Migrate 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.

tsc -> Rslib Migration Checklist

Use this reference when the source project builds libraries with tsc.

Checklist

Copy this checklist and check off items as you complete them:

• [ ] Step 0: Read official guide (https://rslib.rs/guide/migration/tsc) ⛔ BLOCKING
• [ ] Step 1: Inventory current tsc behavior and customizations
• [ ] Record key build scripts, tsc CLI options, and tsconfig.json usage
• [ ] Record key compile behavior and output behavior (JavaScript files format, declaration files output, output structure, JSX handling, etc.)
• [ ] Record output usage expectations (how outputs are consumed)
• [ ] Step 2: Execute migration following the official guide
• [ ] Apply guide steps with minimal scope
• [ ] Map customizations before and after tsc scripts
• [ ] Step 3: Verify behavior and output compatibility
• [ ] Build passes without errors
• [ ] Build with watch mode runs without errors and incremental rebuild works as expected
• [ ] Output structure, formats, file extensions, and declaration files match expectations
• [ ] Output can be consumed and run as expected
• [ ] Check whether package.json fields need updates (main, module, types, exports, files, bin, etc.)
• [ ] Step 4: Cleanup and summarize
• [ ] Remove obsolete tsc-only scripts after verification
• [ ] Summarize config mapping and remaining manual follow-ups

tsup -> Rslib Migration Checklist

Use this reference when the source project builds libraries with tsup.

Checklist

Copy this checklist and check off items as you complete them:

• [ ] Step 0: Read official guide (https://rslib.rs/guide/migration/tsup) ⛔ BLOCKING
• [ ] Step 1: Inventory current tsup behavior and customizations
• [ ] Record key build scripts, tsup CLI options, and configuration files
• [ ] Record key config/plugins and output behavior (format, d.ts, externals, output structure, etc.)
• [ ] Record output usage expectations (how outputs are consumed)
• [ ] Step 2: Execute migration following the official guide
• [ ] Apply guide steps with minimal scope
• [ ] Map plugins and other advanced customizations
• [ ] Step 3: Verify behavior and output compatibility
• [ ] Build passes without errors
• [ ] Build with watch mode runs without errors and incremental rebuild works as expected
• [ ] Output structure, formats, file extensions, and declaration files match expectations
• [ ] Output can be consumed and run as expected
• [ ] Check whether package.json fields need updates (main, module, types, exports, files, bin, etc.)
• [ ] Step 4: Cleanup and summarize
• [ ] Remove obsolete tsup-only deps/config/scripts after verification
• [ ] Summarize config mapping and remaining manual follow-ups