---

name: migrate-to-rslib description: Migrate tsc or tsup library projects to Rslib.

Migrate to Rslib

Goal

Migrate tsc and tsup projects to Rslib with minimal behavior changes and clear verification.

Supported source frameworks

• tsc
• tsup

Migration principles (must follow)

1. Official guide first: treat Rslib migration docs as source of truth.
2. Smallest-change-first: complete baseline migration first, then migrate advanced or custom behavior.
3. Do not change business logic: avoid touching source or business logic unless user explicitly asks.
4. Validate before cleanup: keep old tool dependencies/config temporarily if needed; remove only after Rslib is green.

Workflow

1. Detect source tool

   • tsup
     • Config: tsup.config.*
     • Dependency: tsup
     • Build script: uses tsup to build projects
   • tsc
     • Config: tsconfig.json or tsconfig.*.json
     • Dependency: typescript
     • Build script: uses tsc to build projects. And it should be noted that tsc used only for type checking (e.g., tsc --noEmit) does not make it a tsc build project.

2. Apply tool-specific migration deltas

   • tsc: references/tsc.md
   • tsup: references/tsup.md

3. Validate behavior

   • Run build command to verify the project builds successfully.
   • If issues remain, compare the old project configuration with the migration guide and complete any missing mappings.

4. Cleanup and summarize

   • Remove obsolete dependencies/config only after validation passes.
   • Summarize changed files, mapped options, and any remaining manual follow-ups.