fix: preserve filename and dirname for ESM bundles#6811
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chenjiahan merged 1 commit intomainfrom Dec 20, 2025
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Pull request overview
This PR disables automatic polyfills for __dirname, __filename, import.meta.dirname, and import.meta.filename in ESM bundles (when output.module is enabled) to preserve native Node.js and browser behavior.
Key Changes:
- Added configuration to disable
__dirnameand__filenamepolyfills in the ESM plugin - Added comprehensive test coverage for both web and node targets to verify the behavior
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| packages/core/src/plugins/esm.ts | Sets chain.node configuration to disable __dirname and __filename polyfills when ESM output is enabled |
| e2e/cases/polyfill/dirname-filename-web/src/index.js | Test source file that checks the types of dirname/filename variables in browser context |
| e2e/cases/polyfill/dirname-filename-web/rsbuild.config.ts | Configuration enabling ESM output for web target test |
| e2e/cases/polyfill/dirname-filename-web/index.test.ts | Test verifying that dirname/filename are not polyfilled (remain undefined) in web target |
| e2e/cases/polyfill/dirname-filename-node/src/index.js | Test source file that outputs dirname/filename values in Node.js context |
| e2e/cases/polyfill/dirname-filename-node/rsbuild.config.ts | Configuration enabling ESM output for node target test |
| e2e/cases/polyfill/dirname-filename-node/index.test.ts | Test verifying that dirname/filename are preserved as-is in the bundled output for node target |
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Summary
Disable automatic
__dirname/__filename/import.meta.dirname/import.meta.filenamepolyfills when output.module is enabled so ESM bundles preserve native Node.js / browser behavior.Related link
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