SWC vs Terser

SWC is a free, extensible Rust-based platform for tools that compile and bundle JavaScript and TypeScript. It transforms modern JavaScript and TypeScript into code intended for major browsers, and supports minification, WebAssembly transforms, and custom plugins. Its core API parses ECMAScript, TypeScript, and Flow syntax; the documentation describes that API as mainly useful to build-tool authors. Integrations include webpack, Rspack, and Jest, while Next.js, Parcel, and Deno are among the tools named as users. A WebAssembly module can transform code synchronously inside a browser. SWC can be installed as prebuilt binaries or built from source, with packages documented for npm, Yarn, pnpm, Bun, and Deno. The site states that it is 20x faster than Babel on one thread and 70x faster on four cores. The bundling documentation says that feature will be dropped in v2 and recommends SWC-based bundlers instead. It also warns that its polyfill usage mode is less efficient than Babel for certain dynamically computed property expressions.

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.