Crawler example on Vercel using Puppeteer and NextJS API routes

[slug].js

const puppeteer = require('puppeteer-core');
const cheerio = require('cheerio');
const chrome = require('chrome-aws-lambda');

export default async (req, res) => {
  const slug = req?.query?.slug;
  if (!slug) {
    res.statusCode = 200
    res.setHeader('Content-Type', 'application/json')
    res.end(JSON.stringify({ id: null }))
    return;
  }

  const browser = await puppeteer.launch(
    process.env.NODE_ENV === 'production'
      ? {
          args: chrome.args,
          executablePath: await chrome.executablePath,
          headless: chrome.headless,
        }
      : {}
  );
  
  const page = await browser.newPage();
  page.setUserAgent('Opera/9.80 (J2ME/MIDP; Opera Mini/5.1.21214/28.2725; U; ru) Presto/2.8.119 Version/11.10');
  await page.goto(`https://m.youtube.com/${slug}/videos`);

  let content = await page.content();
  var $ = cheerio.load(content);
  $.prototype.exists = function (selector) {
    return this.find(selector).length > 0;
  }

  let id = null;
  const isLive = $('body').exists('[data-style="LIVE"]');
  if (isLive) {
    const url = $('ytm-compact-video-renderer .compact-media-item-image').attr('href');
    const arr = url.split('?v=');
    id = arr[1];
  }

  await browser.close();

  res.statusCode = 200
  res.setHeader('Content-Type', 'application/json')
  res.end(JSON.stringify({ id }))
}