emu-grammar><emu-production name="StatementList" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="dbrzeh7l" id="prod-qY9k7-Mq"> <emu-nt id="_ref_20298"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> <emu-nt id="_ref_20299"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementListItem">StatementListItem</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>sl</var> be ? <emu-xref aoid="Evaluation" id="_ref_6692"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20300"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>.</li><li>Let <var>s</var> be <emu-xref aoid="Completion" id="_ref_6693"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6694"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20301"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementListItem">StatementListItem</a></emu-nt>).</li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_6695"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>s</var>, <var>sl</var>).</li></ol></emu-alg> <emu-note>Note 2<div class="note-contents"> The value of a <emu-nt id="_ref_20302"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> is the value of the last value-producing item in the <emu-nt id="_ref_20303"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>. For example, the following calls to the <code>eval</code> function all return the value 1: <pre><code class="javascript hljs">eval("1;;;;;") eval("1;{}") eval("1;var a;")</code></pre> </div></emu-note> </emu-clause> <emu-clause id="sec-blockdeclarationinstantiation" type="abstract operation" aoid="BlockDeclarationInstantiation"> <h1>14.2.3 BlockDeclarationInstantiation ( <var>code</var>, <var>env</var> )</h1> The abstract operation BlockDeclarationInstantiation takes arguments <var>code</var> (a <emu-xref href="#sec-syntactic-grammar" id="_ref_6696"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>) and <var>env</var> (a <emu-xref href="#sec-declarative-environment-records" id="_ref_6697"><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records">Declarative Environment Record</a></emu-xref>) and returns <emu-const>unused</emu-const>. <var>code</var> is the <emu-xref href="#sec-syntactic-grammar" id="_ref_6698"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref> corresponding to the body of the block. <var>env</var> is the <emu-xref href="#sec-environment-records" id="_ref_6699"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> in which bindings are to be created. <emu-note>Note<div class="note-contents"> When a <emu-nt id="_ref_20304"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> or <emu-nt id="_ref_20305"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> is evaluated a new <emu-xref href="#sec-declarative-environment-records" id="_ref_6700"><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records">Declarative Environment Record</a></emu-xref> is created and bindings for each block scoped variable, constant, function, or class declared in the block are instantiated in the <emu-xref href="#sec-environment-records" id="_ref_6701"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref>. </div></emu-note> It performs the following steps when called:  <emu-alg><ol><li>Let <var>declarations</var> be the <emu-xref aoid="LexicallyScopedDeclarations" id="_ref_6702"><a href="syntax-directed-operations.html#sec-static-semantics-lexicallyscopeddeclarations">LexicallyScopedDeclarations</a></emu-xref> of <var>code</var>.</li><li>Let <var>privateEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_6703"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s PrivateEnvironment.</li><li>For each element <var>d</var> of <var>declarations</var>, do<ol><li>For each element <var>dn</var> of the <emu-xref aoid="BoundNames" id="_ref_6704"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <var>d</var>, do<ol><li>If <emu-xref aoid="IsConstantDeclaration" id="_ref_6705"><a href="syntax-directed-operations.html#sec-static-semantics-isconstantdeclaration">IsConstantDeclaration</a></emu-xref> of <var>d</var> is <emu-val>true</emu-val>, then<ol><li>Perform ! <var>env</var>.CreateImmutableBinding(<var>dn</var>, <emu-val>true</emu-val>).</li></ol></li><li>Else,<ol><li id="step-blockdeclarationinstantiation-createmutablebinding">Perform ! <var>env</var>.CreateMutableBinding(<var>dn</var>, <emu-val>false</emu-val>). NOTE: This step is replaced in section <emu-xref href="#sec-web-compat-blockdeclarationinstantiation" id="_ref_439"><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-blockdeclarationinstantiation">B.3.2.6</a></emu-xref>.</li></ol></li></ol></li><li>If <var>d</var> is either a <emu-nt id="_ref_20306"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt>, a <emu-nt id="_ref_20307"><a href="ecmascript-language-functions-and-classes.html#prod-GeneratorDeclaration">GeneratorDeclaration</a></emu-nt>, an <emu-nt id="_ref_20308"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncFunctionDeclaration">AsyncFunctionDeclaration</a></emu-nt>, or an <emu-nt id="_ref_20309"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncGeneratorDeclaration">AsyncGeneratorDeclaration</a></emu-nt>, then<ol><li>Let <var>fn</var> be the sole element of the <emu-xref aoid="BoundNames" id="_ref_6706"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <var>d</var>.</li><li>Let <var>fo</var> be <emu-xref aoid="InstantiateFunctionObject" id="_ref_6707"><a href="syntax-directed-operations.html#sec-runtime-semantics-instantiatefunctionobject">InstantiateFunctionObject</a></emu-xref> of <var>d</var> with arguments <var>env</var> and <var>privateEnv</var>.</li><li id="step-blockdeclarationinstantiation-initializebinding">Perform ! <var>env</var>.InitializeBinding(<var>fn</var>, <var>fo</var>). NOTE: This step is replaced in section <emu-xref href="#sec-web-compat-blockdeclarationinstantiation" id="_ref_440"><a href="additional-ecmascript-features-for-web-browsers.html#sec-web-compat-blockdeclarationinstantiation">B.3.2.6</a></emu-xref>.</li></ol></li></ol></li><li>Return <emu-const>unused</emu-const>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-declarations-and-the-variable-statement"> <h1>14.3 Declarations and the Variable Statement</h1> <emu-clause id="sec-let-and-const-declarations"> <h1>14.3.1 Let and Const Declarations</h1> <emu-note>Note<div class="note-contents"> <code>let</code> and <code>const</code> declarations define variables that are scoped to the <emu-xref href="#running-execution-context" id="_ref_6708"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment. The variables are created when their containing <emu-xref href="#sec-environment-records" id="_ref_6709"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> is instantiated but may not be accessed in any way until the variable's <emu-nt id="_ref_20310"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> is evaluated. A variable defined by a <emu-nt id="_ref_20311"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> with an <emu-nt id="_ref_20312"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> is assigned the value of its <emu-nt id="_ref_20313"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>'s <emu-nt id="_ref_20314"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> when the <emu-nt id="_ref_20315"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> is evaluated, not when the variable is created. If a <emu-nt id="_ref_20316"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> in a <code>let</code> declaration does not have an <emu-nt id="_ref_20317"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> the variable is assigned the value <emu-val>undefined</emu-val> when the <emu-nt id="_ref_20318"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> is evaluated. </div></emu-note> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="LexicalDeclaration" params="In, Yield, Await" id="prod-LexicalDeclaration"> <emu-nt params="In, Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a><emu-mods><emu-params>[In, Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jsmbgalx" id="prod-10DUWE8d"> <emu-nt id="_ref_20319"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20320"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> <emu-production name="LetOrConst" id="prod-LetOrConst"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="laxrvawy" id="prod-7oqY0VPN"> <emu-t>let</emu-t> </emu-rhs> <emu-rhs a="nim_d4hb" id="prod-rTRI6GVQ"> <emu-t>const</emu-t> </emu-rhs> </emu-production> <emu-production name="BindingList" params="In, Yield, Await" id="prod-BindingList"> <emu-nt params="In, Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a><emu-mods><emu-params>[In, Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ned6hkwu"> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20321"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="fdx7nvya" id="prod-FYQ2Ly4e"> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20322"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>,</emu-t> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20323"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="LexicalBinding" params="In, Yield, Await" id="prod-LexicalBinding"> <emu-nt params="In, Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a><emu-mods><emu-params>[In, Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jut8etgz" id="prod-l3Hg2UJ0"> <emu-nt params="?Yield, ?Await" id="_ref_20324"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="?In, ?Yield, ?Await" optional="" id="_ref_20325"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="sdckvxer" id="prod-FppJpMK8"> <emu-nt params="?Yield, ?Await" id="_ref_20326"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20327"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-let-and-const-declarations-static-semantics-early-errors"> <h1>14.3.1.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="LexicalDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="deqecbrp"> <emu-nt id="_ref_20328"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt id="_ref_20329"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if the <emu-xref aoid="BoundNames" id="_ref_6710"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20330"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt> contains <emu-val>"let"</emu-val>. </li> <li> It is a Syntax Error if the <emu-xref aoid="BoundNames" id="_ref_6711"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20331"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt> contains any duplicate entries. </li> </ul> <emu-grammar><emu-production name="LexicalBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="c5neqctp"> <emu-nt id="_ref_20332"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> <emu-nt optional="" id="_ref_20333"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-nt id="_ref_20334"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> is not present and <emu-xref aoid="IsConstantDeclaration" id="_ref_6712"><a href="syntax-directed-operations.html#sec-static-semantics-isconstantdeclaration">IsConstantDeclaration</a></emu-xref> of the <emu-nt id="_ref_20335"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> containing this <emu-nt id="_ref_20336"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> is <emu-val>true</emu-val>. </li> </ul> </emu-clause> <emu-clause id="sec-let-and-const-declarations-runtime-semantics-evaluation" type="sdo"> <h1>14.3.1.2 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="LexicalDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="deqecbrp" id="prod-dx4AGe8K"> <emu-nt id="_ref_20337"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt id="_ref_20338"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Perform ? <emu-xref aoid="Evaluation" id="_ref_6713"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20339"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt>.</li><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="BindingList" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="dt40zeyt" id="prod-EyFo2V-D"> <emu-nt id="_ref_20340"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt> <emu-t>,</emu-t> <emu-nt id="_ref_20341"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Perform ? <emu-xref aoid="Evaluation" id="_ref_6714"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20342"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingList">BindingList</a></emu-nt>.</li><li>Return ? <emu-xref aoid="Evaluation" id="_ref_6715"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20343"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt>.</li></ol></emu-alg> <emu-grammar><emu-production name="LexicalBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uolyom43" id="prod-mW_TWZBz"><emu-nt id="_ref_20344"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>lhs</var> be ! <emu-xref aoid="ResolveBinding" id="_ref_6716"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding">ResolveBinding</a></emu-xref>(<emu-xref aoid="StringValue" id="_ref_6717"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20345"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt>).</li><li>Perform ! <emu-xref aoid="InitializeReferencedBinding" id="_ref_6718"><a href="ecmascript-data-types-and-values.html#sec-initializereferencedbinding">InitializeReferencedBinding</a></emu-xref>(<var>lhs</var>, <emu-val>undefined</emu-val>).</li><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> A <emu-xref href="#sec-static-semantic-rules" id="_ref_6719"><a href="notational-conventions.html#sec-static-semantic-rules">static semantics</a></emu-xref> rule ensures that this form of <emu-nt id="_ref_20346"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> never occurs in a <code>const</code> declaration. </div></emu-note> <emu-grammar><emu-production name="LexicalBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ib7lg1vi" id="prod-gOqjOKq_"> <emu-nt id="_ref_20347"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> <emu-nt id="_ref_20348"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>bindingId</var> be the <emu-xref aoid="StringValue" id="_ref_6720"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20349"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt>.</li><li>Let <var>lhs</var> be ! <emu-xref aoid="ResolveBinding" id="_ref_6721"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding">ResolveBinding</a></emu-xref>(<var>bindingId</var>).</li><li>If <emu-xref aoid="IsAnonymousFunctionDefinition" id="_ref_6722"><a href="syntax-directed-operations.html#sec-isanonymousfunctiondefinition">IsAnonymousFunctionDefinition</a></emu-xref>(<emu-nt id="_ref_20350"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>) is <emu-val>true</emu-val>, then<ol><li>Let <var>value</var> be ? <emu-xref aoid="NamedEvaluation" id="_ref_6723"><a href="syntax-directed-operations.html#sec-runtime-semantics-namedevaluation" class="e-user-code">NamedEvaluation</a></emu-xref> of <emu-nt id="_ref_20351"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> with argument <var>bindingId</var>.</li></ol></li><li>Else,<ol><li>Let <var>rhs</var> be ? <emu-xref aoid="Evaluation" id="_ref_6724"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20352"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>.</li><li>Let <var>value</var> be ? <emu-xref aoid="GetValue" id="_ref_6725"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>rhs</var>).</li></ol></li><li>Perform ! <emu-xref aoid="InitializeReferencedBinding" id="_ref_6726"><a href="ecmascript-data-types-and-values.html#sec-initializereferencedbinding">InitializeReferencedBinding</a></emu-xref>(<var>lhs</var>, <var>value</var>).</li><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="LexicalBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="dd1t5ekf" id="prod-HJPtX-Q7"> <emu-nt id="_ref_20353"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt> <emu-nt id="_ref_20354"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>rhs</var> be ? <emu-xref aoid="Evaluation" id="_ref_6727"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20355"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>.</li><li>Let <var>value</var> be ? <emu-xref aoid="GetValue" id="_ref_6728"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>rhs</var>).</li><li>Let <var>env</var> be the <emu-xref href="#running-execution-context" id="_ref_6729"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Return ? <emu-xref aoid="BindingInitialization" id="_ref_6730"><a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" class="e-user-code">BindingInitialization</a></emu-xref> of <emu-nt id="_ref_20356"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt> with arguments <var>value</var> and <var>env</var>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-variable-statement"> <h1>14.3.2 Variable Statement</h1> <emu-note>Note<div class="note-contents"> A <code>var</code> statement declares variables that are scoped to the <emu-xref href="#running-execution-context" id="_ref_6731"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s VariableEnvironment. Var variables are created when their containing <emu-xref href="#sec-environment-records" id="_ref_6732"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> is instantiated and are initialized to <emu-val>undefined</emu-val> when created. Within the scope of any VariableEnvironment a common <emu-nt id="_ref_20357"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> may appear in more than one <emu-nt id="_ref_20358"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> but those declarations collectively define only one variable. A variable defined by a <emu-nt id="_ref_20359"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> with an <emu-nt id="_ref_20360"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> is assigned the value of its <emu-nt id="_ref_20361"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>'s <emu-nt id="_ref_20362"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> when the <emu-nt id="_ref_20363"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> is executed, not when the variable is created. </div></emu-note> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="VariableStatement" params="Yield, Await" id="prod-VariableStatement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableStatement">VariableStatement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="tbwjaldb" id="prod-03w8p9mr"> <emu-t>var</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20364"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> <emu-production name="VariableDeclarationList" params="In, Yield, Await" id="prod-VariableDeclarationList"> <emu-nt params="In, Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a><emu-mods><emu-params>[In, Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ps4sw3ys" id="prod-bXRN6REu"> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20365"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="xsh3skws" id="prod-kqbqpKlK"> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20366"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>,</emu-t> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20367"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="VariableDeclaration" params="In, Yield, Await" id="prod-VariableDeclaration"> <emu-nt params="In, Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a><emu-mods><emu-params>[In, Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jut8etgz" id="prod-IeHby7A3"> <emu-nt params="?Yield, ?Await" id="_ref_20368"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="?In, ?Yield, ?Await" optional="" id="_ref_20369"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="sdckvxer" id="prod-MhsdViui"> <emu-nt params="?Yield, ?Await" id="_ref_20370"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="?In, ?Yield, ?Await" id="_ref_20371"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-params>[?In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-variable-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.3.2.1 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="VariableStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-VariableStatement">VariableStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="m0ehvb8m" id="prod-3b9-3HdT"> <emu-t>var</emu-t> <emu-nt id="_ref_20372"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Perform ? <emu-xref aoid="Evaluation" id="_ref_6733"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20373"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt>.</li><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="VariableDeclarationList" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="oavweevb" id="prod-mRNvbUb_"> <emu-nt id="_ref_20374"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt> <emu-t>,</emu-t> <emu-nt id="_ref_20375"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Perform ? <emu-xref aoid="Evaluation" id="_ref_6734"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20376"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt>.</li><li>Return ? <emu-xref aoid="Evaluation" id="_ref_6735"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20377"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt>.</li></ol></emu-alg> <emu-grammar><emu-production name="VariableDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uolyom43" id="prod-DloKhDSp"><emu-nt id="_ref_20378"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="VariableDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ib7lg1vi" id="prod-luUzRvcA"> <emu-nt id="_ref_20379"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> <emu-nt id="_ref_20380"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>bindingId</var> be the <emu-xref aoid="StringValue" id="_ref_6736"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20381"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt>.</li><li>Let <var>lhs</var> be ? <emu-xref aoid="ResolveBinding" id="_ref_6737"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding" class="e-user-code">ResolveBinding</a></emu-xref>(<var>bindingId</var>).</li><li>If <emu-xref aoid="IsAnonymousFunctionDefinition" id="_ref_6738"><a href="syntax-directed-operations.html#sec-isanonymousfunctiondefinition">IsAnonymousFunctionDefinition</a></emu-xref>(<emu-nt id="_ref_20382"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>) is <emu-val>true</emu-val>, then<ol><li>Let <var>value</var> be ? <emu-xref aoid="NamedEvaluation" id="_ref_6739"><a href="syntax-directed-operations.html#sec-runtime-semantics-namedevaluation" class="e-user-code">NamedEvaluation</a></emu-xref> of <emu-nt id="_ref_20383"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> with argument <var>bindingId</var>.</li></ol></li><li>Else,<ol><li>Let <var>rhs</var> be ? <emu-xref aoid="Evaluation" id="_ref_6740"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20384"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>.</li><li>Let <var>value</var> be ? <emu-xref aoid="GetValue" id="_ref_6741"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>rhs</var>).</li></ol></li><li id="step-vardecllist-evaluation-putvalue">Perform ? <emu-xref aoid="PutValue" id="_ref_6742"><a href="ecmascript-data-types-and-values.html#sec-putvalue" class="e-user-code">PutValue</a></emu-xref>(<var>lhs</var>, <var>value</var>).</li><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> If a <emu-nt id="_ref_20385"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> is nested within a with statement and the <emu-nt id="_ref_20386"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> in the <emu-nt id="_ref_20387"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> is the same as a <emu-xref href="#property-name" id="_ref_6743"><a href="ecmascript-data-types-and-values.html#property-name">property name</a></emu-xref> of the binding object of the with statement's <emu-xref href="#sec-object-environment-records" id="_ref_6744"><a href="executable-code-and-execution-contexts.html#sec-object-environment-records">Object Environment Record</a></emu-xref>, then step <emu-xref href="#step-vardecllist-evaluation-putvalue" id="_ref_441"><a href="ecmascript-language-statements-and-declarations.html#step-vardecllist-evaluation-putvalue">5</a></emu-xref> will assign <var>value</var> to the property instead of assigning to the VariableEnvironment binding of the <emu-nt id="_ref_20388"><a href="ecmascript-language-expressions.html#prod-Identifier">Identifier</a></emu-nt>. </div></emu-note> <emu-grammar><emu-production name="VariableDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclaration">VariableDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="dd1t5ekf" id="prod-615TDHeB"> <emu-nt id="_ref_20389"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt> <emu-nt id="_ref_20390"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>rhs</var> be ? <emu-xref aoid="Evaluation" id="_ref_6745"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20391"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>.</li><li>Let <var>rVal</var> be ? <emu-xref aoid="GetValue" id="_ref_6746"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>rhs</var>).</li><li>Return ? <emu-xref aoid="BindingInitialization" id="_ref_6747"><a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" class="e-user-code">BindingInitialization</a></emu-xref> of <emu-nt id="_ref_20392"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt> with arguments <var>rVal</var> and <emu-val>undefined</emu-val>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-destructuring-binding-patterns"> <h1>14.3.3 Destructuring Binding Patterns</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="BindingPattern" params="Yield, Await" id="prod-BindingPattern"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="fwd2jmee" id="prod-5GwwFymY"> <emu-nt params="?Yield, ?Await" id="_ref_20393"><a href="ecmascript-language-statements-and-declarations.html#prod-ObjectBindingPattern">ObjectBindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="hpyn1kot" id="prod-nQ2ZFnUa"> <emu-nt params="?Yield, ?Await" id="_ref_20394"><a href="ecmascript-language-statements-and-declarations.html#prod-ArrayBindingPattern">ArrayBindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="ObjectBindingPattern" params="Yield, Await" id="prod-ObjectBindingPattern"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ObjectBindingPattern">ObjectBindingPattern</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gbpaspne" id="prod-Zq1KBCx2"> <emu-t>{</emu-t> <emu-t>}</emu-t> </emu-rhs> <emu-rhs a="u51ece_j" id="prod-5lmgiaFr"> <emu-t>{</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20395"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestProperty">BindingRestProperty</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> <emu-rhs a="sd_sxlxl" id="prod-xrMoI6uo"> <emu-t>{</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20396"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> <emu-rhs a="98sthfnw" id="prod-ZImPf3XQ"> <emu-t>{</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20397"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>,</emu-t> <emu-nt params="?Yield, ?Await" optional="" id="_ref_20398"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestProperty">BindingRestProperty</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> <emu-production name="ArrayBindingPattern" params="Yield, Await" id="prod-ArrayBindingPattern"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ArrayBindingPattern">ArrayBindingPattern</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="82yazf9m" id="prod-GTLtfjt0"> <emu-t>[</emu-t> <emu-nt optional="" id="_ref_20399"><a href="ecmascript-language-expressions.html#prod-Elision">Elision</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await" optional="" id="_ref_20400"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestElement">BindingRestElement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>]</emu-t> </emu-rhs> <emu-rhs a="tz2jlcig"> <emu-t>[</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20401"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElementList">BindingElementList</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>]</emu-t> </emu-rhs> <emu-rhs a="ezfh7oge" id="prod-ZEEMEcAo"> <emu-t>[</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20402"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElementList">BindingElementList</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>,</emu-t> <emu-nt optional="" id="_ref_20403"><a href="ecmascript-language-expressions.html#prod-Elision">Elision</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await" optional="" id="_ref_20404"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestElement">BindingRestElement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>]</emu-t> </emu-rhs> </emu-production> <emu-production name="BindingRestProperty" params="Yield, Await" id="prod-BindingRestProperty"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestProperty">BindingRestProperty</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="nldxez3v" id="prod-ltwW708a"> <emu-t>...