Rocket Loader with offline PWA

I have a web page with a lot of JS and Rocket Loader enabled.

I need to make it work offline as a PWA.

To make it work offline, it needs a service worker that caches all the CSS, JS, images etc that the page uses. As the page uses the rocket-loader.js file, it needs to cache that file too.

Can I take a copy of the rocket-loader.js file, put it my server and tell the service worker to cache that?

As I understand it, service workers can’t cache external files for offline use. So either need to disable Rocket Loader, or serve my own version.