migrate-to-rslib

name	migrate-to-rslib
description	Migrate tsc or tsup library projects to Rslib. Use when users ask to replace tsc/tsup library build pipelines with Rslib while keeping package behavior stable.

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.