</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20405"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BindingPropertyList" params="Yield, Await" id="prod-BindingPropertyList"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="8baidhkc"> <emu-nt params="?Yield, ?Await" id="_ref_20406"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="ewlfehxq" id="prod-TkJ_upuv"> <emu-nt params="?Yield, ?Await" id="_ref_20407"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>,</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20408"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BindingElementList" params="Yield, Await" id="prod-BindingElementList"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElementList">BindingElementList</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="lpaw4nny"> <emu-nt params="?Yield, ?Await" id="_ref_20409"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElisionElement">BindingElisionElement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="5z8zw101" id="prod-QAGJVJ9v"> <emu-nt params="?Yield, ?Await" id="_ref_20410"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElementList">BindingElementList</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>,</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20411"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElisionElement">BindingElisionElement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BindingElisionElement" params="Yield, Await" id="prod-BindingElisionElement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElisionElement">BindingElisionElement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="5jbcqvdg" id="prod-eAKFkNTn"> <emu-nt optional="" id="_ref_20412"><a href="ecmascript-language-expressions.html#prod-Elision">Elision</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await" id="_ref_20413"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElement">BindingElement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BindingProperty" params="Yield, Await" id="prod-BindingProperty"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="01jnavb_" id="prod-P9s8hLuP"> <emu-nt params="?Yield, ?Await" id="_ref_20414"><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="xcksc8qh" id="prod-VmvTFDAY"> <emu-nt params="?Yield, ?Await" id="_ref_20415"><a href="ecmascript-language-expressions.html#prod-PropertyName">PropertyName</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>:</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20416"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElement">BindingElement</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BindingElement" params="Yield, Await" id="prod-BindingElement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElement">BindingElement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="01jnavb_"> <emu-nt params="?Yield, ?Await" id="_ref_20417"><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="eyv5t9mz" id="prod-qY39_uPQ"> <emu-nt params="?Yield, ?Await" id="_ref_20418"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20419"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="SingleNameBinding" params="Yield, Await" id="prod-SingleNameBinding"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="mg7mmvow" id="prod-8lbkfoVZ"> <emu-nt params="?Yield, ?Await" id="_ref_20420"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20421"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="BindingRestElement" params="Yield, Await" id="prod-BindingRestElement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestElement">BindingRestElement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="nldxez3v" id="prod-0fOwNHr-"> <emu-t>...</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20422"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="lb7grnzq" id="prod-iBHkClE5"> <emu-t>...</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20423"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-destructuring-binding-patterns-runtime-semantics-propertybindinginitialization" type="sdo" aoid="PropertyBindingInitialization"> <h1>14.3.3.1 Runtime Semantics: PropertyBindingInitialization</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6748"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> PropertyBindingInitialization takes arguments <var>value</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6749"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and <var>environment</var> (an <emu-xref href="#sec-environment-records" id="_ref_6750"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> or <emu-val>undefined</emu-val>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6751"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6752"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of <emu-xref href="#sec-object-type" id="_ref_6753"><a href="ecmascript-data-types-and-values.html#sec-object-type">property keys</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6754"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It collects a list of all bound property names. It is defined piecewise over the following productions: <emu-grammar><emu-production name="BindingPropertyList" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="bzdeo9zt" id="prod-jhtKd-Y5"> <emu-nt id="_ref_20424"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a></emu-nt> <emu-t>,</emu-t> <emu-nt id="_ref_20425"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>boundNames</var> be ? <emu-xref aoid="PropertyBindingInitialization" id="_ref_6755"><a href="ecmascript-language-statements-and-declarations.html#sec-destructuring-binding-patterns-runtime-semantics-propertybindinginitialization" class="e-user-code">PropertyBindingInitialization</a></emu-xref> of <emu-nt id="_ref_20426"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPropertyList">BindingPropertyList</a></emu-nt> with arguments <var>value</var> and <var>environment</var>.</li><li>Let <var>nextNames</var> be ? <emu-xref aoid="PropertyBindingInitialization" id="_ref_6756"><a href="ecmascript-language-statements-and-declarations.html#sec-destructuring-binding-patterns-runtime-semantics-propertybindinginitialization" class="e-user-code">PropertyBindingInitialization</a></emu-xref> of <emu-nt id="_ref_20427"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a></emu-nt> with arguments <var>value</var> and <var>environment</var>.</li><li>Return the <emu-xref href="#list-concatenation" id="_ref_6757"><a href="ecmascript-data-types-and-values.html#list-concatenation">list-concatenation</a></emu-xref> of <var>boundNames</var> and <var>nextNames</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="BindingProperty" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="lof8ala-" id="prod--5EhKk0m"><emu-nt id="_ref_20428"><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>name</var> be the sole element of the <emu-xref aoid="BoundNames" id="_ref_6758"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20429"><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a></emu-nt>.</li><li>Perform ? <emu-xref aoid="KeyedBindingInitialization" id="_ref_6759"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-keyedbindinginitialization" class="e-user-code">KeyedBindingInitialization</a></emu-xref> of <emu-nt id="_ref_20430"><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a></emu-nt> with arguments <var>value</var>, <var>environment</var>, and <var>name</var>.</li><li>Return « <var>name</var> ».</li></ol></emu-alg> <emu-grammar><emu-production name="BindingProperty" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BindingProperty">BindingProperty</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="mhvrwluk" id="prod-1euONYQ-"> <emu-nt id="_ref_20431"><a href="ecmascript-language-expressions.html#prod-PropertyName">PropertyName</a></emu-nt> <emu-t>:</emu-t> <emu-nt id="_ref_20432"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElement">BindingElement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>P</var> be ? <emu-xref aoid="Evaluation" id="_ref_6760"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20433"><a href="ecmascript-language-expressions.html#prod-PropertyName">PropertyName</a></emu-nt>.</li><li>Perform ? <emu-xref aoid="KeyedBindingInitialization" id="_ref_6761"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-keyedbindinginitialization" class="e-user-code">KeyedBindingInitialization</a></emu-xref> of <emu-nt id="_ref_20434"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElement">BindingElement</a></emu-nt> with arguments <var>value</var>, <var>environment</var>, and <var>P</var>.</li><li>Return « <var>P</var> ».</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-destructuring-binding-patterns-runtime-semantics-restbindinginitialization" type="sdo" aoid="RestBindingInitialization"> <h1>14.3.3.2 Runtime Semantics: RestBindingInitialization</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6762"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> RestBindingInitialization takes arguments <var>value</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6763"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), <var>environment</var> (an <emu-xref href="#sec-environment-records" id="_ref_6764"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> or <emu-val>undefined</emu-val>), and <var>excludedNames</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6765"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of <emu-xref href="#sec-object-type" id="_ref_6766"><a href="ecmascript-data-types-and-values.html#sec-object-type">property keys</a></emu-xref>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6767"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> <emu-const>unused</emu-const> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6768"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="BindingRestProperty" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BindingRestProperty">BindingRestProperty</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ffhe3nqa" id="prod-jjw6mbi6"> <emu-t>...</emu-t> <emu-nt id="_ref_20435"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>lhs</var> be ? <emu-xref aoid="ResolveBinding" id="_ref_6769"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding" class="e-user-code">ResolveBinding</a></emu-xref>(<emu-xref aoid="StringValue" id="_ref_6770"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20436"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt>, <var>environment</var>).</li><li>Let <var>restObj</var> be <emu-xref aoid="OrdinaryObjectCreate" id="_ref_6771"><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryobjectcreate">OrdinaryObjectCreate</a></emu-xref>(<emu-xref href="#sec-properties-of-the-object-prototype-object" id="_ref_6772"><a href="fundamental-objects.html#sec-properties-of-the-object-prototype-object">%Object.prototype%</a></emu-xref>).</li><li>Perform ? <emu-xref aoid="CopyDataProperties" id="_ref_6773"><a href="abstract-operations.html#sec-copydataproperties" class="e-user-code">CopyDataProperties</a></emu-xref>(<var>restObj</var>, <var>value</var>, <var>excludedNames</var>).</li><li>If <var>environment</var> is <emu-val>undefined</emu-val>, return ? <emu-xref aoid="PutValue" id="_ref_6774"><a href="ecmascript-data-types-and-values.html#sec-putvalue" class="e-user-code">PutValue</a></emu-xref>(<var>lhs</var>, <var>restObj</var>).</li><li>Return ? <emu-xref aoid="InitializeReferencedBinding" id="_ref_6775"><a href="ecmascript-data-types-and-values.html#sec-initializereferencedbinding">InitializeReferencedBinding</a></emu-xref>(<var>lhs</var>, <var>restObj</var>).</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-runtime-semantics-keyedbindinginitialization" type="sdo" aoid="KeyedBindingInitialization"> <h1>14.3.3.3 Runtime Semantics: KeyedBindingInitialization</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6776"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> KeyedBindingInitialization takes arguments <var>value</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6777"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), <var>environment</var> (an <emu-xref href="#sec-environment-records" id="_ref_6778"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> or <emu-val>undefined</emu-val>), and <var>propertyName</var> (a <emu-xref href="#sec-object-type" id="_ref_6779"><a href="ecmascript-data-types-and-values.html#sec-object-type">property key</a></emu-xref>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6780"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> <emu-const>unused</emu-const> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6781"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. <emu-note>Note<div class="note-contents"> When <emu-val>undefined</emu-val> is passed for <var>environment</var> it indicates that a <emu-xref aoid="PutValue" id="_ref_6782"><a href="ecmascript-data-types-and-values.html#sec-putvalue">PutValue</a></emu-xref> operation should be used to assign the initialization value. This is the case for formal parameter lists of <emu-xref href="#non-strict-function" id="_ref_6783"><a href="ordinary-and-exotic-objects-behaviours.html#non-strict-function">non-strict functions</a></emu-xref>. In that case the formal parameter bindings are preinitialized in order to deal with the possibility of multiple parameters with the same name. </div></emu-note> It is defined piecewise over the following productions: <emu-grammar><emu-production name="BindingElement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BindingElement">BindingElement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ahx6lm0w" id="prod-kKvAd4Kx"> <emu-nt id="_ref_20437"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt> <emu-nt optional="" id="_ref_20438"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>v</var> be ? <emu-xref aoid="GetV" id="_ref_6784"><a href="abstract-operations.html#sec-getv" class="e-user-code">GetV</a></emu-xref>(<var>value</var>, <var>propertyName</var>).</li><li>If <emu-nt id="_ref_20439"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> is present and <var>v</var> is <emu-val>undefined</emu-val>, then<ol><li>Let <var>defaultValue</var> be ? <emu-xref aoid="Evaluation" id="_ref_6785"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20440"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>.</li><li>Set <var>v</var> to ? <emu-xref aoid="GetValue" id="_ref_6786"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>defaultValue</var>).</li></ol></li><li>Return ? <emu-xref aoid="BindingInitialization" id="_ref_6787"><a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" class="e-user-code">BindingInitialization</a></emu-xref> of <emu-nt id="_ref_20441"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt> with arguments <var>v</var> and <var>environment</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="SingleNameBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-SingleNameBinding">SingleNameBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="c5neqctp" id="prod-v4J727kL"> <emu-nt id="_ref_20442"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> <emu-nt optional="" id="_ref_20443"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>bindingId</var> be the <emu-xref aoid="StringValue" id="_ref_6788"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20444"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt>.</li><li>Let <var>lhs</var> be ? <emu-xref aoid="ResolveBinding" id="_ref_6789"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding" class="e-user-code">ResolveBinding</a></emu-xref>(<var>bindingId</var>, <var>environment</var>).</li><li>Let <var>v</var> be ? <emu-xref aoid="GetV" id="_ref_6790"><a href="abstract-operations.html#sec-getv" class="e-user-code">GetV</a></emu-xref>(<var>value</var>, <var>propertyName</var>).</li><li>If <emu-nt id="_ref_20445"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> is present and <var>v</var> is <emu-val>undefined</emu-val>, then<ol><li>If <emu-xref aoid="IsAnonymousFunctionDefinition" id="_ref_6791"><a href="syntax-directed-operations.html#sec-isanonymousfunctiondefinition">IsAnonymousFunctionDefinition</a></emu-xref>(<emu-nt id="_ref_20446"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>) is <emu-val>true</emu-val>, then<ol><li>Set <var>v</var> to ? <emu-xref aoid="NamedEvaluation" id="_ref_6792"><a href="syntax-directed-operations.html#sec-runtime-semantics-namedevaluation" class="e-user-code">NamedEvaluation</a></emu-xref> of <emu-nt id="_ref_20447"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt> with argument <var>bindingId</var>.</li></ol></li><li>Else,<ol><li>Let <var>defaultValue</var> be ? <emu-xref aoid="Evaluation" id="_ref_6793"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20448"><a href="ecmascript-language-expressions.html#prod-Initializer">Initializer</a></emu-nt>.</li><li>Set <var>v</var> to ? <emu-xref aoid="GetValue" id="_ref_6794"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>defaultValue</var>).</li></ol></li></ol></li><li>If <var>environment</var> is <emu-val>undefined</emu-val>, return ? <emu-xref aoid="PutValue" id="_ref_6795"><a href="ecmascript-data-types-and-values.html#sec-putvalue" class="e-user-code">PutValue</a></emu-xref>(<var>lhs</var>, <var>v</var>).</li><li>Return ? <emu-xref aoid="InitializeReferencedBinding" id="_ref_6796"><a href="ecmascript-data-types-and-values.html#sec-initializereferencedbinding">InitializeReferencedBinding</a></emu-xref>(<var>lhs</var>, <var>v</var>).</li></ol></emu-alg> </emu-clause> </emu-clause> </emu-clause> <emu-clause id="sec-empty-statement"> <h1>14.4 Empty Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="EmptyStatement" id="prod-EmptyStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-EmptyStatement">EmptyStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="sg2sawim" id="prod-hl28S5p6"> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-empty-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.4.1 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="EmptyStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-EmptyStatement">EmptyStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="sg2sawim" id="prod-il1Ue5QP"><emu-t>;</emu-t></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-expression-statement"> <h1>14.5 Expression Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="ExpressionStatement" params="Yield, Await" id="prod-ExpressionStatement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="nmo0iroq" id="prod-XGPiPhtM"> <emu-gann>[lookahead ∉ { <emu-t>{</emu-t>, <emu-t>function</emu-t>, <emu-t>async</emu-t> <emu-gann>[no <emu-nt id="_ref_20449"><a href="ecmascript-language-lexical-grammar.html#prod-LineTerminator">LineTerminator</a></emu-nt> here]</emu-gann> <emu-t>function</emu-t>, <emu-t>class</emu-t>, <emu-t>let</emu-t> <emu-t>[</emu-t> }]</emu-gann> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20450"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note<div class="note-contents"> An <emu-nt id="_ref_20451"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a></emu-nt> cannot start with a U+007B (LEFT CURLY BRACKET) because that might make it ambiguous with a <emu-nt id="_ref_20452"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>. An <emu-nt id="_ref_20453"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a></emu-nt> cannot start with the <code>function</code> or <code>class</code> <emu-xref href="#sec-keywords-and-reserved-words" id="_ref_6797"><a href="ecmascript-language-lexical-grammar.html#sec-keywords-and-reserved-words">keywords</a></emu-xref> because that would make it ambiguous with a <emu-nt id="_ref_20454"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt>, a <emu-nt id="_ref_20455"><a href="ecmascript-language-functions-and-classes.html#prod-GeneratorDeclaration">GeneratorDeclaration</a></emu-nt>, or a <emu-nt id="_ref_20456"><a href="ecmascript-language-functions-and-classes.html#prod-ClassDeclaration">ClassDeclaration</a></emu-nt>. An <emu-nt id="_ref_20457"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a></emu-nt> cannot start with <code>async function</code> because that would make it ambiguous with an <emu-nt id="_ref_20458"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncFunctionDeclaration">AsyncFunctionDeclaration</a></emu-nt> or a <emu-nt id="_ref_20459"><a href="ecmascript-language-functions-and-classes.html#prod-AsyncGeneratorDeclaration">AsyncGeneratorDeclaration</a></emu-nt>. An <emu-nt id="_ref_20460"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a></emu-nt> cannot start with the two token sequence <code>let [</code> because that would make it ambiguous with a <code>let</code> <emu-nt id="_ref_20461"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> whose first <emu-nt id="_ref_20462"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalBinding">LexicalBinding</a></emu-nt> was an <emu-nt id="_ref_20463"><a href="ecmascript-language-statements-and-declarations.html#prod-ArrayBindingPattern">ArrayBindingPattern</a></emu-nt>. </div></emu-note> <emu-clause id="sec-expression-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.5.1 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="ExpressionStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="4ttdnuln" id="prod-zmcsioZW"> <emu-nt id="_ref_20464"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6798"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20465"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Return ? <emu-xref aoid="GetValue" id="_ref_6799"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-if-statement"> <h1>14.6 The <code>if</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="IfStatement" params="Yield, Await, Return" id="prod-IfStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gvkksvw-" id="prod-_lf1EvXT"> <emu-t>if</emu-t> <emu-t>(</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20466"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20467"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-t>else</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20468"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="x9p_cd-n" id="prod--e2u-nCd"> <emu-t>if</emu-t> <emu-t>(</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20469"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20470"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-gann>[lookahead ≠ <emu-t>else</emu-t>]</emu-gann> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note<div class="note-contents">The lookahead-restriction [lookahead ≠ <code>else</code>] resolves the classic "dangling else" problem in the usual way. That is, when the choice of associated <code>if</code> is otherwise ambiguous, the <code>else</code> is associated with the nearest (innermost) of the candidate <code>if</code>s</div></emu-note> <emu-clause id="sec-if-statement-static-semantics-early-errors"> <h1>14.6.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="IfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="fuhqe2xq"> <emu-t>if</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20471"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20472"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-t>else</emu-t> <emu-nt id="_ref_20473"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6800"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(the first <emu-nt id="_ref_20474"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6801"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(the second <emu-nt id="_ref_20475"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-grammar><emu-production name="IfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="9ogvciaf"> <emu-t>if</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20476"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20477"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6802"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<emu-nt id="_ref_20478"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-note>Note<div class="note-contents"> It is only necessary to apply this rule if the extension specified in <emu-xref href="#sec-labelled-function-declarations" id="_ref_442"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref> is implemented. </div></emu-note> </emu-clause> <emu-clause id="sec-if-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.6.2 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="IfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="fuhqe2xq" id="prod-V-mFBCSX"> <emu-t>if</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20479"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20480"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-t>else</emu-t> <emu-nt id="_ref_20481"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6803"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20482"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>exprValue</var> be <emu-xref aoid="ToBoolean" id="_ref_6804"><a href="abstract-operations.html#sec-toboolean">ToBoolean</a></emu-xref>(? <emu-xref aoid="GetValue" id="_ref_6805"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>)).</li><li>If <var>exprValue</var> is <emu-val>true</emu-val>, then<ol><li>Let <var>stmtCompletion</var> be <emu-xref aoid="Completion" id="_ref_6806"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6807"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of the first <emu-nt id="_ref_20483"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>).