There are three common scenarios for controlling output chunks:

• Default behavior: Each entry point generates its own file. If there is shared code, it is extracted into a separate chunk.
• Unbundle mode (also known as preserveModules): The output structure mirrors the source directory. Ideally, there are no additional files except for those in virtualDirname.
  • Currently, even if all files are specified as input, this ideal cannot be fully achieved: shared code is still extracted into a chunk, resulting in an output structure that does not perfectly match the source directory.
  • Implemented now.
• Single file mode: Each entry produces exactly one file with no import statements, which is typically required for CDN consumption. While inlineDynamicImports partially achieves this, shared chunk behavior must also be disabled (to simulate esbuild’s splitting behavior).
  • Example: If two entries both depend on shared.js and the output format is iife, the contents of shared.js should be duplicated in both output files.
  • Reproduction: https://stackblitz.com/edit/github-ehiwc7lh?file=rolldown.config.mjs
  • Workaround: You can now work around this issue by assigning a separate build configuration to each input. Example: https://stackblitz.com/edit/github-ehiwc7lh-pk9i7zur?file=rolldown.config.mjs

The last two one scenario currently presents the biggest challenge for migration.

Related Issues

• [Feature Request]: add support for preserveModules output option #2622 (preserveModules)
• [Feature Request]: turn off code splitting by opt-in #3986 (inlineDynamicImports)
• Unbundle Mode tsdown#78 (splitting)