tsdown is a next-generation TypeScript library bundler built on Rolldown and Oxc. It provides blazing-fast builds, automatic .d.ts generation, and seamless migration from tsup. Supports Rolldown/Rollup/Unplugin plugins and features smart dependency handling.
The skill is based on tsdown v0.20.1, generated at 2026-01-28.
Anthony's Preferences:
- •Build pure-ESM packages, avoid CJS
- •Always enable
dtsoption for type declarations - •Enable
exportsoption for auto-generated package exports
Core
| Topic | Description | Reference |
|---|---|---|
| Configuration | Config file setup, defineConfig, multiple configs | core-config |
| CLI | Command-line interface and options | core-cli |
| Entry Points | Entry files, aliases, glob patterns | core-entry |
Build Options
| Topic | Description | Reference |
|---|---|---|
| Output | Format (ESM/CJS/IIFE/UMD), directory, target, platform | options-output |
| Declaration Files | .d.ts generation, isolatedDeclarations, sourcemaps | options-dts |
| Dependencies | External, noExternal, dependency bundling | options-dependencies |
| Package Exports | Auto-generating exports, main, module fields | options-package-exports |
Features
| Topic | Description | Reference |
|---|---|---|
| Optimization | Tree shaking, minification, sourcemaps | features-optimization |
| Shims | CJS/ESM compatibility shims | features-shims |
| Unbundle Mode | Bundleless transpile-only builds | features-unbundle |
| Watch Mode | Auto-rebuild on file changes | features-watch |
Advanced
| Topic | Description | Reference |
|---|---|---|
| Plugins | Rolldown, Unplugin, Rollup, Vite plugins | advanced-plugins |
| Hooks | Build lifecycle hooks | advanced-hooks |
| Programmatic API | Using tsdown from code | advanced-programmatic |
| Rolldown Options | Customizing inputOptions and outputOptions | advanced-rolldown-options |
Recipes
| Topic | Description | Reference |
|---|---|---|
| Framework Support | Vue and React library bundling | recipes-frameworks |
| Migration | Migrating from tsup | recipes-migration |