</li></ol></li><li>Else,<ol><li>Let <var>stmtCompletion</var> be <emu-xref aoid="Completion" id="_ref_6808"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6809"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of the second <emu-nt id="_ref_20484"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>).</li></ol></li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_6810"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>stmtCompletion</var>, <emu-val>undefined</emu-val>).</li></ol></emu-alg> <emu-grammar><emu-production name="IfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="9ogvciaf" id="prod-31mgDA5h"> <emu-t>if</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20485"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20486"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6811"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20487"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>exprValue</var> be <emu-xref aoid="ToBoolean" id="_ref_6812"><a href="abstract-operations.html#sec-toboolean">ToBoolean</a></emu-xref>(? <emu-xref aoid="GetValue" id="_ref_6813"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>)).</li><li>If <var>exprValue</var> is <emu-val>false</emu-val>, then<ol><li>Return <emu-val>undefined</emu-val>.</li></ol></li><li>Else,<ol><li>Let <var>stmtCompletion</var> be <emu-xref aoid="Completion" id="_ref_6814"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6815"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20488"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>).</li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_6816"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>stmtCompletion</var>, <emu-val>undefined</emu-val>).</li></ol></li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-iteration-statements"> <h1>14.7 Iteration Statements</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="IterationStatement" params="Yield, Await, Return" id="prod-IterationStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="cfhtf2jt" id="prod-nthWw5bM"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20489"><a href="ecmascript-language-statements-and-declarations.html#prod-DoWhileStatement">DoWhileStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="v6obhs7z" id="prod-J0YbLQ2x"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20490"><a href="ecmascript-language-statements-and-declarations.html#prod-WhileStatement">WhileStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="cito49hq" id="prod-r-Sjm4F3"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20491"><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="ysjy7ne3" id="prod-Q0CapowH"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20492"><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-iteration-statements-semantics"> <h1>14.7.1 Semantics</h1> <emu-clause id="sec-loopcontinues" type="abstract operation" aoid="LoopContinues"> <h1>14.7.1.1 LoopContinues ( <var>completion</var>, <var>labelSet</var> )</h1> The abstract operation LoopContinues takes arguments <var>completion</var> (a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6817"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref>) and <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6818"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns a Boolean. It performs the following steps when called: <emu-alg><ol><li>If <var>completion</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6819"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion</a></emu-xref>, return <emu-val>true</emu-val>.</li><li>If <var>completion</var> is not a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6820"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">continue completion</a></emu-xref>, return <emu-val>false</emu-val>.</li><li>If <var>completion</var>.<var class="field">[[Target]]</var> is <emu-const>empty</emu-const>, return <emu-val>true</emu-val>.</li><li>If <var>labelSet</var> contains <var>completion</var>.<var class="field">[[Target]]</var>, return <emu-val>true</emu-val>.</li><li>Return <emu-val>false</emu-val>.</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> Within the <emu-nt id="_ref_20493"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> part of an <emu-nt id="_ref_20494"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> a <emu-nt id="_ref_20495"><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a></emu-nt> may be used to begin a new iteration. </div></emu-note> </emu-clause> <emu-clause id="sec-runtime-semantics-loopevaluation" type="sdo" aoid="LoopEvaluation"> <h1>14.7.1.2 Runtime Semantics: LoopEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6821"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> LoopEvaluation takes argument <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6822"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6823"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6824"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6825"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="IterationStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="wbcc1u-6" id="prod-bY0mbJsd"><emu-nt id="_ref_20496"><a href="ecmascript-language-statements-and-declarations.html#prod-DoWhileStatement">DoWhileStatement</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="DoWhileLoopEvaluation" id="_ref_6826"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-dowhileloopevaluation" class="e-user-code">DoWhileLoopEvaluation</a></emu-xref> of <emu-nt id="_ref_20497"><a href="ecmascript-language-statements-and-declarations.html#prod-DoWhileStatement">DoWhileStatement</a></emu-nt> with argument <var>labelSet</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="IterationStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="_jk9wnip" id="prod-pBcbxGRB"><emu-nt id="_ref_20498"><a href="ecmascript-language-statements-and-declarations.html#prod-WhileStatement">WhileStatement</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="WhileLoopEvaluation" id="_ref_6827"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-whileloopevaluation" class="e-user-code">WhileLoopEvaluation</a></emu-xref> of <emu-nt id="_ref_20499"><a href="ecmascript-language-statements-and-declarations.html#prod-WhileStatement">WhileStatement</a></emu-nt> with argument <var>labelSet</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="IterationStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="brkouqxh" id="prod-FuTGGBHg"><emu-nt id="_ref_20500"><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="ForLoopEvaluation" id="_ref_6828"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forloopevaluation" class="e-user-code">ForLoopEvaluation</a></emu-xref> of <emu-nt id="_ref_20501"><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt> with argument <var>labelSet</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="IterationStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="wium6lig" id="prod-RfvZcfJK"><emu-nt id="_ref_20502"><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="ForInOfLoopEvaluation" id="_ref_6829"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofloopevaluation" class="e-user-code">ForInOfLoopEvaluation</a></emu-xref> of <emu-nt id="_ref_20503"><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> with argument <var>labelSet</var>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-do-while-statement"> <h1>14.7.2 The <code>do</code>-<code>while</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="DoWhileStatement" params="Yield, Await, Return" id="prod-DoWhileStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-DoWhileStatement">DoWhileStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="eiknjnpu" id="prod-9vnoeXX4"> <emu-t>do</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20504"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-t>while</emu-t> <emu-t>(</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20505"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-do-while-statement-static-semantics-early-errors"> <h1>14.7.2.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="DoWhileStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-DoWhileStatement">DoWhileStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jocmqoht"> <emu-t>do</emu-t> <emu-nt id="_ref_20506"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-t>while</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20507"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6830"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<emu-nt id="_ref_20508"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-note>Note<div class="note-contents"> It is only necessary to apply this rule if the extension specified in <emu-xref href="#sec-labelled-function-declarations" id="_ref_443"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref> is implemented. </div></emu-note> </emu-clause> <emu-clause id="sec-runtime-semantics-dowhileloopevaluation" oldids="sec-do-while-statement-runtime-semantics-labelledevaluation" type="sdo" aoid="DoWhileLoopEvaluation"> <h1>14.7.2.2 Runtime Semantics: DoWhileLoopEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6831"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> DoWhileLoopEvaluation takes argument <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6832"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6833"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6834"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6835"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="DoWhileStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-DoWhileStatement">DoWhileStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jocmqoht" id="prod-3uzJdijq"> <emu-t>do</emu-t> <emu-nt id="_ref_20509"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-t>while</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20510"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>V</var> be <emu-val>undefined</emu-val>.</li><li>Repeat,<ol><li>Let <var>stmtResult</var> be <emu-xref aoid="Completion" id="_ref_6836"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6837"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20511"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>).</li><li>If <emu-xref aoid="LoopContinues" id="_ref_6838"><a href="ecmascript-language-statements-and-declarations.html#sec-loopcontinues">LoopContinues</a></emu-xref>(<var>stmtResult</var>, <var>labelSet</var>) is <emu-val>false</emu-val>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_6839"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>stmtResult</var>, <var>V</var>).</li><li>If <var>stmtResult</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>stmtResult</var>.<var class="field">[[Value]]</var>.</li><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6840"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20512"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>exprValue</var> be ? <emu-xref aoid="GetValue" id="_ref_6841"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li><li>If <emu-xref aoid="ToBoolean" id="_ref_6842"><a href="abstract-operations.html#sec-toboolean">ToBoolean</a></emu-xref>(<var>exprValue</var>) is <emu-val>false</emu-val>, return <var>V</var>.</li></ol></li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-while-statement"> <h1>14.7.3 The <code>while</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="WhileStatement" params="Yield, Await, Return" id="prod-WhileStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-WhileStatement">WhileStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="awcw0xuh" id="prod-Tx40AFG0"> <emu-t>while</emu-t> <emu-t>(</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20513"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20514"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-while-statement-static-semantics-early-errors"> <h1>14.7.3.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="WhileStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-WhileStatement">WhileStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="92j78-b5"> <emu-t>while</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20515"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20516"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6843"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<emu-nt id="_ref_20517"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-note>Note<div class="note-contents"> It is only necessary to apply this rule if the extension specified in <emu-xref href="#sec-labelled-function-declarations" id="_ref_444"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref> is implemented. </div></emu-note> </emu-clause> <emu-clause id="sec-runtime-semantics-whileloopevaluation" oldids="sec-while-statement-runtime-semantics-labelledevaluation" type="sdo" aoid="WhileLoopEvaluation"> <h1>14.7.3.2 Runtime Semantics: WhileLoopEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6844"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> WhileLoopEvaluation takes argument <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6845"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6846"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6847"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6848"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="WhileStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-WhileStatement">WhileStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="92j78-b5" id="prod-0mdwhc7l"> <emu-t>while</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20518"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20519"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>V</var> be <emu-val>undefined</emu-val>.</li><li>Repeat,<ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6849"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20520"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>exprValue</var> be ? <emu-xref aoid="GetValue" id="_ref_6850"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li><li>If <emu-xref aoid="ToBoolean" id="_ref_6851"><a href="abstract-operations.html#sec-toboolean">ToBoolean</a></emu-xref>(<var>exprValue</var>) is <emu-val>false</emu-val>, return <var>V</var>.</li><li>Let <var>stmtResult</var> be <emu-xref aoid="Completion" id="_ref_6852"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6853"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20521"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>).</li><li>If <emu-xref aoid="LoopContinues" id="_ref_6854"><a href="ecmascript-language-statements-and-declarations.html#sec-loopcontinues">LoopContinues</a></emu-xref>(<var>stmtResult</var>, <var>labelSet</var>) is <emu-val>false</emu-val>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_6855"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>stmtResult</var>, <var>V</var>).</li><li>If <var>stmtResult</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>stmtResult</var>.<var class="field">[[Value]]</var>.</li></ol></li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-for-statement"> <h1>14.7.4 The <code>for</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="ForStatement" params="Yield, Await, Return" id="prod-ForStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="honbm3zg" id="prod-NvPgd2yM"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-gann>[lookahead ≠ <emu-t>let</emu-t> <emu-t>[</emu-t>]</emu-gann> <emu-nt params="~In, ?Yield, ?Await" optional="" id="_ref_20522"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[~In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20523"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20524"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20525"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="frhzdc45" id="prod-pYXfSJG_"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt params="~In, ?Yield, ?Await" id="_ref_20526"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a><emu-mods><emu-params>[~In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20527"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20528"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20529"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="ibe-o3pw" id="prod-0Y0bZAvD"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt params="~In, ?Yield, ?Await" id="_ref_20530"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a><emu-mods><emu-params>[~In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20531"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt params="+In, ?Yield, ?Await" optional="" id="_ref_20532"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20533"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-for-statement-static-semantics-early-errors"> <h1>14.7.4.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="ForStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="_do88got"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt optional="" id="_ref_20534"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20535"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20536"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20537"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="sodmtko8"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20538"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20539"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20540"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20541"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="k8b-ryxj"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20542"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> <emu-nt optional="" id="_ref_20543"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20544"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20545"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6856"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<emu-nt id="_ref_20546"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-note>Note<div class="note-contents"> It is only necessary to apply this rule if the extension specified in <emu-xref href="#sec-labelled-function-declarations" id="_ref_445"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref> is implemented. </div></emu-note> <emu-grammar><emu-production name="ForStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="k8b-ryxj"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20547"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> <emu-nt optional="" id="_ref_20548"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20549"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20550"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if any element of the <emu-xref aoid="BoundNames" id="_ref_6857"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20551"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> also occurs in the <emu-xref aoid="VarDeclaredNames" id="_ref_6858"><a href="syntax-directed-operations.html#sec-static-semantics-vardeclarednames">VarDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20552"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>. </li> </ul> </emu-clause> <emu-clause id="sec-runtime-semantics-forloopevaluation" oldids="sec-for-statement-runtime-semantics-labelledevaluation" type="sdo" aoid="ForLoopEvaluation"> <h1>14.7.4.2 Runtime Semantics: ForLoopEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6859"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> ForLoopEvaluation takes argument <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6860"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6861"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6862"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6863"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="ForStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="_do88got" id="prod-qUCVnDNm"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt optional="" id="_ref_20553"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20554"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20555"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20556"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>If the first <emu-nt id="_ref_20557"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, then<ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6864"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of the first <emu-nt id="_ref_20558"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Perform ? <emu-xref aoid="GetValue" id="_ref_6865"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li></ol></li><li>If the second <emu-nt id="_ref_20559"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, let <var>test</var> be the second <emu-nt id="_ref_20560"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>; otherwise, let <var>test</var> be <emu-const>empty</emu-const>.</li><li>If the third <emu-nt id="_ref_20561"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, let <var>increment</var> be the third <emu-nt id="_ref_20562"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>; otherwise, let <var>increment</var> be <emu-const>empty</emu-const>.</li><li>Return ? <emu-xref aoid="ForBodyEvaluation" id="_ref_6866"><a href="ecmascript-language-statements-and-declarations.html#sec-forbodyevaluation" class="e-user-code">ForBodyEvaluation</a></emu-xref>(<var>test</var>, <var>increment</var>, <emu-nt id="_ref_20563"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, « », <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="sodmtko8" id="prod-HwfL-Win"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20564"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20565"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20566"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20567"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Perform ? <emu-xref aoid="Evaluation" id="_ref_6867"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20568"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableDeclarationList">VariableDeclarationList</a></emu-nt>.</li><li>If the first <emu-nt id="_ref_20569"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, let <var>test</var> be the first <emu-nt id="_ref_20570"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>; otherwise, let <var>test</var> be <emu-const>empty</emu-const>.</li><li>If the second <emu-nt id="_ref_20571"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, let <var>increment</var> be the second <emu-nt id="_ref_20572"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>; otherwise, let <var>increment</var> be <emu-const>empty</emu-const>.</li><li>Return ? <emu-xref aoid="ForBodyEvaluation" id="_ref_6868"><a href="ecmascript-language-statements-and-declarations.html#sec-forbodyevaluation" class="e-user-code">ForBodyEvaluation</a></emu-xref>(<var>test</var>, <var>increment</var>, <emu-nt id="_ref_20573"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, « », <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForStatement">ForStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="k8b-ryxj" id="prod-PMtIFugG"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20574"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt> <emu-nt optional="" id="_ref_20575"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>;</emu-t> <emu-nt optional="" id="_ref_20576"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20577"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_6869"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>loopEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_6870"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>oldEnv</var>).</li><li>Let <var>isConst</var> be <emu-xref aoid="IsConstantDeclaration" id="_ref_6871"><a href="syntax-directed-operations.html#sec-static-semantics-isconstantdeclaration">IsConstantDeclaration</a></emu-xref> of <emu-nt id="_ref_20578"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt>.</li><li>Let <var>boundNames</var> be the <emu-xref aoid="BoundNames" id="_ref_6872"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20579"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt>.</li><li>For each element <var>dn</var> of <var>boundNames</var>, do<ol><li>If <var>isConst</var> is <emu-val>true</emu-val>, then<ol><li>Perform ! <var>loopEnv</var>.CreateImmutableBinding(<var>dn</var>, <emu-val>true</emu-val>).</li></ol></li><li>Else,<ol><li>Perform ! <var>loopEnv</var>.CreateMutableBinding(<var>dn</var>, <emu-val>false</emu-val>).</li></ol></li></ol></li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6873"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>loopEnv</var>.</li><li>Let <var>forDcl</var> be <emu-xref aoid="Completion" id="_ref_6874"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6875"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20580"><a href="ecmascript-language-statements-and-declarations.html#prod-LexicalDeclaration">LexicalDeclaration</a></emu-nt>).</li><li>If <var>forDcl</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6876"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, then<ol><li>Set the <emu-xref href="#running-execution-context" id="_ref_6877"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return ? <var>forDcl</var>.</li></ol></li><li>If <var>isConst</var> is <emu-val>false</emu-val>, let <var>perIterationLets</var> be <var>boundNames</var>; otherwise let <var>perIterationLets</var> be a new empty <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6878"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref>.</li><li>If the first <emu-nt id="_ref_20581"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, let <var>test</var> be the first <emu-nt id="_ref_20582"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>; otherwise, let <var>test</var> be <emu-const>empty</emu-const>.</li><li>If the second <emu-nt id="_ref_20583"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is present, let <var>increment</var> be the second <emu-nt id="_ref_20584"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>; otherwise, let <var>increment</var> be <emu-const>empty</emu-const>.</li><li>Let <var>bodyResult</var> be <emu-xref aoid="Completion" id="_ref_6879"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="ForBodyEvaluation" id="_ref_6880"><a href="ecmascript-language-statements-and-declarations.html#sec-forbodyevaluation" class="e-user-code">ForBodyEvaluation</a></emu-xref>(<var>test</var>, <var>increment</var>, <emu-nt id="_ref_20585"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>perIterationLets</var>, <var>labelSet</var>)).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6881"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return ? <var>bodyResult</var>.