feat: allow custom worker

[dejour]

This PR offers a solution to #2550.

[dejour]

done @Shinigami92

[ebeloded]

Hey @dejour! Thank you for working on this.

This PR misses TypeScript support. Currently client.d.ts defines the following for the workers:

// web worker
declare module '*?worker' {
  const workerConstructor: {
    new (): Worker
  }
  export default workerConstructor
}

declare module '*?worker&inline' {
  const workerConstructor: {
    new (): Worker
  }
  export default workerConstructor
}

It means that TSC won't recognize import with additional parameters.

Is it not possible to implement this functionality without augmenting the import statement?

Here is what I mean:

import MyWorker from './worker?worker'

const worker = new MyWorker() // classic worker
const worker = new MyWorker({type: 'classic'}) // classic worker
const worker = new MyWorker({type: 'module'}) // module worker

[ebeloded]

And I couldn't make it work with classic worker.

// main
import MyWorker from './worker?worker&type=classic';

const worker = new MyWorker();
console.log({ worker });

// worker.ts
importScripts('www.gstatic.com/firebasejs/8.0.0/firebase-app.js') // use importScripts to verify classic-ness 
console.log(`worker here`, { firebase: firebase })

The generated worker file looks like this:

import '/@fs/Users/evgenijbeloded/Code/vendors/vite-classic-workers/packages/vite/dist/client/env.js'
importScripts("www.gstatic.com/firebasejs/8.0.0/firebase-app.js");
console.log(`ts worker here`, {firebase});

Which rightfully stumbles on the first line with SyntaxError:

Uncaught SyntaxError: Cannot use import statement outside a module

[dejour]

Is it not possible to implement this functionality without augmenting the import statement?

it seems possible.

The generated worker file looks like this:

import '/@fs/Users/evgenijbeloded/Code/vendors/vite-classic-workers/packages/vite/dist/client/env.js'
importScripts("www.gstatic.com/firebasejs/8.0.0/firebase-app.js");
console.log(`ts worker here`, {firebase});

Which rightfully stumbles on the first line with SyntaxError:

Uncaught SyntaxError: Cannot use import statement outside a module

import statement can only be used in module worker, this indeed is a problem needed to be fixed. if not augmenting the import statement, we can not change the way env.js is imported.

[ebeloded]

Is this PR abandoned?