Important Changes

New Features

• Support for OutputOptions.file has been added.
• Treeshaking is now available for dynamic import(...).
• Legal comments can be preserved using OutputOptions#comments: 'preserve-legal'.
• A new build API has been introduced for more user-friendly programmatic usage.

// Instead of
(await (await rolldown(options)).write(options.output))

// Use `build`
await build(options)

UX Improvements

• The platform is automatically set to node when the output format is cjs, if not specified.
• Automatic polyfill for require is provided when bundling code that mixes ESM and CJS to format: 'esm' with platform: 'node'.
• Automatic polyfill for import.meta.url is provided when bundling ESM code to format: 'cjs' with platform: 'node'.

Correctness

• To improve interoperability between ESM and CJS, Rolldown passes all tests listed in bundler-esm-cjs-tests.

esbuild:  ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅
rolldown: ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅
node:     ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ 🚫🚫 ✅✅ 🚫🚫 🚫🚫 🚫🚫 🚫🚫 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅
webpack:  🚫🚫 🚫🚫 ✅🚫 🚫🚫 🚫🚫 ✅🚫 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ 🚫🚫 🚫🚫 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅
parcel:   ✅✅ ✅✅ 🚫🚫 🚫🚫 🚫🚫 🚫🚫 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ 🚫🚫 🚫🚫 🚫🚫 ✅✅ 🚫🚫 🚫🚫 🚫🚫 🚫🚫 ✅✅ 🚫🚫 🚫🚫 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅
rollup:   🚫🚫 🚫🚫 ✅✅ 🚫✅ ✅✅ ✅✅ 🚫🚫 🚫🚫 🚫🚫 🚫🚫 ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ ✅✅ 🚫🚫 ✅✅ ✅✅ 🚫🚫 ✅✅ ✅✅ ✅✅ 🚫🚫 🚫🚫 🚫🚫 🚫🚫 🚫🚫 🚫🚫 🚫🚫 🚫🚫 ✅✅

For more details, see ref.

• Rolldown promises to run successfully on all LTS Node.js versions. Our full test suites are enabled on Node.js versions 18, 20, and 22.
• Fresh self-bootstrapping for every commit: Rolldown now rebuilds itself with the code in each commit and runs all tests to ensure correctness.

More changes

Please refer to https://github.com/rolldown/rolldown/blob/main/CHANGELOG.md.

New Contributors

• @thesmartwon made their first contribution in #2636
• @eolme made their first contribution in #2732
• @gautemo made their first contribution in #2809

Full Changelog: v0.14.0...v0.15.0