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class="col col--8"><p><img src="https://res.cloudinary.com/dyaskan9k/image/fetch/f_auto,q_auto/https://scrapeops-assets-2.nyc3.cdn.digitaloceanspaces.com/Playbooks/NodeJs-Web-Scraping-Playbook/Thumbnails/node-fetch-concurrent-requests.png" alt="Node-Fetch: How to Use &amp; Rotate Proxies" fetchpriority="high" loading="eager" class="top-header-img img_CujE"></p> <h1>Node-Fetch: Make Concurrent Requests</h1> <p>In this guide for <a href="/nodejs-web-scraping-playbook/">The NodeJs Web Scraping Playbook</a>, we will look at how to configure <a href="https://www.npmjs.com/package/node-fetch" target="_blank" rel="noopener noreferrer">Node-Fetch</a> to make concurrent requests so that you can increase the speed of your scrapers.</p> <p>The more concurrent threads you have, the more requests you can have active in parallel, and the faster you can scrape.</p> <p>So in this guide we will walk you through the <strong>best way to send concurrent requests</strong> with Node-Fetch:</p> <ul> <li><a href="#make-concurrent-requests-using-promiseall--bottleneck">Make Concurrent Requests Using Promise.all() &amp; Bottleneck</a></li> <li><a href="#adding-concurrency-to-scrapeops-scrapers-adding-concurrency-to-scrapeops-scrapers">Adding Concurrency To ScrapeOps Scrapers</a></li> </ul> <p>Let&#x27;s begin...</p> <!-- --> <!-- --> <div style="background-color:#f6fafe;border-radius:2px;border:1px solid #f0f0f3;padding:1.5rem;padding-bottom:2.5rem;padding-top:2.5rem;text-align:center;margin-top:2rem"><h3>Need help scraping the web?</h3><p style="margin-bottom:2rem">Then check out <a href="https://scrapeops.io/?utm_campaign=nodejs-web-scraping-playbook&amp;utm_source=article&amp;utm_medium=organic&amp;utm_content=node-fetch-concurrent-threads" style="color:#000;text-decoration:none;border-bottom:2px dashed #0d53d7;font-weight:600">ScrapeOps</a>, the complete toolkit for web scraping.</p><div style="display:flex;flex-direction:row;flex-wrap:wrap;justify-content:center"><div><div><img 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src="https://assets-scrapeops.nyc3.digitaloceanspaces.com/Icons/scrapeops-scheduler-icon.svg" alt="ScrapeOps Job Scheduling"></div><div><a href="https://scrapeops.io/monitoring-scheduling?utm_campaign=nodejs-web-scraping-playbook&amp;utm_source=article&amp;utm_medium=organic&amp;utm_content=node-fetch-concurrent-threads" style="color:#000;text-decoration:none;font-weight:600">Job Scheduling</a></div></div></div></div> <hr> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="make-concurrent-requests-using-promiseall--bottleneck">Make Concurrent Requests Using Promise.all() &amp; Bottleneck<a href="#make-concurrent-requests-using-promiseall--bottleneck" class="hash-link" aria-label="Direct link to Make Concurrent Requests Using Promise.all() &amp; Bottleneck" title="Direct link to Make Concurrent Requests Using Promise.all() &amp; Bottleneck">​</a></h2> <p>The first approach to making concurrent requests with Node-Fetch is to use Javascript&#x27;s <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all" target="_blank" rel="noopener noreferrer">Promise.all() functionality</a> and the <a href="https://www.npmjs.com/package/bottleneck" target="_blank" rel="noopener noreferrer">bottleneck package</a> to control the concurrency.</p> <p>Here is an example:</p> <div class="language-javascript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#d6deeb;--prism-background-color:#011627"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-javascript codeBlock_bY9V thin-scrollbar" style="color:#d6deeb;background-color:#011627"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports">fetch</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;node-fetch&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports">cheerio</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;cheerio&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports maybe-class-name">Bottleneck</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;bottleneck&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> </span><span class="token constant" style="color:rgb(130, 170, 255)">NUM_THREADS</span><span class="token plain"> </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token number" style="color:rgb(247, 140, 108)">5</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token comment" style="color:rgb(99, 119, 119);font-style:italic">// Example list of URLs to scrape</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> list_of_urls </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">[</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/1/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/2/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/3/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/4/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/5/&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">]</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> output_data_list </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">[</span><span class="token punctuation" style="color:rgb(199, 146, 234)">]</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> limiter </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">new</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(255, 203, 139)">Bottleneck</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token literal-property property" style="color:rgb(128, 203, 196)">maxConcurrent</span><span class="token operator" style="color:rgb(127, 219, 202)">:</span><span class="token plain"> </span><span class="token constant" style="color:rgb(130, 170, 255)">NUM_THREADS</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">async</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">function</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">scrape_page</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token parameter">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">try</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> response </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">await</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">fetch</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> html </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">await</span><span class="token plain"> response</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">text</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">if</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">response</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token property-access">status</span><span class="token plain"> </span><span class="token operator" style="color:rgb(127, 219, 202)">===</span><span class="token plain"> </span><span class="token number" style="color:rgb(247, 140, 108)">200</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> $ </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> cheerio</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">load</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">html</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> title </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">$</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;h1&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">text</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token comment" style="color:rgb(99, 119, 119);font-style:italic">// Add scraped data to &quot;output_data_list&quot; array</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> output_data_list</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">push</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string-property property" style="color:rgb(128, 203, 196)">&#x27;title&#x27;</span><span class="token operator" style="color:rgb(127, 219, 202)">:</span><span class="token plain"> title</span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">catch</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">error</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token console class-name" style="color:rgb(255, 203, 139)">console</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">log</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;Error&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> error</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token keyword" style="color:rgb(127, 219, 202)">async</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token arrow operator" style="color:rgb(127, 219, 202)">=&gt;</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">await</span><span class="token plain"> </span><span class="token known-class-name class-name" style="color:rgb(255, 203, 139)">Promise</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">all</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> list_of_urls</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">map</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token parameter">url</span><span class="token plain"> </span><span class="token arrow operator" style="color:rgb(127, 219, 202)">=&gt;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> limiter</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">schedule</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token arrow operator" style="color:rgb(127, 219, 202)">=&gt;</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">scrape_page</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token console class-name" style="color:rgb(255, 203, 139)">console</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">log</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">output_data_list</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Here we:</p> <ol> <li> <p>We import the necessary libraries: <code>node-fetch</code>, <code>cheerio</code>, and <code>Bottleneck</code>. <code>fetch</code> method from <code>node-fetch</code> is used for making HTTP requests, <code>cheerio</code> is used for parsing the HTML response, and <code>Bottleneck</code> is used for limiting the number of concurrent threads.</p> </li> <li> <p>We define the <code>NUM_THREADS</code> constant, which represents the maximum number of concurrent threads we want to allow for scraping.</p> </li> <li> <p>We create an array <code>list_of_urls</code> containing the URLs we want to scrape.</p> </li> <li> <p>We define an empty array <code>output_data_list</code> to store the scraped data. In your code, you could have this data being saved to a queue.</p> </li> <li> <p>We create an instance of Bottleneck called limiter with maxConcurrent option set to <code>NUM_THREADS</code>. This ensures that at most <code>NUM_THREADS</code> requests are executed concurrently.</p> </li> <li> <p>We define the <code>scrape_page</code> function, which takes a <code>url</code> as an argument and performs the scraping for that url. Inside the function:</p> </li> </ol> <ul> <li>We call <code>fetch</code> method from <code>node-fetch</code> to send an HTTP <code>GET</code> request to the URL and obtain the response. Then we load <code>html</code> response text using <code>response.text</code> method.</li> <li>If the response&#x27;s status code is <code>200</code> (indicating a successful response), we load the response into cheerio using <code>cheerio.load(html)</code>.</li> <li>We extract the <code>title</code> from the HTML using <code>$(&#x27;h1&#x27;).text()</code> and add it to the <code>output_data_list</code> array as an object with a &#x27;title&#x27; property.</li> </ul> <ol start="6"> <li>We use <code>Promise.all()</code> to map each URL in <code>list_of_urls</code> to a call to <code>limiter.schedule()</code>. This schedules the <code>scrape_page</code> function for each URL, enforcing the concurrency limit set by limiter.</li> <li><code>limiter.schedule()</code> returns a promise for each URL, and <code>Promise.all()</code> waits for all the promises to resolve. Once all the promises are resolved, we reach the await line, and execution continues to the next line.</li> <li>We log the <code>output_data_list</code> to the console, which contains the scraped data from all the URLs.</li> </ol> <p>Overall, the code sets a concurrency limit using <code>Bottleneck</code> and utilizes <code>node-fetch</code> and <code>cheerio</code> for making HTTP requests and parsing the HTML response, respectively. The scraping is done concurrently for multiple URLs, and the scraped data is collected in an array.</p> <p>Using this approach we can significantly increase the speed at which we can make requests with Node-Fetch library.</p> <hr> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="adding-concurrency-to-scrapeops-scrapers">Adding Concurrency To ScrapeOps Scrapers<a href="#adding-concurrency-to-scrapeops-scrapers" class="hash-link" aria-label="Direct link to Adding Concurrency To ScrapeOps Scrapers" title="Direct link to Adding Concurrency To ScrapeOps Scrapers">​</a></h2> <p>The following is an example sending requests to the <a href="/proxy-aggregator/">ScrapeOps Proxy API Aggregator</a>, which enables you to use all the available threads your proxy plan allows you to make.