</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-forbodyevaluation" type="abstract operation" aoid="ForBodyEvaluation"> <h1>14.7.4.3 ForBodyEvaluation ( <var>test</var>, <var>increment</var>, <var>stmt</var>, <var>perIterationBindings</var>, <var>labelSet</var> )</h1> The abstract operation ForBodyEvaluation takes arguments <var>test</var> (an <emu-nt id="_ref_20586"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_6882"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref> or <emu-const>empty</emu-const>), <var>increment</var> (an <emu-nt id="_ref_20587"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_6883"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref> or <emu-const>empty</emu-const>), <var>stmt</var> (a <emu-nt id="_ref_20588"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_6884"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>), <var>perIterationBindings</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6885"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings), and <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6886"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6887"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6888"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6889"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It performs the following steps when called: <emu-alg><ol><li>Let <var>V</var> be <emu-val>undefined</emu-val>.</li><li>Perform ? <emu-xref aoid="CreatePerIterationEnvironment" id="_ref_6890"><a href="ecmascript-language-statements-and-declarations.html#sec-createperiterationenvironment">CreatePerIterationEnvironment</a></emu-xref>(<var>perIterationBindings</var>).</li><li>Repeat,<ol><li>If <var>test</var> is not <emu-const>empty</emu-const>, then<ol><li>Let <var>testRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6891"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>test</var>.</li><li>Let <var>testValue</var> be ? <emu-xref aoid="GetValue" id="_ref_6892"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>testRef</var>).</li><li>If <emu-xref aoid="ToBoolean" id="_ref_6893"><a href="abstract-operations.html#sec-toboolean">ToBoolean</a></emu-xref>(<var>testValue</var>) is <emu-val>false</emu-val>, return <var>V</var>.</li></ol></li><li>Let <var>result</var> be <emu-xref aoid="Completion" id="_ref_6894"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6895"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>stmt</var>).</li><li>If <emu-xref aoid="LoopContinues" id="_ref_6896"><a href="ecmascript-language-statements-and-declarations.html#sec-loopcontinues">LoopContinues</a></emu-xref>(<var>result</var>, <var>labelSet</var>) is <emu-val>false</emu-val>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_6897"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>result</var>, <var>V</var>).</li><li>If <var>result</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>result</var>.<var class="field">[[Value]]</var>.</li><li>Perform ? <emu-xref aoid="CreatePerIterationEnvironment" id="_ref_6898"><a href="ecmascript-language-statements-and-declarations.html#sec-createperiterationenvironment">CreatePerIterationEnvironment</a></emu-xref>(<var>perIterationBindings</var>).</li><li>If <var>increment</var> is not <emu-const>empty</emu-const>, then<ol><li>Let <var>incRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_6899"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>increment</var>.</li><li>Perform ? <emu-xref aoid="GetValue" id="_ref_6900"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>incRef</var>).</li></ol></li></ol></li></ol></emu-alg> </emu-clause> <emu-clause id="sec-createperiterationenvironment" type="abstract operation" aoid="CreatePerIterationEnvironment"> <h1>14.7.4.4 CreatePerIterationEnvironment ( <var>perIterationBindings</var> )</h1> The abstract operation CreatePerIterationEnvironment takes argument <var>perIterationBindings</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6901"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6902"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> <emu-const>unused</emu-const> or a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6903"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">throw completion</a></emu-xref>. It performs the following steps when called: <emu-alg><ol><li>If <var>perIterationBindings</var> has any elements, then<ol><li>Let <var>lastIterationEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_6904"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>outer</var> be <var>lastIterationEnv</var>.<var class="field">[[OuterEnv]]</var>.</li><li><emu-xref href="#assert" id="_ref_6905"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>outer</var> is not <emu-val>null</emu-val>.</li><li>Let <var>thisIterationEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_6906"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>outer</var>).</li><li>For each element <var>bn</var> of <var>perIterationBindings</var>, do<ol><li>Perform ! <var>thisIterationEnv</var>.CreateMutableBinding(<var>bn</var>, <emu-val>false</emu-val>).</li><li>Let <var>lastValue</var> be ? <var>lastIterationEnv</var>.GetBindingValue(<var>bn</var>, <emu-val>true</emu-val>).</li><li>Perform ! <var>thisIterationEnv</var>.InitializeBinding(<var>bn</var>, <var>lastValue</var>).</li></ol></li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6907"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>thisIterationEnv</var>.</li></ol></li><li>Return <emu-const>unused</emu-const>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-for-in-and-for-of-statements"> <h1>14.7.5 The <code>for</code>-<code>in</code>, <code>for</code>-<code>of</code>, and <code>for</code>-<code>await</code>-<code>of</code> Statements</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="ForInOfStatement" params="Yield, Await, Return" id="prod-ForInOfStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="w0xbna_a" id="prod-Za8VIr4f"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-gann>[lookahead ≠ <emu-t>let</emu-t> <emu-t>[</emu-t>]</emu-gann> <emu-nt params="?Yield, ?Await" id="_ref_20589"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>in</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20590"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20591"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="7ml0tbdi" id="prod-_N8Q-kim"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20592"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>in</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20593"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20594"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="zchtsyje" id="prod-xutvwaXc"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20595"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>in</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20596"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20597"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="e8xfsfow" id="prod-nLtPS4oB"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-gann>[lookahead ∉ { <emu-t>let</emu-t>, <emu-t>async</emu-t> <emu-t>of</emu-t> }]</emu-gann> <emu-nt params="?Yield, ?Await" id="_ref_20598"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>of</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20599"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20600"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="58n_2ihn" id="prod-M1zjKbr6"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20601"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>of</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20602"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20603"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="pfvjbka1" id="prod-EoyoF5LI"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20604"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>of</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20605"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20606"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="oprokwwm" constraints="+Await" id="prod-ReDwT2-b"><emu-constraints>[+Await]</emu-constraints> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-gann>[lookahead ≠ <emu-t>let</emu-t>]</emu-gann> <emu-nt params="?Yield, ?Await" id="_ref_20607"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>of</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20608"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20609"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="9bsmrb_a" constraints="+Await" id="prod-ut_uoPzp"><emu-constraints>[+Await]</emu-constraints> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20610"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>of</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20611"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20612"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="fxca1-1x" constraints="+Await" id="prod-jY1gwM9V"><emu-constraints>[+Await]</emu-constraints> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20613"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>of</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20614"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20615"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="ForDeclaration" params="Yield, Await" id="prod-ForDeclaration"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="k6i8qvu4" id="prod-ygJ0cdk1"> <emu-nt id="_ref_20616"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt params="?Yield, ?Await" id="_ref_20617"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="ForBinding" params="Yield, Await" id="prod-ForBinding"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ir-rfjfi" id="prod-gwk9Iaq2"> <emu-nt params="?Yield, ?Await" id="_ref_20618"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="nridwfya" id="prod-rDLkyb_q"> <emu-nt params="?Yield, ?Await" id="_ref_20619"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note<div class="note-contents"> This section is extended by Annex <emu-xref href="#sec-initializers-in-forin-statement-heads" id="_ref_446"><a href="additional-ecmascript-features-for-web-browsers.html#sec-initializers-in-forin-statement-heads">B.3.5</a></emu-xref>. </div></emu-note> <emu-clause id="sec-for-in-and-for-of-statements-static-semantics-early-errors"> <h1>14.7.5.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="ForInOfStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="v1ibcd1w"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20620"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20621"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20622"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="7pgjrcn-"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20623"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20624"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20625"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="jzctgxkp"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20626"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20627"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20628"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="jqzgi_en"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20629"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20630"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20631"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="7m-adytu"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20632"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20633"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20634"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="b3wzboyu"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20635"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20636"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20637"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="mhrux1r7"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20638"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20639"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20640"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="cyt_lv_1"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20641"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20642"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20643"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="uatmda3j"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20644"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20645"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20646"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_6908"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<emu-nt id="_ref_20647"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-note>Note<div class="note-contents"> It is only necessary to apply this rule if the extension specified in <emu-xref href="#sec-labelled-function-declarations" id="_ref_447"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref> is implemented. </div></emu-note> <emu-grammar><emu-production name="ForInOfStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="v1ibcd1w"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20648"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20649"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20650"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="jqzgi_en"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20651"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20652"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20653"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="mhrux1r7"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20654"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20655"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20656"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> If <emu-nt id="_ref_20657"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> is either an <emu-nt id="_ref_20658"><a href="ecmascript-language-expressions.html#prod-ObjectLiteral">ObjectLiteral</a></emu-nt> or an <emu-nt id="_ref_20659"><a href="ecmascript-language-expressions.html#prod-ArrayLiteral">ArrayLiteral</a></emu-nt>, <emu-nt id="_ref_20660"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-xref href="#must-cover" id="_ref_6909"><a href="notational-conventions.html#must-cover">must cover</a></emu-xref> an <emu-nt id="_ref_20661"><a href="ecmascript-language-expressions.html#prod-AssignmentPattern">AssignmentPattern</a></emu-nt>. </li> <li> If <emu-nt id="_ref_20662"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> is neither an <emu-nt id="_ref_20663"><a href="ecmascript-language-expressions.html#prod-ObjectLiteral">ObjectLiteral</a></emu-nt> nor an <emu-nt id="_ref_20664"><a href="ecmascript-language-expressions.html#prod-ArrayLiteral">ArrayLiteral</a></emu-nt>, it is a Syntax Error if the <emu-xref aoid="AssignmentTargetType" id="_ref_6910"><a href="syntax-directed-operations.html#sec-static-semantics-assignmenttargettype">AssignmentTargetType</a></emu-xref> of <emu-nt id="_ref_20665"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> is not <emu-const>simple</emu-const>. </li> </ul> <emu-grammar><emu-production name="ForInOfStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jzctgxkp"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20666"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20667"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20668"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="b3wzboyu"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20669"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20670"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20671"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> <emu-rhs a="uatmda3j"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20672"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20673"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20674"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if the <emu-xref aoid="BoundNames" id="_ref_6911"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20675"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> contains <emu-val>"let"</emu-val>. </li> <li> It is a Syntax Error if any element of the <emu-xref aoid="BoundNames" id="_ref_6912"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20676"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> also occurs in the <emu-xref aoid="VarDeclaredNames" id="_ref_6913"><a href="syntax-directed-operations.html#sec-static-semantics-vardeclarednames">VarDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20677"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>. </li> <li> It is a Syntax Error if the <emu-xref aoid="BoundNames" id="_ref_6914"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20678"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> contains any duplicate entries. </li> </ul> </emu-clause> <emu-clause id="sec-static-semantics-isdestructuring" oldids="sec-static-semantics-static-semantics-isdestructuring,sec-for-in-and-for-of-statements-static-semantics-isdestructuring" type="sdo" aoid="IsDestructuring"> <h1>14.7.5.2 Static Semantics: IsDestructuring</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6915"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> IsDestructuring takes no arguments and returns a Boolean. It is defined piecewise over the following productions: <emu-grammar><emu-production name="MemberExpression" collapsed=""> <emu-nt><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jvcvemtw" id="prod-HvnSrzbi"><emu-nt id="_ref_20679"><a href="ecmascript-language-expressions.html#prod-PrimaryExpression">PrimaryExpression</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>If <emu-nt id="_ref_20680"><a href="ecmascript-language-expressions.html#prod-PrimaryExpression">PrimaryExpression</a></emu-nt> is either an <emu-nt id="_ref_20681"><a href="ecmascript-language-expressions.html#prod-ObjectLiteral">ObjectLiteral</a></emu-nt> or an <emu-nt id="_ref_20682"><a href="ecmascript-language-expressions.html#prod-ArrayLiteral">ArrayLiteral</a></emu-nt>, return <emu-val>true</emu-val>.</li><li>Return <emu-val>false</emu-val>.</li></ol></emu-alg> <emu-grammar><emu-production name="MemberExpression"> <emu-nt><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="a74xd7de" id="prod-nfrnC2qv"> <emu-nt id="_ref_20683"><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-t>[</emu-t> <emu-nt id="_ref_20684"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>]</emu-t> </emu-rhs> <emu-rhs a="frbj984t" id="prod-pVCOt4bB"> <emu-nt id="_ref_20685"><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-t>.</emu-t> <emu-nt id="_ref_20686"><a href="ecmascript-language-lexical-grammar.html#prod-IdentifierName">IdentifierName</a></emu-nt> </emu-rhs> <emu-rhs a="fj52gjle" id="prod-IOJOqU1K"> <emu-nt id="_ref_20687"><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-nt id="_ref_20688"><a href="ecmascript-language-expressions.html#prod-TemplateLiteral">TemplateLiteral</a></emu-nt> </emu-rhs> <emu-rhs a="x4tzletw" id="prod-e3LgGUUv"> <emu-nt id="_ref_20689"><a href="ecmascript-language-expressions.html#prod-SuperProperty">SuperProperty</a></emu-nt> </emu-rhs> <emu-rhs a="yb7id2be" id="prod-uCaMN-Ha"> <emu-nt id="_ref_20690"><a href="ecmascript-language-expressions.html#prod-MetaProperty">MetaProperty</a></emu-nt> </emu-rhs> <emu-rhs a="cfq-hbbx" id="prod-vPeih5lN"> <emu-t>new</emu-t> <emu-nt id="_ref_20691"><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-nt id="_ref_20692"><a href="ecmascript-language-expressions.html#prod-Arguments">Arguments</a></emu-nt> </emu-rhs> <emu-rhs a="0uk9afbi" id="prod-IWE0dD8s"> <emu-nt id="_ref_20693"><a href="ecmascript-language-expressions.html#prod-MemberExpression">MemberExpression</a></emu-nt> <emu-t>.</emu-t> <emu-nt id="_ref_20694"><a href="ecmascript-language-lexical-grammar.html#prod-PrivateIdentifier">PrivateIdentifier</a></emu-nt> </emu-rhs> </emu-production> <emu-production name="NewExpression"> <emu-nt><a href="ecmascript-language-expressions.html#prod-NewExpression">NewExpression</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="51p618ta" id="prod-fNvFZX0j"> <emu-t>new</emu-t> <emu-nt id="_ref_20695"><a href="ecmascript-language-expressions.html#prod-NewExpression">NewExpression</a></emu-nt> </emu-rhs> </emu-production> <emu-production name="LeftHandSideExpression"> <emu-nt><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="i8det4ck" id="prod-9Ion7RwA"> <emu-nt id="_ref_20696"><a href="ecmascript-language-expressions.html#prod-CallExpression">CallExpression</a></emu-nt> </emu-rhs> <emu-rhs a="jbet6xpw" id="prod-Q5WdRWI1"> <emu-nt id="_ref_20697"><a href="ecmascript-language-expressions.html#prod-OptionalExpression">OptionalExpression</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-val>false</emu-val>.</li></ol></emu-alg> <emu-grammar><emu-production name="ForDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="0y1vvm1x" id="prod-gowHZDoa"> <emu-nt id="_ref_20698"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt id="_ref_20699"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-xref aoid="IsDestructuring" id="_ref_6916"><a href="ecmascript-language-statements-and-declarations.html#sec-static-semantics-isdestructuring">IsDestructuring</a></emu-xref> of <emu-nt id="_ref_20700"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt>.</li></ol></emu-alg> <emu-grammar><emu-production name="ForBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uolyom43" id="prod-AsYWUqR1"><emu-nt id="_ref_20701"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-val>false</emu-val>.</li></ol></emu-alg> <emu-grammar><emu-production name="ForBinding" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="mdrfyhm6" id="prod-n6CWa3rF"><emu-nt id="_ref_20702"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-val>true</emu-val>.</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> This section is extended by Annex <emu-xref href="#sec-initializers-in-forin-statement-heads" id="_ref_448"><a href="additional-ecmascript-features-for-web-browsers.html#sec-initializers-in-forin-statement-heads">B.3.5</a></emu-xref>. </div></emu-note> </emu-clause> <emu-clause id="sec-runtime-semantics-fordeclarationbindinginitialization" oldids="sec-for-in-and-for-of-statements-runtime-semantics-bindinginitialization" type="sdo" aoid="ForDeclarationBindingInitialization"> <h1>14.7.5.3 Runtime Semantics: ForDeclarationBindingInitialization</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6917"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> ForDeclarationBindingInitialization takes arguments <var>value</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6918"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and <var>environment</var> (an <emu-xref href="#sec-environment-records" id="_ref_6919"><a href="executable-code-and-execution-contexts.html#sec-environment-records">Environment Record</a></emu-xref> or <emu-val>undefined</emu-val>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6920"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> <emu-const>unused</emu-const> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6921"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. <emu-note>Note<div class="note-contents"> <emu-val>undefined</emu-val> is passed for <var>environment</var> to indicate that a <emu-xref aoid="PutValue" id="_ref_6922"><a href="ecmascript-data-types-and-values.html#sec-putvalue">PutValue</a></emu-xref> operation should be used to assign the initialization value. This is the case for <code>var</code> statements and the formal parameter lists of some <emu-xref href="#non-strict-function" id="_ref_6923"><a href="ordinary-and-exotic-objects-behaviours.html#non-strict-function">non-strict functions</a></emu-xref> (see <emu-xref href="#sec-functiondeclarationinstantiation" id="_ref_449"><a href="ordinary-and-exotic-objects-behaviours.html#sec-functiondeclarationinstantiation">10.2.11</a></emu-xref>). In those cases a lexical binding is hoisted and preinitialized prior to evaluation of its initializer. </div></emu-note> It is defined piecewise over the following productions: <emu-grammar><emu-production name="ForDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="0y1vvm1x" id="prod-S5lZ05os"> <emu-nt id="_ref_20703"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt id="_ref_20704"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="BindingInitialization" id="_ref_6924"><a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" class="e-user-code">BindingInitialization</a></emu-xref> of <emu-nt id="_ref_20705"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> with arguments <var>value</var> and <var>environment</var>.</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-runtime-semantics-fordeclarationbindinginstantiation" oldids="sec-runtime-semantics-bindinginstantiation" type="sdo" aoid="ForDeclarationBindingInstantiation"> <h1>14.7.5.4 Runtime Semantics: ForDeclarationBindingInstantiation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6925"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> ForDeclarationBindingInstantiation takes argument <var>environment</var> (a <emu-xref href="#sec-declarative-environment-records" id="_ref_6926"><a href="executable-code-and-execution-contexts.html#sec-declarative-environment-records">Declarative Environment Record</a></emu-xref>) and returns <emu-const>unused</emu-const>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="ForDeclaration" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="0y1vvm1x" id="prod-bTiDTykL"> <emu-nt id="_ref_20706"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> <emu-nt id="_ref_20707"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>For each element <var>name</var> of the <emu-xref aoid="BoundNames" id="_ref_6927"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20708"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt>, do<ol><li>If <emu-xref aoid="IsConstantDeclaration" id="_ref_6928"><a href="syntax-directed-operations.html#sec-static-semantics-isconstantdeclaration">IsConstantDeclaration</a></emu-xref> of <emu-nt id="_ref_20709"><a href="ecmascript-language-statements-and-declarations.html#prod-LetOrConst">LetOrConst</a></emu-nt> is <emu-val>true</emu-val>, then<ol><li>Perform ! <var>environment</var>.CreateImmutableBinding(<var>name</var>, <emu-val>true</emu-val>).</li></ol></li><li>Else,<ol><li>Perform ! <var>environment</var>.CreateMutableBinding(<var>name</var>, <emu-val>false</emu-val>).</li></ol></li></ol></li><li>Return <emu-const>unused</emu-const>.