@wtubog , requestAnimationFrame is in the zone, https://stackblitz.com/edit/typescript-jxdndx?file=index.ts, I created a demo based on your stackblitz.

Hi @JiaLiPassion thanks for the quick reply.

Please try to zoom in and out on map and notice that requestAnimationFrame isn't being intercepted inside the forked Zone... I knew that Google Maps is triggering requestAnimationFrame because when you go to the Performance tab of chrome devtools, you'll see the call stack, and it triggers it when you zoom in, out and pan on the map...

@wtubog , the reason zoom not trigger reqeustAnimationFrame in mapZone, because it is in root zone, the wheel event listener was added to google map when loading https://maps.googleapis.com/maps/api/js, so it is not in mapZone.

If there are gmaps api that can add customized wheel event handler, you can add it into mapZone.

A map instance has a method addListener and then you specify the event name, in this case zoom_changed and then the callback function (https://stackblitz.com/edit/typescript-ugi7tp?file=index.ts).. I think that the underlying implementation of addListener uses that wheel event handler that has been registered to the root zone...

Is there a way to tap into the root zone?

@wtubog , there is no way to change root zone, there maybe some hack to intercept the requestAnimationFrame, but your first post said you want to improve performance, let zone to intercept requestAnimationFrame or wheel may slow down performance.

@wtubog , I created a sample to override root zone, you can try it for performance test.
https://github.com/JiaLiPassion/customize-root-zone
I just deleted the google map key, for test , you need to add your key in index.html

close for now.