tsdown

Bundle TypeScript libraries into dual ESM/CJS output with .d.ts generation.

Updated Jan 2, 2026

Search Tags:#typescript #library #bundler #esm #cjs #dts

Ready to run

npx skills add https://github.com/onmax/claude-config --skill tsdown-onmax

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: tsdown
Source: https://github.com/onmax/claude-config/tree/main/skills/tsdown
Command: npx skills add https://github.com/onmax/claude-config --skill tsdown-onmax

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill streamlines the process of bundling TypeScript libraries, offering a powerful and efficient alternative to tsup.

Core Features & Use Cases

TypeScript Bundling: Compiles TypeScript into dual ESM/CJS output with type declarations.
Optimized Builds: Leverages Rolldown and Oxc for fast and efficient bundling.
Use Case: When developing a new npm package written in TypeScript, use this Skill to configure its build process for optimal distribution across different module systems.

Quick Start

Run the tsdown command to build your project using its default configuration.

Frequently Asked Questions about tsdown

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I bundle a TypeScript library for dual ESM and CJS output?▼

By using this Skill, you compile TypeScript into dual ESM and CJS output while generating .d.ts type declarations. It leverages Rolldown and Oxc for high-performance compilation during library development.

What is the best way to generate type declarations when bundling TypeScript?▼

Generating type declarations when bundling TypeScript is handled natively by this Skill, which produces .d.ts files alongside dual ESM and CJS output. It leverages Rolldown and Oxc for high-performance compilation.

Does this TypeScript bundler support advanced configurations and plugin authoring?▼

Yes, this TypeScript bundler supports advanced configurations and plugin authoring. It streamlines the process of bundling TypeScript libraries, utilizing Rolldown and Oxc for optimized compilation and high-performance builds.

tsdown vs tsup: which tool is faster for compiling TypeScript libraries?▼

When comparing tsdown to tsup for compiling TypeScript libraries, tsdown offers a faster alternative by utilizing Rolldown and Oxc for high-performance compilation. It generates dual ESM/CJS output and .d.ts files efficiently.

When do I need to generate dual ESM and CJS output for an npm package?▼

You need to generate dual ESM and CJS output for an npm package to ensure optimal distribution across different module systems. This Skill configures the build process to output both formats along with .d.ts generation.