Use non-inline workers in browsers without module worker support

[NotWoods]

Is your feature request related to a problem? Please describe.
I'd like to build an app using large Web Worker scripts that runs in the latest version of Firefix & Safari.

Describe the solution you'd like
I want to have an alternate worker bundle output that can be used as a fallback if {type:'module'} workers aren't available. The scripts are large enough that I don't want to inline them, but instead use separate chunks. Duplication in each chunk is OK (although preferably not).

The bundled version wouldn't have any import statements, nor import() functions as dynamic import isn't supported in worker threads in Firefox.

try {
  new Worker('./moduule.js', { type: 'module' })
} catch (err) {
  new Worker('./bundle.js')
}

Describe alternatives you've considered
I think inline workers already remove import statements.

[yyx990803]

The built workers (even not inlined) are pre-bundled so for production it should work even if the browser doesn't support module workers. If it doesn't, please open a bug report.