</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-runtime-semantics-forinofloopevaluation" oldids="sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation" type="sdo" aoid="ForInOfLoopEvaluation"> <h1>14.7.5.5 Runtime Semantics: ForInOfLoopEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_6929"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> ForInOfLoopEvaluation takes argument <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6930"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6931"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6932"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6933"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="v1ibcd1w" id="prod-dhS3iRZF"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20710"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20711"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20712"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6934"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(« », <emu-nt id="_ref_20713"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>, <emu-const>enumerate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6935"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20714"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt>, <emu-nt id="_ref_20715"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>enumerate</emu-const>, <emu-const>assignment</emu-const>, <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="7pgjrcn-" id="prod-A6rVBZNm"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20716"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20717"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20718"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6936"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(« », <emu-nt id="_ref_20719"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>, <emu-const>enumerate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6937"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20720"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt>, <emu-nt id="_ref_20721"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>enumerate</emu-const>, <emu-const>var-binding</emu-const>, <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jzctgxkp" id="prod-zcGoySgU"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20722"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>in</emu-t> <emu-nt id="_ref_20723"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20724"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6938"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(<emu-xref aoid="BoundNames" id="_ref_6939"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20725"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>, <emu-nt id="_ref_20726"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>, <emu-const>enumerate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6940"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20727"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>, <emu-nt id="_ref_20728"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>enumerate</emu-const>, <emu-const>lexical-binding</emu-const>, <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="jqzgi_en" id="prod-xXfkt6k0"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20729"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20730"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20731"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6941"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(« », <emu-nt id="_ref_20732"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt>, <emu-const>iterate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6942"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20733"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt>, <emu-nt id="_ref_20734"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>iterate</emu-const>, <emu-const>assignment</emu-const>, <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="7m-adytu" id="prod-pPrWP7Ph"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20735"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20736"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20737"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6943"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(« », <emu-nt id="_ref_20738"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt>, <emu-const>iterate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6944"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20739"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt>, <emu-nt id="_ref_20740"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>iterate</emu-const>, <emu-const>var-binding</emu-const>, <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="b3wzboyu" id="prod-OIo-GNlm"> <emu-t>for</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20741"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20742"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20743"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6945"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(<emu-xref aoid="BoundNames" id="_ref_6946"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20744"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>, <emu-nt id="_ref_20745"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt>, <emu-const>iterate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6947"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20746"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>, <emu-nt id="_ref_20747"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>iterate</emu-const>, <emu-const>lexical-binding</emu-const>, <var>labelSet</var>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="mhrux1r7" id="prod-Z4scLosS"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20748"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20749"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20750"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6948"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(« », <emu-nt id="_ref_20751"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt>, <emu-const>async-iterate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6949"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20752"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt>, <emu-nt id="_ref_20753"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>iterate</emu-const>, <emu-const>assignment</emu-const>, <var>labelSet</var>, <emu-const>async</emu-const>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="cyt_lv_1" id="prod-5PDN6AV3"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-t>var</emu-t> <emu-nt id="_ref_20754"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20755"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20756"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6950"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(« », <emu-nt id="_ref_20757"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt>, <emu-const>async-iterate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6951"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20758"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt>, <emu-nt id="_ref_20759"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>iterate</emu-const>, <emu-const>var-binding</emu-const>, <var>labelSet</var>, <emu-const>async</emu-const>).</li></ol></emu-alg> <emu-grammar><emu-production name="ForInOfStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ForInOfStatement">ForInOfStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uatmda3j" id="prod-KdWnMB6i"> <emu-t>for</emu-t> <emu-t>await</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20760"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt> <emu-t>of</emu-t> <emu-nt id="_ref_20761"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20762"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>keyResult</var> be ? <emu-xref aoid="ForIn/OfHeadEvaluation" id="_ref_6952"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forinofheadevaluation" class="e-user-code">ForIn/OfHeadEvaluation</a></emu-xref>(<emu-xref aoid="BoundNames" id="_ref_6953"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20763"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>, <emu-nt id="_ref_20764"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt>, <emu-const>async-iterate</emu-const>).</li><li>Return ? <emu-xref aoid="ForIn/OfBodyEvaluation" id="_ref_6954"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" class="e-user-code">ForIn/OfBodyEvaluation</a></emu-xref>(<emu-nt id="_ref_20765"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>, <emu-nt id="_ref_20766"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, <var>keyResult</var>, <emu-const>iterate</emu-const>, <emu-const>lexical-binding</emu-const>, <var>labelSet</var>, <emu-const>async</emu-const>).</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> This section is extended by Annex <emu-xref href="#sec-initializers-in-forin-statement-heads" id="_ref_450"><a href="additional-ecmascript-features-for-web-browsers.html#sec-initializers-in-forin-statement-heads">B.3.5</a></emu-xref>. </div></emu-note> </emu-clause> <emu-clause id="sec-runtime-semantics-forinofheadevaluation" type="abstract operation" oldids="sec-runtime-semantics-forin-div-ofheadevaluation-tdznames-expr-iterationkind" aoid="ForIn/OfHeadEvaluation"> <h1>14.7.5.6 ForIn/OfHeadEvaluation ( <var>uninitializedBoundNames</var>, <var>expr</var>, <var>iterationKind</var> )</h1> The abstract operation ForIn/OfHeadEvaluation takes arguments <var>uninitializedBoundNames</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6955"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings), <var>expr</var> (an <emu-nt id="_ref_20767"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_6956"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref> or an <emu-nt id="_ref_20768"><a href="ecmascript-language-expressions.html#prod-AssignmentExpression">AssignmentExpression</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_6957"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>), and <var>iterationKind</var> (<emu-const>enumerate</emu-const>, <emu-const>iterate</emu-const>, or <emu-const>async-iterate</emu-const>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6958"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-iterator-records" id="_ref_6959"><a href="abstract-operations.html#sec-iterator-records">Iterator Record</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6960"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It performs the following steps when called: <emu-alg><ol><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_6961"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>If <var>uninitializedBoundNames</var> is not empty, then<ol><li><emu-xref href="#assert" id="_ref_6962"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>uninitializedBoundNames</var> has no duplicate entries.</li><li>Let <var>newEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_6963"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>oldEnv</var>).</li><li>For each String <var>name</var> of <var>uninitializedBoundNames</var>, do<ol><li>Perform ! <var>newEnv</var>.CreateMutableBinding(<var>name</var>, <emu-val>false</emu-val>).</li></ol></li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6964"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>newEnv</var>.</li></ol></li><li>Let <var>exprRef</var> be <emu-xref aoid="Completion" id="_ref_6965"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6966"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>expr</var>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_6967"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Let <var>exprValue</var> be ? <emu-xref aoid="GetValue" id="_ref_6968"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(? <var>exprRef</var>).</li><li>If <var>iterationKind</var> is <emu-const>enumerate</emu-const>, then<ol><li>If <var>exprValue</var> is either <emu-val>undefined</emu-val> or <emu-val>null</emu-val>, then<ol><li>Return <emu-xref href="#sec-completion-record-specification-type" id="_ref_6969"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> { <var class="field">[[Type]]</var>: <emu-const>break</emu-const>, <var class="field">[[Value]]</var>: <emu-const>empty</emu-const>, <var class="field">[[Target]]</var>: <emu-const>empty</emu-const> }.</li></ol></li><li>Let <var>obj</var> be ! <emu-xref aoid="ToObject" id="_ref_6970"><a href="abstract-operations.html#sec-toobject">ToObject</a></emu-xref>(<var>exprValue</var>).</li><li>Let <var>iterator</var> be <emu-xref aoid="EnumerateObjectProperties" id="_ref_6971"><a href="ecmascript-language-statements-and-declarations.html#sec-enumerate-object-properties">EnumerateObjectProperties</a></emu-xref>(<var>obj</var>).</li><li>Let <var>nextMethod</var> be ! <emu-xref aoid="GetV" id="_ref_6972"><a href="abstract-operations.html#sec-getv">GetV</a></emu-xref>(<var>iterator</var>, <emu-val>"next"</emu-val>).</li><li>Return the <emu-xref href="#sec-iterator-records" id="_ref_6973"><a href="abstract-operations.html#sec-iterator-records">Iterator Record</a></emu-xref> { <var class="field">[[Iterator]]</var>: <var>iterator</var>, <var class="field">[[NextMethod]]</var>: <var>nextMethod</var>, <var class="field">[[Done]]</var>: <emu-val>false</emu-val> }.</li></ol></li><li>Else,<ol><li><emu-xref href="#assert" id="_ref_6974"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>iterationKind</var> is either <emu-const>iterate</emu-const> or <emu-const>async-iterate</emu-const>.</li><li>If <var>iterationKind</var> is <emu-const>async-iterate</emu-const>, let <var>iteratorKind</var> be <emu-const>async</emu-const>.</li><li>Else, let <var>iteratorKind</var> be <emu-const>sync</emu-const>.</li><li>Return ? <emu-xref aoid="GetIterator" id="_ref_6975"><a href="abstract-operations.html#sec-getiterator" class="e-user-code">GetIterator</a></emu-xref>(<var>exprValue</var>, <var>iteratorKind</var>).</li></ol></li></ol></emu-alg> </emu-clause> <emu-clause id="sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset" type="abstract operation" aoid="ForIn/OfBodyEvaluation"> <h1>14.7.5.7 ForIn/OfBodyEvaluation ( <var>lhs</var>, <var>stmt</var>, <var>iteratorRecord</var>, <var>iterationKind</var>, <var>lhsKind</var>, <var>labelSet</var> [ , <var>iteratorKind</var> ] )</h1> The abstract operation ForIn/OfBodyEvaluation takes arguments <var>lhs</var> (a <emu-xref href="#sec-syntactic-grammar" id="_ref_6976"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>), <var>stmt</var> (a <emu-nt id="_ref_20769"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_6977"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>), <var>iteratorRecord</var> (an <emu-xref href="#sec-iterator-records" id="_ref_6978"><a href="abstract-operations.html#sec-iterator-records">Iterator Record</a></emu-xref>), <var>iterationKind</var> (<emu-const>enumerate</emu-const> or <emu-const>iterate</emu-const>), <var>lhsKind</var> (<emu-const>assignment</emu-const>, <emu-const>var-binding</emu-const>, or <emu-const>lexical-binding</emu-const>), and <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_6979"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and optional argument <var>iteratorKind</var> (<emu-const>sync</emu-const> or <emu-const>async</emu-const>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_6980"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_6981"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_6982"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It performs the following steps when called: <emu-alg><ol><li>If <var>iteratorKind</var> is not present, set <var>iteratorKind</var> to <emu-const>sync</emu-const>.</li><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_6983"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>V</var> be <emu-val>undefined</emu-val>.</li><li>Let <var>destructuring</var> be <emu-xref aoid="IsDestructuring" id="_ref_6984"><a href="ecmascript-language-statements-and-declarations.html#sec-static-semantics-isdestructuring">IsDestructuring</a></emu-xref> of <var>lhs</var>.</li><li>If <var>destructuring</var> is <emu-val>true</emu-val> and <var>lhsKind</var> is <emu-const>assignment</emu-const>, then<ol><li><emu-xref href="#assert" id="_ref_6985"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>lhs</var> is a <emu-nt id="_ref_20770"><a href="ecmascript-language-expressions.html#prod-LeftHandSideExpression">LeftHandSideExpression</a></emu-nt>.</li><li>Let <var>assignmentPattern</var> be the <emu-nt id="_ref_20771"><a href="ecmascript-language-expressions.html#prod-AssignmentPattern">AssignmentPattern</a></emu-nt> that is <emu-xref href="#sec-syntactic-grammar" id="_ref_6986"><a href="notational-conventions.html#sec-syntactic-grammar">covered</a></emu-xref> by <var>lhs</var>.</li></ol></li><li>Repeat,<ol><li>Let <var>nextResult</var> be ? <emu-xref aoid="Call" id="_ref_6987"><a href="abstract-operations.html#sec-call" class="e-user-code">Call</a></emu-xref>(<var>iteratorRecord</var>.<var class="field">[[NextMethod]]</var>, <var>iteratorRecord</var>.<var class="field">[[Iterator]]</var>).</li><li>If <var>iteratorKind</var> is <emu-const>async</emu-const>, set <var>nextResult</var> to ? <emu-xref aoid="Await" id="_ref_6988"><a href="control-abstraction-objects.html#await" class="e-user-code">Await</a></emu-xref>(<var>nextResult</var>).</li><li>If <var>nextResult</var> <emu-xref href="#sec-object-type" id="_ref_6989"><a href="ecmascript-data-types-and-values.html#sec-object-type">is not an Object</a></emu-xref>, throw a <emu-val>TypeError</emu-val> exception.</li><li>Let <var>done</var> be ? <emu-xref aoid="IteratorComplete" id="_ref_6990"><a href="abstract-operations.html#sec-iteratorcomplete" class="e-user-code">IteratorComplete</a></emu-xref>(<var>nextResult</var>).</li><li>If <var>done</var> is <emu-val>true</emu-val>, return <var>V</var>.</li><li>Let <var>nextValue</var> be ? <emu-xref aoid="IteratorValue" id="_ref_6991"><a href="abstract-operations.html#sec-iteratorvalue" class="e-user-code">IteratorValue</a></emu-xref>(<var>nextResult</var>).</li><li>If <var>lhsKind</var> is either <emu-const>assignment</emu-const> or <emu-const>var-binding</emu-const>, then<ol><li>If <var>destructuring</var> is <emu-val>true</emu-val>, then<ol><li>If <var>lhsKind</var> is <emu-const>assignment</emu-const>, then<ol><li>Let <var>status</var> be <emu-xref aoid="Completion" id="_ref_6992"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="DestructuringAssignmentEvaluation" id="_ref_6993"><a href="ecmascript-language-expressions.html#sec-runtime-semantics-destructuringassignmentevaluation" class="e-user-code">DestructuringAssignmentEvaluation</a></emu-xref> of <var>assignmentPattern</var> with argument <var>nextValue</var>).</li></ol></li><li>Else,<ol><li><emu-xref href="#assert" id="_ref_6994"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>lhsKind</var> is <emu-const>var-binding</emu-const>.</li><li><emu-xref href="#assert" id="_ref_6995"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>lhs</var> is a <emu-nt id="_ref_20772"><a href="ecmascript-language-statements-and-declarations.html#prod-ForBinding">ForBinding</a></emu-nt>.</li><li>Let <var>status</var> be <emu-xref aoid="Completion" id="_ref_6996"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="BindingInitialization" id="_ref_6997"><a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" class="e-user-code">BindingInitialization</a></emu-xref> of <var>lhs</var> with arguments <var>nextValue</var> and <emu-val>undefined</emu-val>).</li></ol></li></ol></li><li>Else,<ol><li>Let <var>lhsRef</var> be <emu-xref aoid="Completion" id="_ref_6998"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_6999"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>lhs</var>). (It may be evaluated repeatedly.)</li><li>If <var>lhsRef</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7000"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, then<ol><li>Let <var>status</var> be <var>lhsRef</var>.</li></ol></li><li>Else,<ol><li>Let <var>status</var> be <emu-xref aoid="Completion" id="_ref_7001"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="PutValue" id="_ref_7002"><a href="ecmascript-data-types-and-values.html#sec-putvalue" class="e-user-code">PutValue</a></emu-xref>(<var>lhsRef</var>.<var class="field">[[Value]]</var>, <var>nextValue</var>)).</li></ol></li></ol></li></ol></li><li>Else,<ol><li><emu-xref href="#assert" id="_ref_7003"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>lhsKind</var> is <emu-const>lexical-binding</emu-const>.</li><li><emu-xref href="#assert" id="_ref_7004"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>lhs</var> is a <emu-nt id="_ref_20773"><a href="ecmascript-language-statements-and-declarations.html#prod-ForDeclaration">ForDeclaration</a></emu-nt>.</li><li>Let <var>iterationEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_7005"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>oldEnv</var>).</li><li>Perform <emu-xref aoid="ForDeclarationBindingInstantiation" id="_ref_7006"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-fordeclarationbindinginstantiation">ForDeclarationBindingInstantiation</a></emu-xref> of <var>lhs</var> with argument <var>iterationEnv</var>.</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7007"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>iterationEnv</var>.</li><li>If <var>destructuring</var> is <emu-val>true</emu-val>, then<ol><li>Let <var>status</var> be <emu-xref aoid="Completion" id="_ref_7008"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="ForDeclarationBindingInitialization" id="_ref_7009"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-fordeclarationbindinginitialization" class="e-user-code">ForDeclarationBindingInitialization</a></emu-xref> of <var>lhs</var> with arguments <var>nextValue</var> and <var>iterationEnv</var>).</li></ol></li><li>Else,<ol><li><emu-xref href="#assert" id="_ref_7010"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>lhs</var> binds a single name.</li><li>Let <var>lhsName</var> be the sole element of the <emu-xref aoid="BoundNames" id="_ref_7011"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <var>lhs</var>.</li><li>Let <var>lhsRef</var> be ! <emu-xref aoid="ResolveBinding" id="_ref_7012"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding">ResolveBinding</a></emu-xref>(<var>lhsName</var>).</li><li>Let <var>status</var> be <emu-xref aoid="Completion" id="_ref_7013"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="InitializeReferencedBinding" id="_ref_7014"><a href="ecmascript-data-types-and-values.html#sec-initializereferencedbinding">InitializeReferencedBinding</a></emu-xref>(<var>lhsRef</var>, <var>nextValue</var>)).</li></ol></li></ol></li><li>If <var>status</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7015"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, then<ol><li>Set the <emu-xref href="#running-execution-context" id="_ref_7016"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>If <var>iteratorKind</var> is <emu-const>async</emu-const>, return ? <emu-xref aoid="AsyncIteratorClose" id="_ref_7017"><a href="abstract-operations.html#sec-asynciteratorclose" class="e-user-code">AsyncIteratorClose</a></emu-xref>(<var>iteratorRecord</var>, <var>status</var>).</li><li>If <var>iterationKind</var> is <emu-const>enumerate</emu-const>, then<ol><li>Return ? <var>status</var>.</li></ol></li><li>Else,<ol><li><emu-xref href="#assert" id="_ref_7018"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>iterationKind</var> is <emu-const>iterate</emu-const>.</li><li>Return ? <emu-xref aoid="IteratorClose" id="_ref_7019"><a href="abstract-operations.html#sec-iteratorclose" class="e-user-code">IteratorClose</a></emu-xref>(<var>iteratorRecord</var>, <var>status</var>).</li></ol></li></ol></li><li>Let <var>result</var> be <emu-xref aoid="Completion" id="_ref_7020"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7021"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>stmt</var>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7022"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>If <emu-xref aoid="LoopContinues" id="_ref_7023"><a href="ecmascript-language-statements-and-declarations.html#sec-loopcontinues">LoopContinues</a></emu-xref>(<var>result</var>, <var>labelSet</var>) is <emu-val>false</emu-val>, then<ol><li>If <var>iterationKind</var> is <emu-const>enumerate</emu-const>, then<ol><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_7024"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>result</var>, <var>V</var>).</li></ol></li><li>Else,<ol><li><emu-xref href="#assert" id="_ref_7025"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>iterationKind</var> is <emu-const>iterate</emu-const>.</li><li>Set <var>status</var> to <emu-xref aoid="Completion" id="_ref_7026"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="UpdateEmpty" id="_ref_7027"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>result</var>, <var>V</var>)).</li><li>If <var>iteratorKind</var> is <emu-const>async</emu-const>, return ? <emu-xref aoid="AsyncIteratorClose" id="_ref_7028"><a href="abstract-operations.html#sec-asynciteratorclose" class="e-user-code">AsyncIteratorClose</a></emu-xref>(<var>iteratorRecord</var>, <var>status</var>).</li><li>Return ? <emu-xref aoid="IteratorClose" id="_ref_7029"><a href="abstract-operations.html#sec-iteratorclose" class="e-user-code">IteratorClose</a></emu-xref>(<var>iteratorRecord</var>, <var>status</var>).</li></ol></li></ol></li><li>If <var>result</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>result</var>.<var class="field">[[Value]]</var>.</li></ol></li></ol></emu-alg> </emu-clause> <emu-clause id="sec-for-in-and-for-of-statements-runtime-semantics-evaluation" type="sdo"> <h1>14.7.5.8 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="BindingIdentifier"> <emu-nt><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="bras6mo_" id="prod-_anR-waH"> <emu-nt id="_ref_20774"><a href="ecmascript-language-expressions.html#prod-Identifier">Identifier</a></emu-nt> </emu-rhs> <emu-rhs a="0d8zyjn8" id="prod-K8Yvyf4p"> <emu-t>yield</emu-t> </emu-rhs> <emu-rhs a="hx1dvlrw" id="prod-KzQjZu5p"> <emu-t>await</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>bindingId</var> be the <emu-xref aoid="StringValue" id="_ref_7030"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20775"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a></emu-nt>.</li><li>Return ? <emu-xref aoid="ResolveBinding" id="_ref_7031"><a href="executable-code-and-execution-contexts.html#sec-resolvebinding" class="e-user-code">ResolveBinding</a></emu-xref>(<var>bindingId</var>).</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-enumerate-object-properties" type="abstract operation" aoid="EnumerateObjectProperties"> <h1>14.7.5.9 EnumerateObjectProperties ( <var>O</var> )</h1> The abstract operation EnumerateObjectProperties takes argument <var>O</var> (an Object) and returns an <emu-xref href="#sec-iterator-interface" id="_ref_7032"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator object</a></emu-xref>. It performs the following steps when called: <emu-alg><ol><li>Return an <emu-xref href="#sec-iterator-interface" id="_ref_7033"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator object</a></emu-xref> whose <code>next</code> method iterates over all the String-valued keys of enumerable properties of <var>O</var>. The <emu-xref href="#sec-iterator-interface" id="_ref_7034"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator object</a></emu-xref> is never directly accessible to ECMAScript code. The mechanics and order of enumerating the properties is not specified but must conform to the rules specified below.