Javascript 记录已到达底部滚动条

const puppeteer = require('puppeteer');

let thumbArr = []
const scrapeInfiniteScrollItems = async(page) => {
  while (true) {
    const previousHeight = await page.evaluate(
      "document.querySelector('ytd-app').scrollHeight"
    );
    await page.evaluate(() => {
      const youtubeScrollHeight =
        document.querySelector("ytd-app").scrollHeight;
      window.scrollTo(0, youtubeScrollHeight);
    });
    await page.waitForFunction(
      `document.querySelector('ytd-app').scrollHeight > ${previousHeight}`, {
        timeout: 0
      }
    );

    const thumbnailLength = (await page.$$('ytd-grid-video-renderer')).length
    //this logs the amount of thumbnails every loop but once bottom scroll has        been reached it stops logging (obviously) but the question is how am I supposed to compare the last amount of thumbnail's found with total thumbnails once the loop has stopped running. Take a look below to better understand my question.
    thumbArr.push(thumbnailLength)

    if (thumbnailLength == thumbArr.at(-1)) {
      console.log('bottom has been reached')
    }

    await page.waitForTimeout(1000)
  }
};

(async() => {
  const browser = await puppeteer.launch({
    headless: false
  });
  const page = await browser.newPage();
  await page.goto('https://www.youtube.com', {
    waitUntil: 'networkidle2',
  });

  await scrapeInfiniteScrollItems(page)
})();

let clientHeightArr = []
let clientHeightArrTracker = []
const scrapeInfiniteScrollItems = async(browser, page) => {
  var infiniteScrollTrackerInterval = setInterval(async() => {
    clientHeightArrTracker.push(clientHeightArr.length)
    if (clientHeightArrTracker.some((e, i, arr) => arr.indexOf(e) !== i) == true) {
      clearInterval(infiniteScrollTrackerInterval)
      console.log('Bottom is reached')
      //causes error "ProtocolError: Protocol error (Runtime.callFunctionOn): Target closed."
      await browser.close()
    }
  }, 2000)
  while (true) {
    const previousHeight = await page.evaluate(
      "document.querySelector('ytd-app').scrollHeight"
    );

    await page.evaluate(() => {
      const youtubeScrollHeight =
        document.querySelector("ytd-app").scrollHeight;
      window.scrollTo(0, youtubeScrollHeight);
    });

    await page.waitForFunction(
      `document.querySelector('ytd-app').scrollHeight > ${previousHeight}`, {
        timeout: 0
      },
    );

    const clientHeight = await page.$$eval("ytd-app", el => el.map(x => x.clientHeight));
    clientHeightArr.push(clientHeight[0])
    await page.waitForTimeout(1000)
  }
};

(async() => {
  const browser = await puppeteer.launch({
    headless: false
  });
  const page = await browser.newPage();
  await page.goto('https://www.youtube.com/c/mkbhd/videos', {
    waitUntil: 'networkidle2',
  });

  await scrapeInfiniteScrollItems(browser, page)
})();