How to use rsbuild with outputFileSystem?

[dartess]

What I have: RsbuildConfig and the desire to get the build result in a variable, without writing files to disk.

rspack has the ability to specify a custom file system for the output with outputFileSystem option: https://www.rspack.dev/api/javascript-api#custom-file-systems.

I tried something like this, but when I add the compiler arg I get a build error Rspack build failed! (Resolve error: Can't resolve './src' in ...).

  const rsbuildInstance = await createRsbuild({ rsbuildConfig });
  const fs = createFsFromVolume(new Volume());
  const compiler = rspack({});
  compiler.outputFileSystem = fs;
  await rsbuildInstance.build({ compiler });

[chenjiahan]

Rsbuild provide a onAfterCreateCompiler API to access the compiler object, see: https://rsbuild.dev/api/javascript-api/instance#rsbuildonaftercreatecompiler

import { createRsbuild } from '@rsbuild/core';

const rsbuild = await createRsbuild({ rsbuildConfig });
const fs = createFsFromVolume(new Volume());

rsbuild.onAfterCreateCompiler(({ compiler }) => {
  compiler.outputFileSystem = fs;
});