feat(source-map): add extract option

[zalishchuk]

Summary

Adds a output.sourceMap.extract option, so Rspack's rules[].extractSourceMap can be enabled.

This implementation supports JS extraction only. I considered CSS extraction as well, but the current CSS pipeline does not preserve upstream CSS source maps end to end. Keeping sourceMap.extract as its own namespace still gives a clear place to support CSS in the future if that becomes possible.

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Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[Copilot]

Pull request overview

Adds an output.sourceMap.extract configuration namespace to enable Rspack’s rules[].extractSourceMap, allowing Rsbuild to preserve upstream JavaScript source maps (e.g. from packages shipping .js + .js.map).

Changes:

• Extend output.sourceMap config/types/defaults with a new extract option.
• Apply extractSourceMap: true via a dedicated Rspack rule when extraction is enabled (with optional include/exclude filtering).
• Add unit + e2e coverage and update docs/snapshots accordingly.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
website/docs/en/config/output/source-map.mdx	Documents the new sourceMap.extract option and examples.
packages/core/src/types/config.ts	Adds public types for SourceMapExtract / SourceMapExtractTarget and wires extract into SourceMap.
packages/core/src/defaultConfig.ts	Sets output.sourceMap.extract default to false.
packages/core/src/plugins/sourceMap.ts	Implements extraction rule injection (extractSourceMap: true) with include/exclude support.
packages/core/src/index.ts	Re-exports the new types from the public entrypoint.
packages/core/tests/sourceMap.test.ts	Adds unit tests verifying rule injection + include/exclude normalization behavior.
packages/core/tests/snapshots/environments.test.ts.snap	Updates snapshots for the normalized environment config (extract: false).
e2e/cases/source-map/extract/src/index.js	New e2e entry importing a package intended to have upstream maps.
e2e/cases/source-map/extract/index.test.ts	New e2e assertions that upstream maps are preserved when extraction is enabled.

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[chenjiahan]

Maybe we can add the extractSourceMap: true option to the built-in rule when extract is true, instead of creating a new rule.

[zalishchuk]

@chenjiahan Do you expect sourceMap.extract to follow the built-in SWC rule scope?

I kept it separate because the built-in JS rule handles transpilation and typically ignores node_modules, while extraction mainly targets upstream maps from dependencies

[chenjiahan]

That makes sense. A separate rule provides more flexibility when handling node_modules. 👍

[Copilot]

Pull request overview

Adds a new output.sourceMap.extract configuration namespace to enable extracting upstream JavaScript source maps (via Rspack rules[].extractSourceMap) so packages that ship .js + .js.map can preserve original mappings in the final output.

Changes:

• Extend output.sourceMap config/type definitions to include extract (boolean or { js?: ... }) with default false.
• Implement extraction rule injection in plugin-source-map by adding a dedicated Rspack rule with extractSourceMap: true plus optional include/exclude.
• Add unit + e2e coverage and update environment normalization snapshots; document the new option.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
website/docs/en/config/output/source-map.mdx	Documents sourceMap.extract, updates type/default snippets, adds usage examples.
packages/core/tests/sourceMap.test.ts	Unit tests to assert extract rules are added/normalized correctly.
packages/core/tests/snapshots/environments.test.ts.snap	Snapshot updates for normalized sourceMap.extract: false.
packages/core/src/types/config.ts	Introduces SourceMapExtract* types and wires extract into SourceMap / normalized output config.
packages/core/src/plugins/sourceMap.ts	Adds pre-chain handler to inject extractSourceMap rule for JS with include/exclude support.
packages/core/src/index.ts	Exports SourceMapExtract and SourceMapExtractTarget as public types.
packages/core/src/defaultConfig.ts	Adds sourceMap.extract: false to default normalized output config.
e2e/cases/source-map/extract/src/index.js	New e2e fixture consuming a package with an upstream sourcemap.
e2e/cases/source-map/extract/index.test.ts	E2E test validating upstream sourcemaps are preserved when extraction is enabled.

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[chenjiahan]

Thank you! ❤️

[zalishchuk]

@chenjiahan Hi! I didn't expect this to merge so quickly, as I'm unsure if this configuration scheme is the best we can get. Also, since we can't change the "test" property for the rule itself, do you have any ideas on how we can do this properly?

CRA (outdated, but whatever) uses source-map-loader for .css files too, I am not sure that this does something since the behavior of source map chain for CSS in both webpack/rspack/rsbuild...