feat: support worker script

[JE-lee]

I want to usenode:worker_threads.Worker for the heavy compute cost in the main process and something like hmr of the worker script files.
similar to the main script, it will restart the electron app when developing the worker script files.

changes:

1. add additional option of worker, similar to the preload option.

export interface Configuration {
  main: CommonConfiguration & {
    /**
     * Shortcut of `build.lib.entry`
     */
    entry: LibraryOptions['entry']
  }
  preload?: CommonConfiguration & {
    /**
     * Shortcut of `build.rollupOptions.input`
     */
    input: InputOption
  }
  worker?: CommonConfiguration & {
    input: InputOption
  }
  /**
   * Support use Node.js API in Electron-Renderer
   * @see https://github.com/electron-vite/vite-plugin-electron/tree/main/packages/electron-renderer
   */
  renderer?: Options
}

2. add example of how to use this.(playground/usecase-in-main)

[caoxiemeihao]

@JE-lee 👋
Thanks this great PR!
To support node:worker_threads we might have a better way to implementation it.

e.g.

// vite.config.ts
import electron from 'vite-plugin-elecctron'

export default {
  plugins: [electron({
    main: {
      input: {
        main: 'electron/main/index.ts',
        worker: 'electron/main/worker.ts',
      },
    },
  })],
}

usage

// electron/main/index.ts
import { Worker } from 'node:worker_threads'

const worker = new Worker(path.join(__dirname, './worker.js'))

---

So, we just need to add the Configuration['main']['input'] option and implement it. Do you think this is good? 😄

[JE-lee]

yes, Configuration['main']['input'] also achieves what i want.
But it will be a little confuse when putting the worker script and main script together.
It soulds like there is more than on entry of electron. 😂Maybe it doesn't matter.

[JE-lee]

Or maybe we need a new more configurable api.
something like that

export interface Configuration {
  build: Array<{
    input: string,
    output: string,
    restartWhenUpdate: boolean, // restart the electron app when saving change, like `main script` or `worker script`
    reloadWhenUpdate: boolean, // full reload the browser window, like `proload script`
  }>,
 /**
   * Support use Node.js API in Electron-Renderer
   * @see https://github.com/electron-vite/vite-plugin-electron/tree/main/packages/electron-renderer
   */
  renderer?: Options
}

[caoxiemeihao]

To support node:worker_threads we might have a better way to implementation it.

In this case. Electron-Main, Preload-script and Elecctron-Renderer will use the corresponding Vite configuration to build the corresponding environment-compatible code.

How, are you interested in implementing it? :)

[caoxiemeihao]

Or maybe we need a new more configurable api.

Adding additional APIs is not recommended unless Vite's configuration cannot implement it. We want to leave enought choices for users.

[caoxiemeihao]

Hi here! 👋
Thanks for you PR.
The feature implemented in v0.10.0 #89