</li></ol></emu-alg> The <emu-xref href="#sec-iterator-interface" id="_ref_7035"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref>'s <code>throw</code> and <code>return</code> methods are <emu-val>null</emu-val> and are never invoked. The <emu-xref href="#sec-iterator-interface" id="_ref_7036"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref>'s <code>next</code> method processes object properties to determine whether the <emu-xref href="#sec-object-type" id="_ref_7037"><a href="ecmascript-data-types-and-values.html#sec-object-type">property key</a></emu-xref> should be returned as an <emu-xref href="#sec-iterator-interface" id="_ref_7038"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref> value. Returned <emu-xref href="#sec-object-type" id="_ref_7039"><a href="ecmascript-data-types-and-values.html#sec-object-type">property keys</a></emu-xref> do not include keys that are Symbols. Properties of the target object may be deleted during enumeration. A property that is deleted before it is processed by the <emu-xref href="#sec-iterator-interface" id="_ref_7040"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref>'s <code>next</code> method is ignored. If new properties are added to the target object during enumeration, the newly added properties are not guaranteed to be processed in the active enumeration. A <emu-xref href="#property-name" id="_ref_7041"><a href="ecmascript-data-types-and-values.html#property-name">property name</a></emu-xref> will be returned by the <emu-xref href="#sec-iterator-interface" id="_ref_7042"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref>'s <code>next</code> method at most once in any enumeration. Enumerating the properties of the target object includes enumerating properties of its prototype, and the prototype of the prototype, and so on, recursively; but a property of a prototype is not processed if it has the same name as a property that has already been processed by the <emu-xref href="#sec-iterator-interface" id="_ref_7043"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref>'s <code>next</code> method. The values of <var class="field">[[Enumerable]]</var> attributes are not considered when determining if a property of a prototype object has already been processed. The enumerable property names of prototype objects must be obtained by invoking EnumerateObjectProperties passing the prototype object as the argument. EnumerateObjectProperties must obtain the own <emu-xref href="#sec-object-type" id="_ref_7044"><a href="ecmascript-data-types-and-values.html#sec-object-type">property keys</a></emu-xref> of the target object by calling its <var class="field">[[OwnPropertyKeys]]</var> internal method. Property attributes of the target object must be obtained by calling its <var class="field">[[GetOwnProperty]]</var> internal method. In addition, if neither <var>O</var> nor any object in its prototype chain is a <emu-xref href="#proxy-exotic-object" id="_ref_7045"><a href="ordinary-and-exotic-objects-behaviours.html#proxy-exotic-object">Proxy exotic object</a></emu-xref>, <emu-xref href="#typedarray" id="_ref_7046"><a href="ordinary-and-exotic-objects-behaviours.html#typedarray">TypedArray</a></emu-xref>, <emu-xref href="#module-namespace-exotic-object" id="_ref_7047"><a href="ordinary-and-exotic-objects-behaviours.html#module-namespace-exotic-object">module namespace exotic object</a></emu-xref>, or implementation provided <emu-xref href="#exotic-object" id="_ref_7048"><a href="ecmascript-data-types-and-values.html#exotic-object">exotic object</a></emu-xref>, then the <emu-xref href="#sec-iterator-interface" id="_ref_7049"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref> must behave as would the <emu-xref href="#sec-iterator-interface" id="_ref_7050"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref> given by <emu-xref aoid="CreateForInIterator" id="_ref_7051"><a href="ecmascript-language-statements-and-declarations.html#sec-createforiniterator">CreateForInIterator</a></emu-xref>(<var>O</var>) until one of the following occurs: <ul> <li>the value of the <var class="field">[[Prototype]]</var> internal slot of <var>O</var> or an object in its prototype chain changes,</li> <li>a property is removed from <var>O</var> or an object in its prototype chain,</li> <li>a property is added to an object in <var>O</var>'s prototype chain, or</li> <li>the value of the <var class="field">[[Enumerable]]</var> attribute of a property of <var>O</var> or an object in its prototype chain changes.</li> </ul> <emu-note>Note 1<div class="note-contents"> ECMAScript implementations are not required to implement the algorithm in <emu-xref href="#sec-%foriniteratorprototype%.next" id="_ref_451"><a href="ecmascript-language-statements-and-declarations.html#sec-%foriniteratorprototype%.next">14.7.5.10.2.1</a></emu-xref> directly. They may choose any implementation whose behaviour will not deviate from that algorithm unless one of the constraints in the previous paragraph is violated. The following is an informative definition of an ECMAScript generator function that conforms to these rules: <pre><code class="javascript hljs">function* EnumerateObjectProperties(obj) { const visited = new Set(); for (const key of Reflect.ownKeys(obj)) { if (typeof key === "symbol") continue; const desc = Reflect.getOwnPropertyDescriptor(obj, key); if (desc) { visited.add(key); if (desc.enumerable) yield key; } } const proto = Reflect.getPrototypeOf(obj); if (proto === null) return; for (const protoKey of EnumerateObjectProperties(proto)) { if (!visited.has(protoKey)) yield protoKey; } }</code></pre> </div></emu-note> <emu-note>Note 2<div class="note-contents"> The list of <emu-xref href="#exotic-object" id="_ref_7052"><a href="ecmascript-data-types-and-values.html#exotic-object">exotic objects</a></emu-xref> for which implementations are not required to match <emu-xref aoid="CreateForInIterator" id="_ref_7053"><a href="ecmascript-language-statements-and-declarations.html#sec-createforiniterator">CreateForInIterator</a></emu-xref> was chosen because implementations historically differed in behaviour for those cases, and agreed in all others. </div></emu-note> </emu-clause> <emu-clause id="sec-for-in-iterator-objects"> <h1>14.7.5.10 For-In Iterator Objects</h1> A <dfn variants="For-In Iterator object,For-In Iterator objects" tabindex="-1">For-In Iterator</dfn> is an object that represents a specific iteration over some specific object. For-In Iterator objects are never directly accessible to ECMAScript code; they exist solely to illustrate the behaviour of <emu-xref aoid="EnumerateObjectProperties" id="_ref_7054"><a href="ecmascript-language-statements-and-declarations.html#sec-enumerate-object-properties">EnumerateObjectProperties</a></emu-xref>. <emu-clause id="sec-createforiniterator" type="abstract operation" aoid="CreateForInIterator"> <h1>14.7.5.10.1 CreateForInIterator ( <var>object</var> )</h1> The abstract operation CreateForInIterator takes argument <var>object</var> (an Object) and returns a <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7055"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator</a></emu-xref>. It is used to create a <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7056"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator object</a></emu-xref> which iterates over the own and inherited enumerable string properties of <var>object</var> in a specific order. It performs the following steps when called: <emu-alg><ol><li>Let <var>iterator</var> be <emu-xref aoid="OrdinaryObjectCreate" id="_ref_7057"><a href="ordinary-and-exotic-objects-behaviours.html#sec-ordinaryobjectcreate">OrdinaryObjectCreate</a></emu-xref>(<emu-xref href="#sec-%foriniteratorprototype%-object" id="_ref_7058"><a href="ecmascript-language-statements-and-declarations.html#sec-%foriniteratorprototype%-object">%ForInIteratorPrototype%</a></emu-xref>, « <var class="field">[[Object]]</var>, <var class="field">[[ObjectWasVisited]]</var>, <var class="field">[[VisitedKeys]]</var>, <var class="field">[[RemainingKeys]]</var> »).</li><li>Set <var>iterator</var>.<var class="field">[[Object]]</var> to <var>object</var>.</li><li>Set <var>iterator</var>.<var class="field">[[ObjectWasVisited]]</var> to <emu-val>false</emu-val>.</li><li>Set <var>iterator</var>.<var class="field">[[VisitedKeys]]</var> to a new empty <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7059"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref>.</li><li>Set <var>iterator</var>.<var class="field">[[RemainingKeys]]</var> to a new empty <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7060"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref>.</li><li>Return <var>iterator</var>.</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-%foriniteratorprototype%-object"> <h1>14.7.5.10.2 The %ForInIteratorPrototype% Object</h1> The <dfn tabindex="-1">%ForInIteratorPrototype%</dfn> object: <ul> <li>has properties that are inherited by all <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7061"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator objects</a></emu-xref>.</li> <li>is an <emu-xref href="#ordinary-object" id="_ref_7062"><a href="ecmascript-data-types-and-values.html#ordinary-object">ordinary object</a></emu-xref>.</li> <li>has a <var class="field">[[Prototype]]</var> internal slot whose value is <emu-xref href="#sec-%iterator.prototype%-object" id="_ref_7063"><a href="control-abstraction-objects.html#sec-%iterator.prototype%-object">%Iterator.prototype%</a></emu-xref>.</li> <li>is never directly accessible to ECMAScript code.</li> <li>has the following properties:</li> </ul> <emu-clause id="sec-%foriniteratorprototype%.next"> <h1>14.7.5.10.2.1 %ForInIteratorPrototype%.next ( )</h1> <emu-alg><ol><li>Let <var>O</var> be the <emu-val>this</emu-val> value.</li><li><emu-xref href="#assert" id="_ref_7064"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>O</var> <emu-xref href="#sec-object-type" id="_ref_7065"><a href="ecmascript-data-types-and-values.html#sec-object-type">is an Object</a></emu-xref>.</li><li><emu-xref href="#assert" id="_ref_7066"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>O</var> has all of the internal slots of a <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7067"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator</a></emu-xref> Instance (<emu-xref href="#sec-properties-of-for-in-iterator-instances" id="_ref_452"><a href="ecmascript-language-statements-and-declarations.html#sec-properties-of-for-in-iterator-instances">14.7.5.10.3</a></emu-xref>).</li><li>Let <var>object</var> be <var>O</var>.<var class="field">[[Object]]</var>.</li><li>Repeat,<ol><li>If <var>O</var>.<var class="field">[[ObjectWasVisited]]</var> is <emu-val>false</emu-val>, then<ol><li>Let <var>keys</var> be ? <var>object</var>.<var class="field">[[OwnPropertyKeys]]</var>().</li><li>For each element <var>key</var> of <var>keys</var>, do<ol><li>If <var>key</var> <emu-xref href="#sec-ecmascript-language-types-string-type" id="_ref_7068"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types-string-type">is a String</a></emu-xref>, then<ol><li>Append <var>key</var> to <var>O</var>.<var class="field">[[RemainingKeys]]</var>.</li></ol></li></ol></li><li>Set <var>O</var>.<var class="field">[[ObjectWasVisited]]</var> to <emu-val>true</emu-val>.</li></ol></li><li>Repeat, while <var>O</var>.<var class="field">[[RemainingKeys]]</var> is not empty,<ol><li>Let <var>r</var> be the first element of <var>O</var>.<var class="field">[[RemainingKeys]]</var>.</li><li>Remove the first element from <var>O</var>.<var class="field">[[RemainingKeys]]</var>.</li><li>If <var>O</var>.<var class="field">[[VisitedKeys]]</var> does not contain <var>r</var>, then<ol><li>Let <var>desc</var> be ? <var>object</var>.<var class="field">[[GetOwnProperty]]</var>(<var>r</var>).</li><li>If <var>desc</var> is not <emu-val>undefined</emu-val>, then<ol><li>Append <var>r</var> to <var>O</var>.<var class="field">[[VisitedKeys]]</var>.</li><li>If <var>desc</var>.<var class="field">[[Enumerable]]</var> is <emu-val>true</emu-val>, return <emu-xref aoid="CreateIteratorResultObject" id="_ref_7069"><a href="abstract-operations.html#sec-createiterresultobject">CreateIteratorResultObject</a></emu-xref>(<var>r</var>, <emu-val>false</emu-val>).</li></ol></li></ol></li></ol></li><li>Set <var>object</var> to ? <var>object</var>.<var class="field">[[GetPrototypeOf]]</var>().</li><li>Set <var>O</var>.<var class="field">[[Object]]</var> to <var>object</var>.</li><li>Set <var>O</var>.<var class="field">[[ObjectWasVisited]]</var> to <emu-val>false</emu-val>.</li><li>If <var>object</var> is <emu-val>null</emu-val>, return <emu-xref aoid="CreateIteratorResultObject" id="_ref_7070"><a href="abstract-operations.html#sec-createiterresultobject">CreateIteratorResultObject</a></emu-xref>(<emu-val>undefined</emu-val>, <emu-val>true</emu-val>).</li></ol></li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-properties-of-for-in-iterator-instances"> <h1>14.7.5.10.3 Properties of For-In Iterator Instances</h1> <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7071"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator</a></emu-xref> instances are <emu-xref href="#ordinary-object" id="_ref_7072"><a href="ecmascript-data-types-and-values.html#ordinary-object">ordinary objects</a></emu-xref> that inherit properties from the <emu-xref href="#sec-%foriniteratorprototype%-object" id="_ref_7073"><a href="ecmascript-language-statements-and-declarations.html#sec-%foriniteratorprototype%-object">%ForInIteratorPrototype%</a></emu-xref> intrinsic object. <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7074"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator</a></emu-xref> instances are initially created with the internal slots listed in <emu-xref href="#table-for-in-iterator-instance-slots" id="_ref_453"><a href="ecmascript-language-statements-and-declarations.html#table-for-in-iterator-instance-slots">Table 38</a></emu-xref>. <emu-table id="table-for-in-iterator-instance-slots" caption="Internal Slots of For-In Iterator Instances"><figure><figcaption>Table 38: Internal Slots of <emu-xref href="#sec-for-in-iterator-objects" id="_ref_7075"><a href="ecmascript-language-statements-and-declarations.html#sec-for-in-iterator-objects">For-In Iterator</a></emu-xref> Instances</figcaption> <table> <thead> <tr> <th> Internal Slot </th> <th> Type </th> <th> Description </th> </tr> </thead> <tbody><tr> <td> <var class="field">[[Object]]</var> </td> <td> an Object </td> <td> The Object value whose properties are being iterated. </td> </tr> <tr> <td> <var class="field">[[ObjectWasVisited]]</var> </td> <td> a Boolean </td> <td> <emu-val>true</emu-val> if the <emu-xref href="#sec-iterator-interface" id="_ref_7076"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref> has invoked <var class="field">[[OwnPropertyKeys]]</var> on <var class="field">[[Object]]</var>, <emu-val>false</emu-val> otherwise. </td> </tr> <tr> <td> <var class="field">[[VisitedKeys]]</var> </td> <td> a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7077"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings </td> <td> The values that have been emitted by this <emu-xref href="#sec-iterator-interface" id="_ref_7078"><a href="control-abstraction-objects.html#sec-iterator-interface">iterator</a></emu-xref> thus far. </td> </tr> <tr> <td> <var class="field">[[RemainingKeys]]</var> </td> <td> a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7079"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings </td> <td> The values remaining to be emitted for the current object, before iterating the properties of its prototype (if its prototype is not <emu-val>null</emu-val>). </td> </tr> </tbody></table> </figure></emu-table> </emu-clause> </emu-clause> </emu-clause> </emu-clause> <emu-clause id="sec-continue-statement"> <h1>14.8 The <code>continue</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="ContinueStatement" params="Yield, Await" id="prod-ContinueStatement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="6qppgxyk" id="prod-rfM2mnQY"> <emu-t>continue</emu-t> <emu-t>;</emu-t> </emu-rhs> <emu-rhs a="fiwlh1nt" id="prod-w6m19zWs"> <emu-t>continue</emu-t> <emu-gann>[no <emu-nt id="_ref_20776"><a href="ecmascript-language-lexical-grammar.html#prod-LineTerminator">LineTerminator</a></emu-nt> here]</emu-gann> <emu-nt params="?Yield, ?Await" id="_ref_20777"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-continue-statement-static-semantics-early-errors"> <h1>14.8.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="ContinueStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="6qppgxyk"> <emu-t>continue</emu-t> <emu-t>;</emu-t> </emu-rhs> <emu-rhs a="wh7qddgu"> <emu-t>continue</emu-t> <emu-nt id="_ref_20778"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if this <emu-nt id="_ref_20779"><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a></emu-nt> is not nested, directly or indirectly (but not crossing function or <code>static</code> initialization block boundaries), within an <emu-nt id="_ref_20780"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt>. </li> </ul> </emu-clause> <emu-clause id="sec-continue-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.8.2 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="ContinueStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="6qppgxyk" id="prod-MdaDQGie"> <emu-t>continue</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-xref href="#sec-completion-record-specification-type" id="_ref_7080"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> { <var class="field">[[Type]]</var>: <emu-const>continue</emu-const>, <var class="field">[[Value]]</var>: <emu-const>empty</emu-const>, <var class="field">[[Target]]</var>: <emu-const>empty</emu-const> }.</li></ol></emu-alg> <emu-grammar><emu-production name="ContinueStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="wh7qddgu" id="prod-sLmRG5Rx"> <emu-t>continue</emu-t> <emu-nt id="_ref_20781"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>label</var> be the <emu-xref aoid="StringValue" id="_ref_7081"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20782"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt>.</li><li>Return <emu-xref href="#sec-completion-record-specification-type" id="_ref_7082"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> { <var class="field">[[Type]]</var>: <emu-const>continue</emu-const>, <var class="field">[[Value]]</var>: <emu-const>empty</emu-const>, <var class="field">[[Target]]</var>: <var>label</var> }.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-break-statement"> <h1>14.9 The <code>break</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="BreakStatement" params="Yield, Await" id="prod-BreakStatement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="tlip5zkt" id="prod-Jyx4vreG"> <emu-t>break</emu-t> <emu-t>;</emu-t> </emu-rhs> <emu-rhs a="nio0l2c9" id="prod-_aoH2Ltk"> <emu-t>break</emu-t> <emu-gann>[no <emu-nt id="_ref_20783"><a href="ecmascript-language-lexical-grammar.html#prod-LineTerminator">LineTerminator</a></emu-nt> here]</emu-gann> <emu-nt params="?Yield, ?Await" id="_ref_20784"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-break-statement-static-semantics-early-errors"> <h1>14.9.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="BreakStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="tlip5zkt"> <emu-t>break</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if this <emu-nt id="_ref_20785"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a></emu-nt> is not nested, directly or indirectly (but not crossing function or <code>static</code> initialization block boundaries), within an <emu-nt id="_ref_20786"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> or a <emu-nt id="_ref_20787"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt>. </li> </ul> </emu-clause> <emu-clause id="sec-break-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.9.2 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="BreakStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="tlip5zkt" id="prod-0ioO2qvc"> <emu-t>break</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-xref href="#sec-completion-record-specification-type" id="_ref_7083"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> { <var class="field">[[Type]]</var>: <emu-const>break</emu-const>, <var class="field">[[Value]]</var>: <emu-const>empty</emu-const>, <var class="field">[[Target]]</var>: <emu-const>empty</emu-const> }.</li></ol></emu-alg> <emu-grammar><emu-production name="BreakStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="kcg-yy3r" id="prod-eokV1qEw"> <emu-t>break</emu-t> <emu-nt id="_ref_20788"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>label</var> be the <emu-xref aoid="StringValue" id="_ref_7084"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20789"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt>.</li><li>Return <emu-xref href="#sec-completion-record-specification-type" id="_ref_7085"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> { <var class="field">[[Type]]</var>: <emu-const>break</emu-const>, <var class="field">[[Value]]</var>: <emu-const>empty</emu-const>, <var class="field">[[Target]]</var>: <var>label</var> }.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-return-statement"> <h1>14.10 The <code>return</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="ReturnStatement" params="Yield, Await" id="prod-ReturnStatement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ReturnStatement">ReturnStatement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="cykzgrgr" id="prod-zZYaGxQ8"> <emu-t>return</emu-t> <emu-t>;</emu-t> </emu-rhs> <emu-rhs a="tybfdyhl" id="prod-TbDZIC37"> <emu-t>return</emu-t> <emu-gann>[no <emu-nt id="_ref_20790"><a href="ecmascript-language-lexical-grammar.html#prod-LineTerminator">LineTerminator</a></emu-nt> here]</emu-gann> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20791"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note<div class="note-contents"> A <code>return</code> statement causes a function to cease execution and, in most cases, returns a value to the caller. If <emu-nt id="_ref_20792"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> is omitted, the return value is <emu-val>undefined</emu-val>. Otherwise, the return value is the value of <emu-nt id="_ref_20793"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>. A <code>return</code> statement may not actually return a value to the caller depending on surrounding context. For example, in a <code>try</code> block, a <code>return</code> statement's <emu-xref href="#sec-completion-record-specification-type" id="_ref_7086"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> may be replaced with another <emu-xref href="#sec-completion-record-specification-type" id="_ref_7087"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref> during evaluation of the <code>finally</code> block. </div></emu-note> <emu-clause id="sec-return-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.10.1 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="ReturnStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ReturnStatement">ReturnStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="cykzgrgr" id="prod-G_yzzAkQ"> <emu-t>return</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-xref aoid="ReturnCompletion" id="_ref_7088"><a href="ecmascript-data-types-and-values.html#sec-returncompletion">ReturnCompletion</a></emu-xref>(<emu-val>undefined</emu-val>).</li></ol></emu-alg> <emu-grammar><emu-production name="ReturnStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ReturnStatement">ReturnStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="tpdzx2lh" id="prod-iroo5DiR"> <emu-t>return</emu-t> <emu-nt id="_ref_20794"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_7089"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20795"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>exprValue</var> be ? <emu-xref aoid="GetValue" id="_ref_7090"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li><li>If <emu-xref aoid="GetGeneratorKind" id="_ref_7091"><a href="control-abstraction-objects.html#sec-getgeneratorkind">GetGeneratorKind</a></emu-xref>() is <emu-const>async</emu-const>, set <var>exprValue</var> to ? <emu-xref aoid="Await" id="_ref_7092"><a href="control-abstraction-objects.html#await" class="e-user-code">Await</a></emu-xref>(<var>exprValue</var>).</li><li>Return <emu-xref aoid="ReturnCompletion" id="_ref_7093"><a href="ecmascript-data-types-and-values.html#sec-returncompletion">ReturnCompletion</a></emu-xref>(<var>exprValue</var>).</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-with-statement" legacy=""><div class="attributes-tag"><emu-xref href="#sec-conformance" id="_ref_7112"><a href="conformance.html#sec-conformance">Legacy</a></emu-xref></div> <h1>14.11 The <code>with</code> Statement</h1> <emu-note>Note 1<div class="note-contents"> Use of the <emu-xref href="#sec-conformance" id="_ref_7094"><a href="conformance.html#sec-conformance">Legacy</a></emu-xref> <code>with</code> statement is discouraged in new ECMAScript code. Consider alternatives that are permitted in both <emu-xref href="#sec-strict-mode-code" id="_ref_7095"><a href="ecmascript-language-source-code.html#sec-strict-mode-code">strict mode code</a></emu-xref> and <emu-xref href="#non-strict-code" id="_ref_7096"><a href="ecmascript-language-source-code.html#non-strict-code">non-strict code</a></emu-xref>, such as <emu-xref href="#sec-destructuring-assignment" id="_ref_454"><a href="ecmascript-language-expressions.html#sec-destructuring-assignment">destructuring assignment</a></emu-xref>. </div></emu-note> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="WithStatement" params="Yield, Await, Return" id="prod-WithStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-WithStatement">WithStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="lo7bccts" id="prod-3HlNX-pI"> <emu-t>with</emu-t> <emu-t>(</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20796"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20797"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note 2<div class="note-contents"> The <code>with</code> statement adds an <emu-xref href="#sec-object-environment-records" id="_ref_7097"><a href="executable-code-and-execution-contexts.html#sec-object-environment-records">Object Environment Record</a></emu-xref> for a computed object to the lexical environment of the <emu-xref href="#running-execution-context" id="_ref_7098"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>. It then executes a statement using this augmented lexical environment. Finally, it restores the original lexical environment. </div></emu-note> <emu-clause id="sec-with-statement-static-semantics-early-errors"> <h1>14.11.