Capturing Custom JavaScript Event Listeners in Puppeteer

Other Questions Puppeteer
1

I’m working with Puppeteer and want to intercept custom events triggered within a web page. My specific scenario involves detecting custom event dispatches on the window object. Here’s an example of the current event setup:

var customAlert = new CustomEvent('notification', { detail: 'ready' });
window.addEventListener('notification', function(e) {
  console.log('Current status: ', e.detail);
});
setInterval(window.dispatchEvent, 1000, customAlert);

My goal is to find a reliable method to capture and respond to these dynamically dispatched events using Puppeteer’s API. How can I effectively listen and react to these custom JavaScript events during page automation?

2

For capturing custom events, I've found a neat approach using `page.evaluate()` combined with setting up a global event listener. Here's a practical technique I've used in my Puppeteer scripts:

You can create a global flag or buffer to capture event details dynamically. By modifying the page context with an event listener that logs to a global variable, you can then retrieve the captured information during your Puppeteer automation. The key is making sure the event data is accessible outside the browser's native event system.

For instance, instead of just logging, you could store event details in `window.eventBuffer` and then retrieve them later using `page.evaluate()`. This gives you more flexibility in tracking and responding to custom events without complex event interception methods.

3

yo, u can use page.on('console') or add global var in page context 2 track events. just expose a func w/ page.exposeFunction() & ur good 2 go! works like magic in my exp w puppeteer :+1:

4

In my Puppeteer projects, I've successfully captured custom events by using a combination of `page.evaluate()` and strategically placed event listeners. The trick is creating a bridge between the browser's event system and your Puppeteer script.

One reliable method I've found is to attach a global event listener that pushes event details into a predefined array. Inside your Puppeteer script, you can then retrieve and analyze this array. This approach provides a clean, non-intrusive way of tracking custom events without modifying the page's core event dispatching mechanism.

The key is maintaining a lightweight, unobtrusive mechanism that captures event data without introducing significant performance overhead or altering the page's original JavaScript execution flow.

5

hey! try using page.on('console') method + global var tracking. u can also expose function w/ page.exposeFunction() 2 capture events realtime. ez solution that works rly smooth! just make sure 2 handle async stuff carefully :rocket: