tsdown

Name: tsdown
Availability: InStock
Author: mymx2

Bundle TypeScript and JavaScript libraries into ESM, CJS, IIFE, and UMD formats.

4|Updated Jun 10, 2026

Search Tags:#typescript #javascript #library #build #bundler #rolldown

Ready to run

npx skills add https://github.com/mymx2/foreman --skill tsdown-mymx2

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: tsdown
Source: https://github.com/mymx2/foreman/tree/main/.qoder/skills.collected/skills/tsdown
Command: npx skills add https://github.com/mymx2/foreman --skill tsdown-mymx2

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill solves the complexity and performance bottlenecks associated with bundling TypeScript and JavaScript libraries, providing a unified, high-speed solution that replaces fragmented build toolchains.

Core Features & Use Cases

Multi-Format Bundling: Effortlessly generate ESM, CJS, IIFE, and UMD outputs from a single configuration.
Type Declaration Generation: Automatically create and bundle .d.ts files with high-performance Oxc-powered transformations.
Use Case: When migrating a legacy library from tsup or setting up a new monorepo, use this Skill to standardize build pipelines, ensure type safety, and optimize bundle sizes for production.

Quick Start

Use the tsdown skill to configure my project to build a TypeScript library with both ESM and CJS formats and generate type declarations.

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 into ESM and CJS formats?▼

You can bundle a TypeScript library into ESM and CJS formats by configuring this Skill to output multiple target formats from a single configuration. It uses the Rolldown engine to process the builds efficiently and generate the required output files.

What is the best way to generate type declarations for a JavaScript library?▼

The best way to generate type declarations is using this Skill to automatically create and bundle .d.ts files. It uses high-performance Oxc-powered transformations during the build process to ensure type safety for your JavaScript library.

Can I migrate a legacy library build from tsup to another bundler?▼

Yes, you can migrate a legacy library build from tsup to this Skill. It supports migration from legacy bundlers, allowing you to standardize your build pipeline while maintaining tree-shaking and high-performance production builds.

Does this bundler support monorepo workspace management for TypeScript?▼

Yes, this bundler supports monorepo workspace management for TypeScript. You can use this Skill to standardize build pipelines across workspace packages, ensuring type safety and optimizing bundle sizes for production outputs.

Why use Rolldown for library bundling instead of traditional JavaScript tools?▼

Rolldown is used for library bundling to solve performance bottlenecks associated with fragmented build toolchains. It provides blazing-fast build speeds for TypeScript and JavaScript libraries while supporting advanced tree-shaking for optimized bundle sizes.