javascript - Puppeteer evaluate function

Question

I'm new to pupetteer and I'm trying to understand how it's actually working through some examples:

So basically what I'm trying to do in this example is to extract number of views of a Youtube video. I've written a js line on the Chrome console that let me extract this information:

document.querySelector('#count > yt-view-count-renderer > span.view-count.style-scope.yt-view-count-renderer').innerText

Answer 1

It seems that wait for 1000 is not enough.

Try your solution with https://try-puppeteer.appspot.com/ and you will see.

However if you try the following solution, you will get the correct result

const browser = await puppeteer.launch();

const page = await browser.newPage();
await page.goto('https://www.youtube.com/watch?v=T5GSLc-i5Xo');

await page.waitForSelector('span.view-count');
const views = await page.evaluate(() => document.querySelector('span.view-count').textContent);
console.log('Number of views: ' + views);

await browser.close();