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="WithStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-WithStatement">WithStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="i70kview"> <emu-t>with</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20798"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20799"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if <emu-xref aoid="IsStrict" id="_ref_7099"><a href="ecmascript-language-source-code.html#sec-isstrict">IsStrict</a></emu-xref>(this production) is <emu-val>true</emu-val>. </li> <li> It is a Syntax Error if <emu-xref aoid="IsLabelledFunction" id="_ref_7100"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<emu-nt id="_ref_20800"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>) is <emu-val>true</emu-val>. </li> </ul> <emu-note>Note<div class="note-contents"> It is only necessary to apply the second rule if the extension specified in <emu-xref href="#sec-labelled-function-declarations" id="_ref_455"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref> is implemented. </div></emu-note> </emu-clause> <emu-clause id="sec-with-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.11.2 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="WithStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-WithStatement">WithStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="i70kview" id="prod-OowrNhmq"> <emu-t>with</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20801"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20802"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>val</var> be ? <emu-xref aoid="Evaluation" id="_ref_7101"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20803"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>obj</var> be ? <emu-xref aoid="ToObject" id="_ref_7102"><a href="abstract-operations.html#sec-toobject">ToObject</a></emu-xref>(? <emu-xref aoid="GetValue" id="_ref_7103"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>val</var>)).</li><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_7104"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>newEnv</var> be <emu-xref aoid="NewObjectEnvironment" id="_ref_7105"><a href="executable-code-and-execution-contexts.html#sec-newobjectenvironment">NewObjectEnvironment</a></emu-xref>(<var>obj</var>, <emu-val>true</emu-val>, <var>oldEnv</var>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7106"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>newEnv</var>.</li><li>Let <var>C</var> be <emu-xref aoid="Completion" id="_ref_7107"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7108"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20804"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7109"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_7110"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>C</var>, <emu-val>undefined</emu-val>).</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> No matter how control leaves the embedded <emu-nt id="_ref_20805"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>, whether normally or by some form of <emu-xref href="#sec-completion-record-specification-type" id="_ref_7111"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref> or exception, the LexicalEnvironment is always restored to its former state. </div></emu-note> </emu-clause> </emu-clause> <emu-clause id="sec-switch-statement"> <h1>14.12 The <code>switch</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="SwitchStatement" params="Yield, Await, Return" id="prod-SwitchStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="drlywp4w" id="prod-3xRnqKfC"> <emu-t>switch</emu-t> <emu-t>(</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20806"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20807"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="CaseBlock" params="Yield, Await, Return" id="prod-CaseBlock"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="v-h2atfk" id="prod-q66ZlOHI"> <emu-t>{</emu-t> <emu-nt params="?Yield, ?Await, ?Return" optional="" id="_ref_20808"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> <emu-rhs a="00sitdqr" id="prod-JuWwIrcZ"> <emu-t>{</emu-t> <emu-nt params="?Yield, ?Await, ?Return" optional="" id="_ref_20809"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20810"><a href="ecmascript-language-statements-and-declarations.html#prod-DefaultClause">DefaultClause</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" optional="" id="_ref_20811"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> <emu-production name="CaseClauses" params="Yield, Await, Return" id="prod-CaseClauses"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="xpjvtgza"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20812"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="8r6dchoz" id="prod-sjZo1Z65"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20813"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20814"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="CaseClause" params="Yield, Await, Return" id="prod-CaseClause"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="zpq23qtn" id="prod-A-5Q_6I5"> <emu-t>case</emu-t> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20815"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>:</emu-t> <emu-nt params="?Yield, ?Await, ?Return" optional="" id="_ref_20816"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="DefaultClause" params="Yield, Await, Return" id="prod-DefaultClause"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-DefaultClause">DefaultClause</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="djnlaxcj" id="prod-HPF3iA_C"> <emu-t>default</emu-t> <emu-t>:</emu-t> <emu-nt params="?Yield, ?Await, ?Return" optional="" id="_ref_20817"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-switch-statement-static-semantics-early-errors"> <h1>14.12.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="SwitchStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uvrp_hkw"> <emu-t>switch</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20818"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20819"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if the <emu-xref aoid="LexicallyDeclaredNames" id="_ref_7113"><a href="syntax-directed-operations.html#sec-static-semantics-lexicallydeclarednames">LexicallyDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20820"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> contains any duplicate entries. </li> <li> It is a Syntax Error if any element of the <emu-xref aoid="LexicallyDeclaredNames" id="_ref_7114"><a href="syntax-directed-operations.html#sec-static-semantics-lexicallydeclarednames">LexicallyDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20821"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> also occurs in the <emu-xref aoid="VarDeclaredNames" id="_ref_7115"><a href="syntax-directed-operations.html#sec-static-semantics-vardeclarednames">VarDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20822"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt>. </li> </ul> </emu-clause> <emu-clause id="sec-runtime-semantics-caseblockevaluation" type="sdo" aoid="CaseBlockEvaluation"> <h1>14.12.2 Runtime Semantics: CaseBlockEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_7116"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> CaseBlockEvaluation takes argument <var>input</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_7117"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7118"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> an <emu-xref href="#sec-ecmascript-language-types" id="_ref_7119"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7120"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="CaseBlock" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gbpaspne" id="prod--oXyocga"> <emu-t>{</emu-t> <emu-t>}</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-val>undefined</emu-val>.</li></ol></emu-alg> <emu-grammar><emu-production name="CaseBlock" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="eerblgqb" id="prod-n6COrqbY"> <emu-t>{</emu-t> <emu-nt id="_ref_20823"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>V</var> be <emu-val>undefined</emu-val>.</li><li>Let <var>A</var> be the <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7121"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of <emu-nt id="_ref_20824"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> items in <emu-nt id="_ref_20825"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt>, in source text order.</li><li>Let <var>found</var> be <emu-val>false</emu-val>.</li><li>For each <emu-nt id="_ref_20826"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <var>C</var> of <var>A</var>, do<ol><li>If <var>found</var> is <emu-val>false</emu-val>, then<ol><li>Set <var>found</var> to ? <emu-xref aoid="CaseClauseIsSelected" id="_ref_7122"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-caseclauseisselected" class="e-user-code">CaseClauseIsSelected</a></emu-xref>(<var>C</var>, <var>input</var>).</li></ol></li><li>If <var>found</var> is <emu-val>true</emu-val>, then<ol><li>Let <var>R</var> be <emu-xref aoid="Completion" id="_ref_7123"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7124"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>C</var>).</li><li>If <var>R</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>R</var>.<var class="field">[[Value]]</var>.</li><li>If <var>R</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7125"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_7126"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>R</var>, <var>V</var>).</li></ol></li></ol></li><li>Return <var>V</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="CaseBlock" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ududlhou" id="prod-bc5B_Aaw"> <emu-t>{</emu-t> <emu-nt optional="" id="_ref_20827"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-nt id="_ref_20828"><a href="ecmascript-language-statements-and-declarations.html#prod-DefaultClause">DefaultClause</a></emu-nt> <emu-nt optional="" id="_ref_20829"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> <emu-t>}</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>V</var> be <emu-val>undefined</emu-val>.</li><li>If the first <emu-nt id="_ref_20830"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt> is present, then<ol><li>Let <var>A</var> be the <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7127"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of <emu-nt id="_ref_20831"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> items in the first <emu-nt id="_ref_20832"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt>, in source text order.</li></ol></li><li>Else,<ol><li>Let <var>A</var> be a new empty <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7128"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref>.</li></ol></li><li>Let <var>found</var> be <emu-val>false</emu-val>.</li><li>For each <emu-nt id="_ref_20833"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <var>C</var> of <var>A</var>, do<ol><li>If <var>found</var> is <emu-val>false</emu-val>, then<ol><li>Set <var>found</var> to ? <emu-xref aoid="CaseClauseIsSelected" id="_ref_7129"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-caseclauseisselected" class="e-user-code">CaseClauseIsSelected</a></emu-xref>(<var>C</var>, <var>input</var>).</li></ol></li><li>If <var>found</var> is <emu-val>true</emu-val>, then<ol><li>Let <var>R</var> be <emu-xref aoid="Completion" id="_ref_7130"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7131"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <var>C</var>).</li><li>If <var>R</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>R</var>.<var class="field">[[Value]]</var>.</li><li>If <var>R</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7132"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_7133"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>R</var>, <var>V</var>).</li></ol></li></ol></li><li>Let <var>foundInB</var> be <emu-val>false</emu-val>.</li><li>If the second <emu-nt id="_ref_20834"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt> is present, then<ol><li>Let <var>B</var> be the <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7134"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of <emu-nt id="_ref_20835"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> items in the second <emu-nt id="_ref_20836"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt>, in source text order.</li></ol></li><li>Else,<ol><li>Let <var>B</var> be a new empty <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7135"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref>.</li></ol></li><li>If <var>found</var> is <emu-val>false</emu-val>, then<ol><li>For each <emu-nt id="_ref_20837"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <var>C</var> of <var>B</var>, do<ol><li>If <var>foundInB</var> is <emu-val>false</emu-val>, then<ol><li>Set <var>foundInB</var> to ? <emu-xref aoid="CaseClauseIsSelected" id="_ref_7136"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-caseclauseisselected" class="e-user-code">CaseClauseIsSelected</a></emu-xref>(<var>C</var>, <var>input</var>).</li></ol></li><li>If <var>foundInB</var> is <emu-val>true</emu-val>, then<ol><li>Let <var>R</var> be <emu-xref aoid="Completion" id="_ref_7137"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7138"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20838"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <var>C</var>).</li><li>If <var>R</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>R</var>.<var class="field">[[Value]]</var>.</li><li>If <var>R</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7139"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_7140"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>R</var>, <var>V</var>).</li></ol></li></ol></li></ol></li><li>If <var>foundInB</var> is <emu-val>true</emu-val>, return <var>V</var>.</li><li>Let <var>defaultR</var> be <emu-xref aoid="Completion" id="_ref_7141"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7142"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20839"><a href="ecmascript-language-statements-and-declarations.html#prod-DefaultClause">DefaultClause</a></emu-nt>).</li><li>If <var>defaultR</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>defaultR</var>.<var class="field">[[Value]]</var>.</li><li>If <var>defaultR</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7143"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_7144"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>defaultR</var>, <var>V</var>).</li><li>NOTE: The following is another complete iteration of the second <emu-nt id="_ref_20840"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClauses">CaseClauses</a></emu-nt>.</li><li>For each <emu-nt id="_ref_20841"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <var>C</var> of <var>B</var>, do<ol><li>Let <var>R</var> be <emu-xref aoid="Completion" id="_ref_7145"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7146"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20842"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <var>C</var>).</li><li>If <var>R</var>.<var class="field">[[Value]]</var> is not <emu-const>empty</emu-const>, set <var>V</var> to <var>R</var>.<var class="field">[[Value]]</var>.</li><li>If <var>R</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7147"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, return ? <emu-xref aoid="UpdateEmpty" id="_ref_7148"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>R</var>, <var>V</var>).</li></ol></li><li>Return <var>V</var>.</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-runtime-semantics-caseclauseisselected" type="abstract operation" oldids="sec-runtime-semantics-caseselectorevaluation" aoid="CaseClauseIsSelected"> <h1>14.12.3 CaseClauseIsSelected ( <var>C</var>, <var>input</var> )</h1> The abstract operation CaseClauseIsSelected takes arguments <var>C</var> (a <emu-nt id="_ref_20843"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_7149"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>) and <var>input</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_7150"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7151"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> a Boolean or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7152"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It determines whether <var>C</var> matches <var>input</var>. It performs the following steps when called: <emu-alg><ol><li><emu-xref href="#assert" id="_ref_7153"><a href="notational-conventions.html#assert">Assert</a></emu-xref>: <var>C</var> is an instance of the production <emu-grammar><emu-production name="CaseClause" collapsed="" class=" inline"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="x20nmjyd"> <emu-t>case</emu-t> <emu-nt id="_ref_20844"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>:</emu-t> <emu-nt optional="" id="_ref_20845"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a><emu-mods><emu-opt>opt</emu-opt></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar>.</li><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_7154"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of the <emu-nt id="_ref_20846"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> of <var>C</var>.</li><li>Let <var>clauseSelector</var> be ? <emu-xref aoid="GetValue" id="_ref_7155"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li><li>Return <emu-xref aoid="IsStrictlyEqual" id="_ref_7156"><a href="abstract-operations.html#sec-isstrictlyequal">IsStrictlyEqual</a></emu-xref>(<var>input</var>, <var>clauseSelector</var>).</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> This operation does not execute <var>C</var>'s <emu-nt id="_ref_20847"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> (if any). The <emu-nt id="_ref_20848"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> algorithm uses its return value to determine which <emu-nt id="_ref_20849"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> to start executing. </div></emu-note> </emu-clause> <emu-clause id="sec-switch-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.12.4 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="SwitchStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="uvrp_hkw" id="prod-raA0Z_ll"> <emu-t>switch</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20850"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20851"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_7157"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20852"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>switchValue</var> be ? <emu-xref aoid="GetValue" id="_ref_7158"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_7159"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>blockEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_7160"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>oldEnv</var>).</li><li>Perform <emu-xref aoid="BlockDeclarationInstantiation" id="_ref_7161"><a href="ecmascript-language-statements-and-declarations.html#sec-blockdeclarationinstantiation">BlockDeclarationInstantiation</a></emu-xref>(<emu-nt id="_ref_20853"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt>, <var>blockEnv</var>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7162"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>blockEnv</var>.</li><li>Let <var>R</var> be <emu-xref aoid="Completion" id="_ref_7163"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="CaseBlockEvaluation" id="_ref_7164"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-caseblockevaluation" class="e-user-code">CaseBlockEvaluation</a></emu-xref> of <emu-nt id="_ref_20854"><a href="ecmascript-language-statements-and-declarations.html#prod-CaseBlock">CaseBlock</a></emu-nt> with argument <var>switchValue</var>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7165"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return <var>R</var>.</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> No matter how control leaves the <emu-nt id="_ref_20855"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt> the LexicalEnvironment is always restored to its former state. </div></emu-note> <emu-grammar><emu-production name="CaseClause" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="amgxmkjg" id="prod-pfa8PeiE"> <emu-t>case</emu-t> <emu-nt id="_ref_20856"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>:</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="CaseClause" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-CaseClause">CaseClause</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="eencdyk7" id="prod-SiRXsnRx"> <emu-t>case</emu-t> <emu-nt id="_ref_20857"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>:</emu-t> <emu-nt id="_ref_20858"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="Evaluation" id="_ref_7166"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20859"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>.</li></ol></emu-alg> <emu-grammar><emu-production name="DefaultClause" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-DefaultClause">DefaultClause</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="t5rjsefq" id="prod-f0Rq5Irs"> <emu-t>default</emu-t> <emu-t>:</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return <emu-const>empty</emu-const>.</li></ol></emu-alg> <emu-grammar><emu-production name="DefaultClause" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-DefaultClause">DefaultClause</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="odaivkwk" id="prod-eOryVE-Y"> <emu-t>default</emu-t> <emu-t>:</emu-t> <emu-nt id="_ref_20860"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="Evaluation" id="_ref_7167"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20861"><a href="ecmascript-language-statements-and-declarations.html#prod-StatementList">StatementList</a></emu-nt>.</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-labelled-statements"> <h1>14.13 Labelled Statements</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="LabelledStatement" params="Yield, Await, Return" id="prod-LabelledStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="vhxkapdt" id="prod-0GG8m5VC"> <emu-nt params="?Yield, ?Await" id="_ref_20862"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>:</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20863"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="LabelledItem" params="Yield, Await, Return" id="prod-LabelledItem"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="septp5sa" id="prod-YaWmIZ1c"> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20864"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="d0nwjyav" id="prod-GPTeOVBJ"> <emu-nt params="?Yield, ?Await, ~Default" id="_ref_20865"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a><emu-mods><emu-params>[?Yield, ?Await, ~Default]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note<div class="note-contents"> A <emu-nt id="_ref_20866"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> may be prefixed by a label. Labelled statements are only used in conjunction with labelled <code>break</code> and <code>continue</code> statements. ECMAScript has no <code>goto</code> statement. A <emu-nt id="_ref_20867"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> can be part of a <emu-nt id="_ref_20868"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt>, which itself can be part of a <emu-nt id="_ref_20869"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt>, and so on. The labels introduced this way are collectively referred to as the “current label set” when describing the semantics of individual statements. </div></emu-note> <emu-clause id="sec-labelled-statements-static-semantics-early-errors"> <h1>14.13.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="LabelledItem" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="-nqupnlb"><emu-nt id="_ref_20870"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if any source text is matched by this production. </li> </ul> <emu-note>Note<div class="note-contents"> An alternative definition for this rule is provided in <emu-xref href="#sec-labelled-function-declarations" id="_ref_456"><a href="additional-ecmascript-features-for-web-browsers.html#sec-labelled-function-declarations">B.3.1</a></emu-xref>. </div></emu-note> </emu-clause> <emu-clause id="sec-islabelledfunction" type="abstract operation" aoid="IsLabelledFunction"> <h1>14.13.2 Static Semantics: IsLabelledFunction ( <var>stmt</var> )</h1> The abstract operation IsLabelledFunction takes argument <var>stmt</var> (a <emu-nt id="_ref_20871"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-xref href="#sec-syntactic-grammar" id="_ref_7168"><a href="notational-conventions.html#sec-syntactic-grammar">Parse Node</a></emu-xref>) and returns a Boolean. It performs the following steps when called: <emu-alg><ol><li>If <var>stmt</var> is not a <emu-nt id="_ref_20872"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt>, return <emu-val>false</emu-val>.</li><li>Let <var>item</var> be the <emu-nt id="_ref_20873"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> of <var>stmt</var>.</li><li>If <var>item</var> is <emu-grammar><emu-production name="LabelledItem" collapsed="" class=" inline"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="-nqupnlb"><emu-nt id="_ref_20874"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt></emu-rhs> </emu-production> </emu-grammar>, return <emu-val>true</emu-val>.</li><li>Let <var>subStmt</var> be the <emu-nt id="_ref_20875"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> of <var>item</var>.</li><li>Return <emu-xref aoid="IsLabelledFunction" id="_ref_7169"><a href="ecmascript-language-statements-and-declarations.html#sec-islabelledfunction">IsLabelledFunction</a></emu-xref>(<var>subStmt</var>).</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-labelled-statements-runtime-semantics-evaluation" type="sdo"> <h1>14.13.3 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="LabelledStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ubbvtbun" id="prod-z6MMrwO3"> <emu-nt id="_ref_20876"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt> <emu-t>:</emu-t> <emu-nt id="_ref_20877"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="LabelledEvaluation" id="_ref_7170"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-labelledevaluation" class="e-user-code">LabelledEvaluation</a></emu-xref> of this <emu-nt id="_ref_20878"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt> with argument « ».</li></ol></emu-alg> </emu-clause> <emu-clause id="sec-runtime-semantics-labelledevaluation" oldids="sec-statement-semantics-runtime-semantics-labelledevaluation,sec-labelled-statements-runtime-semantics-labelledevaluation" type="sdo" aoid="LabelledEvaluation"> <h1>14.13.4 Runtime Semantics: LabelledEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_7171"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> LabelledEvaluation takes argument <var>labelSet</var> (a <emu-xref href="#sec-list-and-record-specification-type" id="_ref_7172"><a href="ecmascript-data-types-and-values.html#sec-list-and-record-specification-type">List</a></emu-xref> of Strings) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7173"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> either an <emu-xref href="#sec-ecmascript-language-types" id="_ref_7174"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or <emu-const>empty</emu-const>, or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7175"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="BreakableStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="kmxl4yum" id="prod-pR7DNQsN"><emu-nt id="_ref_20879"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>stmtResult</var> be <emu-xref aoid="Completion" id="_ref_7176"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="LoopEvaluation" id="_ref_7177"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-loopevaluation" class="e-user-code">LoopEvaluation</a></emu-xref> of <emu-nt id="_ref_20880"><a href="ecmascript-language-statements-and-declarations.html#prod-IterationStatement">IterationStatement</a></emu-nt> with argument <var>labelSet</var>).