Rolldown vs Terser

Rolldown is a free, open-source JavaScript bundler written in Rust and designed as the unified bundler powering Vite 8+. Its Rollup-compatible plugin API can reuse most existing Rollup plugins. Built-in capabilities include TypeScript and JSX transforms, syntax lowering, module resolution, ESM and CommonJS interoperability, define, inject, and minification. It can handle mixed ESM and CommonJS module graphs and supports configurable manual code splitting. Install commands are provided for npm, pnpm, yarn, bun, and vp. Prebuilt binaries are listed for Linux, Windows, Apple platforms, Android, and other targets; where none is distributed, a Wasm build or building from source are options. The guide recommends using Rolldown through Vite for most applications and points library authors to tsdown. Module types are experimental, and the JavaScript build() API may change in patch releases. The troubleshooting guide says Windows file-system access can slow builds, particularly when transforms run without plugins. An online REPL is linked, along with GitHub, Discord, and contribution resources. VoidZero Inc. holds the copyrights, funds development, and directs the project; it states Rolldown remains open source and MIT-licensed.

Terser is a free, open-source JavaScript minifier that reduces code by shortening variable names, removing whitespace and comments, and dropping unused code. It can be used through a command-line interface or Node.js API; browser loading is supported and exposes a global `Terser` variable with a `.minify` property. The API’s `minify()` enables compression and mangling by default, and both settings can be changed or turned off. The API can return a source map, while the CLI can generate source maps for compressed JavaScript. The CLI accepts multiple input files and parses them in sequence in one global scope, or reads from standard input when no input file is specified. Compatibility options include an ECMAScript target; `ecma` defaults to 5 for compression and output formatting. Property-name mangling can break code, so the documentation says to use it only when its behavior is understood. Built-in DOM property mangling is disabled by default and is not recommended for enabling. Terser also supports Acorn-produced SpiderMonkey AST input and a Yarn resolution alias for nested `uglify-es` dependencies.