Puppeteer Evaluate Function

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

Solution 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();

Solution 2:

Do not use hand made timeout to wait a page to load, unless you are testing whether the page can only in that amount of time. Differently from selenium where sometimes you do not have a choice other than using a timeout, with puppeteer you should always find some await function you can use instead of guessing a "good" timeout. As answered by Milan Hlinák, look into the page HTML code and figure out some HTML tag you can wait on, instead of using a timeout. Usually, wait for the HTML element(s) you test require in order to work properly. On you case, the span.view-count, as already answered by Milan Hlinák:

await page.waitForSelector('span.view-count');