</li><li>If <var>stmtResult</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7178"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">break completion</a></emu-xref>, then<ol><li>If <var>stmtResult</var>.<var class="field">[[Target]]</var> is <emu-const>empty</emu-const>, then<ol><li>If <var>stmtResult</var>.<var class="field">[[Value]]</var> is <emu-const>empty</emu-const>, set <var>stmtResult</var> to <emu-xref aoid="NormalCompletion" id="_ref_7179"><a href="ecmascript-data-types-and-values.html#sec-normalcompletion">NormalCompletion</a></emu-xref>(<emu-val>undefined</emu-val>).</li><li>Else, set <var>stmtResult</var> to <emu-xref aoid="NormalCompletion" id="_ref_7180"><a href="ecmascript-data-types-and-values.html#sec-normalcompletion">NormalCompletion</a></emu-xref>(<var>stmtResult</var>.<var class="field">[[Value]]</var>).</li></ol></li></ol></li><li>Return ? <var>stmtResult</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="BreakableStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="nuio-xfp" id="prod-FSHcHfYw"><emu-nt id="_ref_20881"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>stmtResult</var> be <emu-xref aoid="Completion" id="_ref_7181"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7182"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20882"><a href="ecmascript-language-statements-and-declarations.html#prod-SwitchStatement">SwitchStatement</a></emu-nt>).</li><li>If <var>stmtResult</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7183"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">break completion</a></emu-xref>, then<ol><li>If <var>stmtResult</var>.<var class="field">[[Target]]</var> is <emu-const>empty</emu-const>, then<ol><li>If <var>stmtResult</var>.<var class="field">[[Value]]</var> is <emu-const>empty</emu-const>, set <var>stmtResult</var> to <emu-xref aoid="NormalCompletion" id="_ref_7184"><a href="ecmascript-data-types-and-values.html#sec-normalcompletion">NormalCompletion</a></emu-xref>(<emu-val>undefined</emu-val>).</li><li>Else, set <var>stmtResult</var> to <emu-xref aoid="NormalCompletion" id="_ref_7185"><a href="ecmascript-data-types-and-values.html#sec-normalcompletion">NormalCompletion</a></emu-xref>(<var>stmtResult</var>.<var class="field">[[Value]]</var>).</li></ol></li></ol></li><li>Return ? <var>stmtResult</var>.</li></ol></emu-alg> <emu-note>Note 1<div class="note-contents"> A <emu-nt id="_ref_20883"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a></emu-nt> is one that can be exited via an unlabelled <emu-nt id="_ref_20884"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a></emu-nt>. </div></emu-note> <emu-grammar><emu-production name="LabelledStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ubbvtbun" id="prod-GnWrgP5w"> <emu-nt id="_ref_20885"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt> <emu-t>:</emu-t> <emu-nt id="_ref_20886"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>label</var> be the <emu-xref aoid="StringValue" id="_ref_7186"><a href="ecmascript-language-expressions.html#sec-static-semantics-stringvalue">StringValue</a></emu-xref> of <emu-nt id="_ref_20887"><a href="ecmascript-language-expressions.html#prod-LabelIdentifier">LabelIdentifier</a></emu-nt>.</li><li>Let <var>newLabelSet</var> be the <emu-xref href="#list-concatenation" id="_ref_7187"><a href="ecmascript-data-types-and-values.html#list-concatenation">list-concatenation</a></emu-xref> of <var>labelSet</var> and « <var>label</var> ».</li><li>Let <var>stmtResult</var> be <emu-xref aoid="Completion" id="_ref_7188"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="LabelledEvaluation" id="_ref_7189"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-labelledevaluation" class="e-user-code">LabelledEvaluation</a></emu-xref> of <emu-nt id="_ref_20888"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> with argument <var>newLabelSet</var>).</li><li>If <var>stmtResult</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7190"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">break completion</a></emu-xref> and <var>stmtResult</var>.<var class="field">[[Target]]</var> is <var>label</var>, then<ol><li>Set <var>stmtResult</var> to <emu-xref aoid="NormalCompletion" id="_ref_7191"><a href="ecmascript-data-types-and-values.html#sec-normalcompletion">NormalCompletion</a></emu-xref>(<var>stmtResult</var>.<var class="field">[[Value]]</var>).</li></ol></li><li>Return ? <var>stmtResult</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="LabelledItem" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledItem">LabelledItem</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="-nqupnlb" id="prod-3whCJM4e"><emu-nt id="_ref_20889"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt></emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="Evaluation" id="_ref_7192"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20890"><a href="ecmascript-language-functions-and-classes.html#prod-FunctionDeclaration">FunctionDeclaration</a></emu-nt>.</li></ol></emu-alg> <emu-grammar><emu-production name="Statement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gre9qn6e" id="prod-yFnpxPRG"> <emu-nt id="_ref_20891"><a href="ecmascript-language-statements-and-declarations.html#prod-BlockStatement">BlockStatement</a></emu-nt> </emu-rhs> <emu-rhs a="iwwn8atx" id="prod-Ebz5cXwH"> <emu-nt id="_ref_20892"><a href="ecmascript-language-statements-and-declarations.html#prod-VariableStatement">VariableStatement</a></emu-nt> </emu-rhs> <emu-rhs a="cziqu-45" id="prod-qI_HU3XB"> <emu-nt id="_ref_20893"><a href="ecmascript-language-statements-and-declarations.html#prod-EmptyStatement">EmptyStatement</a></emu-nt> </emu-rhs> <emu-rhs a="gsqkt2bv" id="prod-aRwgRfmk"> <emu-nt id="_ref_20894"><a href="ecmascript-language-statements-and-declarations.html#prod-ExpressionStatement">ExpressionStatement</a></emu-nt> </emu-rhs> <emu-rhs a="skawbrez" id="prod-RLprpFgP"> <emu-nt id="_ref_20895"><a href="ecmascript-language-statements-and-declarations.html#prod-IfStatement">IfStatement</a></emu-nt> </emu-rhs> <emu-rhs a="hx0ynljx" id="prod-4r9ecQgz"> <emu-nt id="_ref_20896"><a href="ecmascript-language-statements-and-declarations.html#prod-ContinueStatement">ContinueStatement</a></emu-nt> </emu-rhs> <emu-rhs a="q4uv-sm3" id="prod-VyFRxEGQ"> <emu-nt id="_ref_20897"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakStatement">BreakStatement</a></emu-nt> </emu-rhs> <emu-rhs a="qm95e4wi" id="prod-Hgg1wqRZ"> <emu-nt id="_ref_20898"><a href="ecmascript-language-statements-and-declarations.html#prod-ReturnStatement">ReturnStatement</a></emu-nt> </emu-rhs> <emu-rhs a="ye6wwgts" id="prod-wFzN_sG0"> <emu-nt id="_ref_20899"><a href="ecmascript-language-statements-and-declarations.html#prod-WithStatement">WithStatement</a></emu-nt> </emu-rhs> <emu-rhs a="hntake-o" id="prod-q_qjzdry"> <emu-nt id="_ref_20900"><a href="ecmascript-language-statements-and-declarations.html#prod-ThrowStatement">ThrowStatement</a></emu-nt> </emu-rhs> <emu-rhs a="ex_crokj" id="prod-7PJ339VQ"> <emu-nt id="_ref_20901"><a href="ecmascript-language-statements-and-declarations.html#prod-TryStatement">TryStatement</a></emu-nt> </emu-rhs> <emu-rhs a="iseu28qi" id="prod-O3yX8Gg7"> <emu-nt id="_ref_20902"><a href="ecmascript-language-statements-and-declarations.html#prod-DebuggerStatement">DebuggerStatement</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="Evaluation" id="_ref_7193"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20903"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt>.</li></ol></emu-alg> <emu-note>Note 2<div class="note-contents"> The only two productions of <emu-nt id="_ref_20904"><a href="ecmascript-language-statements-and-declarations.html#prod-Statement">Statement</a></emu-nt> which have special semantics for LabelledEvaluation are <emu-nt id="_ref_20905"><a href="ecmascript-language-statements-and-declarations.html#prod-BreakableStatement">BreakableStatement</a></emu-nt> and <emu-nt id="_ref_20906"><a href="ecmascript-language-statements-and-declarations.html#prod-LabelledStatement">LabelledStatement</a></emu-nt>. </div></emu-note> </emu-clause> </emu-clause> <emu-clause id="sec-throw-statement"> <h1>14.14 The <code>throw</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="ThrowStatement" params="Yield, Await" id="prod-ThrowStatement"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-ThrowStatement">ThrowStatement</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="q_cybpdb" id="prod-E5ckYtCh"> <emu-t>throw</emu-t> <emu-gann>[no <emu-nt id="_ref_20907"><a href="ecmascript-language-lexical-grammar.html#prod-LineTerminator">LineTerminator</a></emu-nt> here]</emu-gann> <emu-nt params="+In, ?Yield, ?Await" id="_ref_20908"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a><emu-mods><emu-params>[+In, ?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-throw-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.14.1 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="ThrowStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-ThrowStatement">ThrowStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="lauy4mhi" id="prod-fEMuit66"> <emu-t>throw</emu-t> <emu-nt id="_ref_20909"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>exprRef</var> be ? <emu-xref aoid="Evaluation" id="_ref_7194"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20910"><a href="ecmascript-language-expressions.html#prod-Expression">Expression</a></emu-nt>.</li><li>Let <var>exprValue</var> be ? <emu-xref aoid="GetValue" id="_ref_7195"><a href="ecmascript-data-types-and-values.html#sec-getvalue" class="e-user-code">GetValue</a></emu-xref>(<var>exprRef</var>).</li><li>Return <emu-xref aoid="ThrowCompletion" id="_ref_7196"><a href="ecmascript-data-types-and-values.html#sec-throwcompletion">ThrowCompletion</a></emu-xref>(<var>exprValue</var>).</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-try-statement"> <h1>14.15 The <code>try</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="TryStatement" params="Yield, Await, Return" id="prod-TryStatement"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-TryStatement">TryStatement</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="eqx7gx8m" id="prod-wD-TPYub"> <emu-t>try</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20911"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20912"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="ayio9dod" id="prod-EYIEedje"> <emu-t>try</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20913"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20914"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="yfzmez3t" id="prod-cfkI0NCS"> <emu-t>try</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20915"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20916"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20917"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="Catch" params="Yield, Await, Return" id="prod-Catch"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gk6mks18" id="prod-IbvHsEaf"> <emu-t>catch</emu-t> <emu-t>(</emu-t> <emu-nt params="?Yield, ?Await" id="_ref_20918"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> <emu-t>)</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20919"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="vi_srlx8" id="prod-ybInUotF"> <emu-t>catch</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20920"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="Finally" params="Yield, Await, Return" id="prod-Finally"> <emu-nt params="Yield, Await, Return"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a><emu-mods><emu-params>[Yield, Await, Return]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="e9akqlxo"> <emu-t>finally</emu-t> <emu-nt params="?Yield, ?Await, ?Return" id="_ref_20921"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a><emu-mods><emu-params>[?Yield, ?Await, ?Return]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> <emu-production name="CatchParameter" params="Yield, Await" id="prod-CatchParameter"> <emu-nt params="Yield, Await"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a><emu-mods><emu-params>[Yield, Await]</emu-params></emu-mods></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ir-rfjfi"> <emu-nt params="?Yield, ?Await" id="_ref_20922"><a href="ecmascript-language-expressions.html#prod-BindingIdentifier">BindingIdentifier</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> <emu-rhs a="nridwfya"> <emu-nt params="?Yield, ?Await" id="_ref_20923"><a href="ecmascript-language-statements-and-declarations.html#prod-BindingPattern">BindingPattern</a><emu-mods><emu-params>[?Yield, ?Await]</emu-params></emu-mods></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-note>Note<div class="note-contents"> The <code>try</code> statement encloses a block of code in which an exceptional condition can occur, such as a runtime error or a <code>throw</code> statement. The <code>catch</code> clause provides the exception-handling code. When a catch clause catches an exception, its <emu-nt id="_ref_20924"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> is bound to that exception. </div></emu-note> <emu-clause id="sec-try-statement-static-semantics-early-errors"> <h1>14.15.1 Static Semantics: Early Errors</h1> <emu-grammar><emu-production name="Catch" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="3ce8nhiw"> <emu-t>catch</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20925"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20926"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <ul> <li> It is a Syntax Error if the <emu-xref aoid="BoundNames" id="_ref_7197"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20927"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> contains any duplicate elements. </li> <li> It is a Syntax Error if any element of the <emu-xref aoid="BoundNames" id="_ref_7198"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20928"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> also occurs in the <emu-xref aoid="LexicallyDeclaredNames" id="_ref_7199"><a href="syntax-directed-operations.html#sec-static-semantics-lexicallydeclarednames">LexicallyDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20929"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>. </li> <li> It is a Syntax Error if any element of the <emu-xref aoid="BoundNames" id="_ref_7200"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20930"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> also occurs in the <emu-xref aoid="VarDeclaredNames" id="_ref_7201"><a href="syntax-directed-operations.html#sec-static-semantics-vardeclarednames">VarDeclaredNames</a></emu-xref> of <emu-nt id="_ref_20931"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>. </li> </ul> <emu-note>Note<div class="note-contents"> An alternative <emu-xref href="#sec-static-semantic-rules" id="_ref_7202"><a href="notational-conventions.html#sec-static-semantic-rules">static semantics</a></emu-xref> for this production is given in <emu-xref href="#sec-variablestatements-in-catch-blocks" id="_ref_457"><a href="additional-ecmascript-features-for-web-browsers.html#sec-variablestatements-in-catch-blocks">B.3.4</a></emu-xref>. </div></emu-note> </emu-clause> <emu-clause id="sec-runtime-semantics-catchclauseevaluation" type="sdo" aoid="CatchClauseEvaluation"> <h1>14.15.2 Runtime Semantics: CatchClauseEvaluation</h1> The <emu-xref href="#sec-algorithm-conventions-syntax-directed-operations" id="_ref_7203"><a href="notational-conventions.html#sec-algorithm-conventions-syntax-directed-operations">syntax-directed operation</a></emu-xref> CatchClauseEvaluation takes argument <var>thrownValue</var> (an <emu-xref href="#sec-ecmascript-language-types" id="_ref_7204"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>) and returns either a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7205"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion containing</a></emu-xref> either an <emu-xref href="#sec-ecmascript-language-types" id="_ref_7206"><a href="ecmascript-data-types-and-values.html#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref> or <emu-const>empty</emu-const>, or an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7207"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>. It is defined piecewise over the following productions: <emu-grammar><emu-production name="Catch" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="3ce8nhiw" id="prod-tivA4mFO"> <emu-t>catch</emu-t> <emu-t>(</emu-t> <emu-nt id="_ref_20932"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> <emu-t>)</emu-t> <emu-nt id="_ref_20933"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>oldEnv</var> be the <emu-xref href="#running-execution-context" id="_ref_7208"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment.</li><li>Let <var>catchEnv</var> be <emu-xref aoid="NewDeclarativeEnvironment" id="_ref_7209"><a href="executable-code-and-execution-contexts.html#sec-newdeclarativeenvironment">NewDeclarativeEnvironment</a></emu-xref>(<var>oldEnv</var>).</li><li>For each element <var>argName</var> of the <emu-xref aoid="BoundNames" id="_ref_7210"><a href="syntax-directed-operations.html#sec-static-semantics-boundnames">BoundNames</a></emu-xref> of <emu-nt id="_ref_20934"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt>, do<ol><li>Perform ! <var>catchEnv</var>.CreateMutableBinding(<var>argName</var>, <emu-val>false</emu-val>).</li></ol></li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7211"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>catchEnv</var>.</li><li>Let <var>status</var> be <emu-xref aoid="Completion" id="_ref_7212"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="BindingInitialization" id="_ref_7213"><a href="syntax-directed-operations.html#sec-runtime-semantics-bindinginitialization" class="e-user-code">BindingInitialization</a></emu-xref> of <emu-nt id="_ref_20935"><a href="ecmascript-language-statements-and-declarations.html#prod-CatchParameter">CatchParameter</a></emu-nt> with arguments <var>thrownValue</var> and <var>catchEnv</var>).</li><li>If <var>status</var> is an <emu-xref href="#sec-completion-record-specification-type" id="_ref_7214"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">abrupt completion</a></emu-xref>, then<ol><li>Set the <emu-xref href="#running-execution-context" id="_ref_7215"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return ? <var>status</var>.</li></ol></li><li>Let <var>B</var> be <emu-xref aoid="Completion" id="_ref_7216"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7217"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20936"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>).</li><li>Set the <emu-xref href="#running-execution-context" id="_ref_7218"><a href="executable-code-and-execution-contexts.html#running-execution-context">running execution context</a></emu-xref>'s LexicalEnvironment to <var>oldEnv</var>.</li><li>Return ? <var>B</var>.</li></ol></emu-alg> <emu-grammar><emu-production name="Catch" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="oyp2rsut" id="prod-7Gz_IT_v"> <emu-t>catch</emu-t> <emu-nt id="_ref_20937"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Return ? <emu-xref aoid="Evaluation" id="_ref_7219"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20938"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>.</li></ol></emu-alg> <emu-note>Note<div class="note-contents"> No matter how control leaves the <emu-nt id="_ref_20939"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> the LexicalEnvironment is always restored to its former state. </div></emu-note> </emu-clause> <emu-clause id="sec-try-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.15.3 Runtime Semantics: Evaluation</h1> <emu-grammar><emu-production name="TryStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-TryStatement">TryStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="qhfov2lc" id="prod-TjGqXGk4"> <emu-t>try</emu-t> <emu-nt id="_ref_20940"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> <emu-nt id="_ref_20941"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>B</var> be <emu-xref aoid="Completion" id="_ref_7220"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7221"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20942"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>).</li><li>If <var>B</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7222"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">throw completion</a></emu-xref>, let <var>C</var> be <emu-xref aoid="Completion" id="_ref_7223"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="CatchClauseEvaluation" id="_ref_7224"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-catchclauseevaluation" class="e-user-code">CatchClauseEvaluation</a></emu-xref> of <emu-nt id="_ref_20943"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> with argument <var>B</var>.<var class="field">[[Value]]</var>).</li><li>Else, let <var>C</var> be <var>B</var>.</li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_7225"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>C</var>, <emu-val>undefined</emu-val>).</li></ol></emu-alg> <emu-grammar><emu-production name="TryStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-TryStatement">TryStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="xsakufa6" id="prod-BNnGZMkj"> <emu-t>try</emu-t> <emu-nt id="_ref_20944"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> <emu-nt id="_ref_20945"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>B</var> be <emu-xref aoid="Completion" id="_ref_7226"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7227"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20946"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>).</li><li>Let <var>F</var> be <emu-xref aoid="Completion" id="_ref_7228"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7229"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20947"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a></emu-nt>).</li><li>If <var>F</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7230"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion</a></emu-xref>, set <var>F</var> to <var>B</var>.</li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_7231"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>F</var>, <emu-val>undefined</emu-val>).</li></ol></emu-alg> <emu-grammar><emu-production name="TryStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-TryStatement">TryStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="gxlzfd5s" id="prod-fUrDxi55"> <emu-t>try</emu-t> <emu-nt id="_ref_20948"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt> <emu-nt id="_ref_20949"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> <emu-nt id="_ref_20950"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a></emu-nt> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>Let <var>B</var> be <emu-xref aoid="Completion" id="_ref_7232"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7233"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20951"><a href="ecmascript-language-statements-and-declarations.html#prod-Block">Block</a></emu-nt>).</li><li>If <var>B</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7234"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">throw completion</a></emu-xref>, let <var>C</var> be <emu-xref aoid="Completion" id="_ref_7235"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="CatchClauseEvaluation" id="_ref_7236"><a href="ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-catchclauseevaluation" class="e-user-code">CatchClauseEvaluation</a></emu-xref> of <emu-nt id="_ref_20952"><a href="ecmascript-language-statements-and-declarations.html#prod-Catch">Catch</a></emu-nt> with argument <var>B</var>.<var class="field">[[Value]]</var>).</li><li>Else, let <var>C</var> be <var>B</var>.</li><li>Let <var>F</var> be <emu-xref aoid="Completion" id="_ref_7237"><a href="notational-conventions.html#sec-completion-ao">Completion</a></emu-xref>(<emu-xref aoid="Evaluation" id="_ref_7238"><a href="syntax-directed-operations.html#sec-evaluation" class="e-user-code">Evaluation</a></emu-xref> of <emu-nt id="_ref_20953"><a href="ecmascript-language-statements-and-declarations.html#prod-Finally">Finally</a></emu-nt>).</li><li>If <var>F</var> is a <emu-xref href="#sec-completion-record-specification-type" id="_ref_7239"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">normal completion</a></emu-xref>, set <var>F</var> to <var>C</var>.</li><li>Return ? <emu-xref aoid="UpdateEmpty" id="_ref_7240"><a href="ecmascript-data-types-and-values.html#sec-updateempty">UpdateEmpty</a></emu-xref>(<var>F</var>, <emu-val>undefined</emu-val>).</li></ol></emu-alg> </emu-clause> </emu-clause> <emu-clause id="sec-debugger-statement"> <h1>14.16 The <code>debugger</code> Statement</h1> <h2>Syntax</h2> <emu-grammar type="definition"><emu-production name="DebuggerStatement" id="prod-DebuggerStatement"> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-DebuggerStatement">DebuggerStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ns5hclvt" id="prod-Kx8jxmHA"> <emu-t>debugger</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-clause id="sec-debugger-statement-runtime-semantics-evaluation" type="sdo"> <h1>14.16.1 Runtime Semantics: Evaluation</h1> <emu-note>Note<div class="note-contents"> Evaluating a <emu-nt id="_ref_20954"><a href="ecmascript-language-statements-and-declarations.html#prod-DebuggerStatement">DebuggerStatement</a></emu-nt> may allow an implementation to cause a breakpoint when run under a debugger. If a debugger is not present or active this statement has no observable effect. </div></emu-note> <emu-grammar><emu-production name="DebuggerStatement" collapsed=""> <emu-nt><a href="ecmascript-language-statements-and-declarations.html#prod-DebuggerStatement">DebuggerStatement</a></emu-nt> <emu-geq>:</emu-geq> <emu-rhs a="ns5hclvt" id="prod-eDCsgVlr"> <emu-t>debugger</emu-t> <emu-t>;</emu-t> </emu-rhs> </emu-production> </emu-grammar> <emu-alg><ol><li>If an <emu-xref href="#implementation-defined" id="_ref_7241"><a href="overview.html#implementation-defined">implementation-defined</a></emu-xref> debugging facility is available and enabled, then<ol><li>Perform an <emu-xref href="#implementation-defined" id="_ref_7242"><a href="overview.html#implementation-defined">implementation-defined</a></emu-xref> debugging action.</li><li>Return a new <emu-xref href="#implementation-defined" id="_ref_7243"><a href="overview.html#implementation-defined">implementation-defined</a></emu-xref> <emu-xref href="#sec-completion-record-specification-type" id="_ref_7244"><a href="ecmascript-data-types-and-values.html#sec-completion-record-specification-type">Completion Record</a></emu-xref>.</li></ol></li><li>Else,<ol><li>Return <emu-const>empty</emu-const>.</li></ol></li></ol></emu-alg> </emu-clause> </emu-clause> </emu-clause></div></body>