onBeforeUnload not being triggered from a headless browser

Question

I am using pupeteer to work with headless Chrome on nodeJS.

I am navigating through a local website and scraping the content, reading all the anchor <a> URLS and saving their content in files.

const puppeteer = require('puppeteer'); 
const { URL } = require('url');
const fse = require('fs-extra'); 
const path = require('path');


puppeteer.launch().then(async browser => {
  const page = await browser.newPage();
  //Navigate to local website
  await page.goto('http://localhost:5976/',{"waitUntil": "networkidle0"});  

  //Gather all anchors on my webpage and save their URLs in an array
  const hrefs = await page.evaluate(() => {
      const anchors = document.querySelectorAll('a');
      return [].map.call(anchors, a => a.href);
    });
  browser.close();

  //Loop through all the URLs and call them
  for (var i = 0; i < hrefs.length; i++) {
     start(hrefs[i]);
  }

})

//Function to browse URL
async function start(urlToFetch) {

  const browser = await puppeteer.launch();
  const page = await browser.newPage();

  page.on('response', async (response) => {

     //Treat content of page

  });

  await page.goto(urlToFetch, {
    waitUntil: 'networkidle2'
  });

  setTimeout(async () => {
    await browser.close();
  }, 60000 * 4);
}

On the other hand, in my local website, for every page I am performing an AJAX call on

$(window).on("beforeunload", function() {  
    //AJAX call
};

I discovered that if I go through my website from a browser, this AJAX call is performed when I leave each page. But when I browse my website from a headless browser through the NodeJS code above, the AJAX call doesn't get called

To verify, I put the AJAX call in DOMContentLoaded event and it was called from the headless browser. So the problem is with onBeforeUnload

It could be that in my nodeJS code I am not closing every page so the event is not being called.

I was wondering what can I changed the event to, to call AJAX last thing on a page both on headless browsers and normal browsers?

Answer 1

Since pptr v1.4.0, you can pass runBeforeUnload option to the page.close method:

await page.close({runBeforeUnload: true});