I took great pains to support Firefox, mostly in my service worker.

Unfortunately when it comes to mounting drives for faster local development, there's nothing I can do until FF supports `showDirectoryPicker`

However, you could just load up a local file server in your local directory (python -m http.server 8080) and import your file directly:

  import 'http://localhost:8080/index.js'

Then put that one line of code inside usr/myapp.app.js and click it in filer[1]

You'll have to use filer to create the file and edit it by right-clicking, then type it in and ctrl-s to save or use the top-left menu button.

I'll add all of this to the website under some "Using Firefox" page or something, for people who can't stand Chrome.

[1] https://90s.dev/os/#sys/apps/filer.app.js@usr/