</p> <p>Just change the <code>NUM_THREADS</code> value to the number of concurrent threads your proxy plan allows.</p> <div class="language-javascript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#d6deeb;--prism-background-color:#011627"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-javascript codeBlock_bY9V thin-scrollbar" style="color:#d6deeb;background-color:#011627"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports">fetch</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;node-fetch&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports">cheerio</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;cheerio&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports maybe-class-name">Bottleneck</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;bottleneck&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword module" style="color:rgb(127, 219, 202)">import</span><span class="token plain"> </span><span class="token imports">querystring</span><span class="token plain"> </span><span class="token keyword module" style="color:rgb(127, 219, 202)">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;querystring&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> </span><span class="token constant" style="color:rgb(130, 170, 255)">NUM_THREADS</span><span class="token plain"> </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token number" style="color:rgb(247, 140, 108)">5</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> </span><span class="token constant" style="color:rgb(130, 170, 255)">SCRAPEOPS_API_KEY</span><span class="token plain"> </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;YOUR_API_KEY&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"> </span><span class="token comment" style="color:rgb(99, 119, 119);font-style:italic">// Replace with your actual API key</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">function</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">get_scrapeops_url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token parameter">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> payload </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token literal-property property" style="color:rgb(128, 203, 196)">api_key</span><span class="token operator" style="color:rgb(127, 219, 202)">:</span><span class="token plain"> </span><span class="token constant" style="color:rgb(130, 170, 255)">SCRAPEOPS_API_KEY</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token literal-property property" style="color:rgb(128, 203, 196)">url</span><span class="token operator" style="color:rgb(127, 219, 202)">:</span><span class="token plain"> url</span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> proxy_url </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token template-string template-punctuation string" style="color:rgb(173, 219, 103)">`</span><span class="token template-string string" style="color:rgb(173, 219, 103)">https://proxy.scrapeops.io/v1/?</span><span class="token template-string interpolation interpolation-punctuation punctuation" style="color:rgb(199, 146, 234)">${</span><span class="token template-string interpolation">querystring</span><span class="token template-string interpolation punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token template-string interpolation method function property-access" style="color:rgb(130, 170, 255)">stringify</span><span class="token template-string interpolation punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token template-string interpolation">payload</span><span class="token template-string interpolation punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token template-string interpolation interpolation-punctuation punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token template-string template-punctuation string" style="color:rgb(173, 219, 103)">`</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">return</span><span class="token plain"> proxy_url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token comment" style="color:rgb(99, 119, 119);font-style:italic">// Example list of URLs to scrape</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> list_of_urls </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">[</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/1/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/2/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/3/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/4/&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;http://quotes.toscrape.com/page/5/&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">]</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> output_data_list </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">[</span><span class="token punctuation" style="color:rgb(199, 146, 234)">]</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> limiter </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">new</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(255, 203, 139)">Bottleneck</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token literal-property property" style="color:rgb(128, 203, 196)">maxConcurrent</span><span class="token operator" style="color:rgb(127, 219, 202)">:</span><span class="token plain"> </span><span class="token constant" style="color:rgb(130, 170, 255)">NUM_THREADS</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token keyword" style="color:rgb(127, 219, 202)">async</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">function</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">scrape_page</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token parameter">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">try</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> response </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">await</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">fetch</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token function" style="color:rgb(130, 170, 255)">get_scrapeops_url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> html </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">await</span><span class="token plain"> response</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">text</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">if</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">response</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token