rolldown/tsdown
Tsdown
tsdown is a library bundler that uses a Rust-native core, built on Rolldown and the Oxc parser, to compile TypeScript and JavaScript source code into optimized output files. It is designed to produce bundles in multiple formats—ESM, CJS, IIFE, and UMD—from a single source, and automatically generates TypeScript declaration files during the build process for type-safe distribution.
The project distinguishes itself by offering a plugin system compatible with Rollup, Rolldown, unplugin, and some Vite plugins, allowing the build pipeline to be extended with custom transformations. It also accepts tsup's main options and features, enabling existing projects to migrate without rewriting their configuration. The bundler provides a zero-config setup that bundles source code and generates declarations without manual configuration.
The tool handles non-code assets like JSON and WebAssembly files, and its output pipeline is configurable for different module system targets. Documentation and installation details are available through the project's repository.
Features
- Rust-Based Library Bundle Builds - Building TypeScript and JavaScript libraries into optimized bundles using a Rust-based toolchain for fast, zero-config output.
- Rolldown-Based - Bundles libraries with Rolldown and Oxc for high-performance builds and automatic declaration file generation.
- JavaScript Module Format Converters - Produces bundles in ESM, CJS, IIFE, and UMD formats from a single source through a configurable output stage.
- JavaScript Module Format Outputs - Generate bundles in ESM, CJS, IIFE, and UMD formats for compatibility across different environments.
- Rollup-Compatible Plugin Integrations - Extending the build pipeline by supporting Rollup, Rolldown, unplugin, and some Vite plugins for custom transformations.
- Rust-Based Library Bundling - Bundle library source code into optimized output files using a high-performance Rust-based toolchain.
- TypeScript Declaration Emitters - Generates TypeScript declaration files (.d.ts) during the build process using a built-in declaration emitter.
- TypeScript Bundling - Bundle TypeScript and JavaScript files while supporting modern syntax and features.
- TypeScript Declaration Tooling - Generate declaration files automatically during the build process for the library.
- Declaration Files - Produce TypeScript declaration files alongside the bundle so consumers get full type information.
- Bundlers - Uses a Rust-based bundler (Rolldown) to perform parsing, linking, and code generation at high speed.
- Non-Code Asset Bundlers - Includes non-code assets like JSON and WebAssembly files in the bundle during processing.
- Build Plugin Integrations - Integrate with Rollup, Rolldown, unplugin, and some Vite plugins to extend the build pipeline.
- Distribution Build Configurations - Configure a library build with pre-set options for output files and declaration generation.
- Zero-Config Library Packaging - Provides a preconfigured build pipeline that bundles source code and generates TypeScript declarations without manual setup.
- tsup-Compatible Configurations - Accepts tsup’s main options and features to allow seamless migration without rewriting configuration files.
- tsup-Compatible Configurations - Accept tsup's main options and features so existing projects can switch without rewriting configuration.
- Plugin Ecosystem Adapters - Implements a plugin interface that accepts Rollup, Rolldown, unplugin, and some Vite plugins for extensibility.
- Rust-Based Parsers - Leverages the Oxc parser written in Rust to parse TypeScript and JavaScript with minimal overhead.
