[Bug]: new URL in a library gives file:/// address (Web Workers related)

[wfjsw]

Version

System:
    OS: Windows 11 10.0.26100
    CPU: (16) x64 AMD Ryzen 7 5800H with Radeon Graphics         
    Memory: 1.35 GB / 27.86 GB
  Browsers:
    Edge: Chromium (131.0.2903.99)
    Internet Explorer: 11.0.26100.1882
  npmPackages:
    @rsbuild/core: ^1.2.17 => 1.3.11 
    @rsbuild/plugin-babel: ^1.0.5 => 1.0.5 
    @rsbuild/plugin-react: ^1.1.1 => 1.3.0

Details

I have an Rslib powered library that can spawn a Web Worker: https://github.com/wudevstac/csv-js

The result bundle of that library seems to be pretty normal, where the worker file is separated and is referenced via import.meta.url:
https://github.com/wudevstac/csv-js/blob/91ca6586c0e4ea3cdf38ceeca098467d2f38db95/src/parserWorker.ts

However, once I try to call the function that spawns the worker in another Rsbuild powered React site, it turns out that the site is trying to load the worker via file:/// URL. Such URL does not exist in the original library artifact.

Reproduce link

https://codesandbox.io/p/github/rspack-contrib/rsbuild-codesandbox-example/csb-hphzc5/draft/zealous-bush

Reproduce Steps

1. Load the dev mode
2. Upload a random CSV
3. Check DevTools error log

[chenjiahan]

I cannot access the CodeSandbox link, can you provide a GitHub repo instead? Thanks

[wfjsw]

https://github.com/wfjsw/rsbuild-codesandbox-example/tree/issue-5093

[chenjiahan]

After a quick look, I guess this problem is related to Rslib. I will transfer this issue to the Rslib repository.

[chenjiahan]

Related: #929

[Timeless0911]

You can upgrade @rslib/core to 0.7.0, and now we preserve the worker syntax via #959. Now the output is like below:

const worker = new Worker(new URL('./parserWorker.worker.ts', import.meta.url), {
    type: 'module'
});

And you can add an entry for parserWorker.worker.ts to generate a parserWorker.worker.js and modify your source code.

source: {
  entry: {
    index: './src/index.ts',
    'parserWorker.worker': './src/parserWorker.worker.ts',
  },
},