property-access">status</span><span class="token plain"> </span><span class="token operator" style="color:rgb(127, 219, 202)">===</span><span class="token plain"> </span><span class="token number" style="color:rgb(247, 140, 108)">200</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> $ </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> cheerio</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">load</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">html</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword" style="color:rgb(127, 219, 202)">const</span><span class="token plain"> title </span><span class="token operator" style="color:rgb(127, 219, 202)">=</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">$</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;h1&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">text</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token comment" style="color:rgb(99, 119, 119);font-style:italic">// Add scraped data to &quot;output_data_list&quot; array</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> output_data_list</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">push</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token string-property property" style="color:rgb(128, 203, 196)">&#x27;title&#x27;</span><span class="token operator" style="color:rgb(127, 219, 202)">:</span><span class="token plain"> title</span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">catch</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">error</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token console class-name" style="color:rgb(255, 203, 139)">console</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">log</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token string" style="color:rgb(173, 219, 103)">&#x27;Error&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> error</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token keyword" style="color:rgb(127, 219, 202)">async</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token arrow operator" style="color:rgb(127, 219, 202)">=&gt;</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token keyword control-flow" style="color:rgb(127, 219, 202)">await</span><span class="token plain"> </span><span class="token known-class-name class-name" style="color:rgb(255, 203, 139)">Promise</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">all</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> list_of_urls</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">map</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token parameter">url</span><span class="token plain"> </span><span class="token arrow operator" style="color:rgb(127, 219, 202)">=&gt;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> limiter</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">schedule</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token arrow operator" style="color:rgb(127, 219, 202)">=&gt;</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">scrape_page</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">url</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"> </span><span class="token console class-name" style="color:rgb(255, 203, 139)">console</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">log</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">output_data_list</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#d6deeb"><span class="token plain" style="display:inline-block"></span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>You can get your own <a href="https://scrapeops.io/app/register/proxy/" target="_blank" rel="noopener noreferrer">free API key with 1,000 free requests by signing up here</a>.</p> <hr> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="more-web-scraping-tutorials">More Web Scraping Tutorials<a href="#more-web-scraping-tutorials" class="hash-link" aria-label="Direct link to More Web Scraping Tutorials" title="Direct link to More Web Scraping Tutorials">​</a></h2> <p>So that&#x27;s how you can configure <a href="https://github.com/node-fetch/node-fetch" target="_blank" rel="noopener noreferrer">Node-Fetch</a> to send requests concurrently.</p> <p>If you would like to learn more about Web Scraping, then be sure to check out <a href="/web-scraping-playbook/">The Web Scraping Playbook</a>.</p> <p>Or check out one of our more in-depth guides:</p> <ul> <li><a href="/web-scraping-playbook/web-scraping-without-getting-blocked/">How to Scrape The Web Without Getting Blocked Guide</a></li> <li><a href="https://scrapeops.io/blog/the-state-of-web-scraping-2022/" target="_blank" rel="noopener noreferrer">The State of Web Scraping 2020</a></li> <li><a href="/web-scraping-playbook/ethics-of-web-scraping/">The Ethics of Web Scraping</a></li> </ul></div><div class="col col--2"><div class="tableOfContents_bqdL thin-scrollbar"><ul class="table-of-contents table-of-contents__left-border"><li><a href="#make-concurrent-requests-using-promiseall--bottleneck" class="table-of-contents__link toc-highlight">Make Concurrent Requests Using Promise.all() &amp; Bottleneck</a></li><li><a href="#adding-concurrency-to-scrapeops-scrapers" class="table-of-contents__link toc-highlight">Adding Concurrency To ScrapeOps Scrapers</a></li><li><a href="#more-web-scraping-tutorials" class="table-of-contents__link toc-highlight">More Web Scraping Tutorials</a></li></ul></div></div></div></main></div><footer class="footer footer--dark"><div class="container container-fluid"><div class="row footer__links"><div class="col footer__col"><div class="footer__title">Resources</div><ul class="footer__items clean-list"><li class="footer__item"><a class="footer__link-item" href="/docs/intro/">Documentation</a></li><li class="footer__item"><a href="https://scrapeops.io/proxy-providers/comparison/" target="_blank" rel="noopener noreferrer" class="footer__link-item">Proxy Comparison Tool</a></li><li class="footer__item"><a class="footer__link-item" href="/blog/">Blog</a></li><li class="footer__item"><a href="https://github.com/ScrapeOps" target="_blank" rel="noopener noreferrer" class="footer__link-item">GitHub</a></li></ul></div><div class="col footer__col"><div class="footer__title">Web Scraping Guides</div><ul class="footer__items clean-list"><li class="footer__item"><a class="footer__link-item" 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