esbuild vs Terser

esbuild is a free bundler for web projects, designed to improve build-tool performance while remaining easy to use. It bundles ESM and CommonJS modules, including CSS modules, with built-in support for JavaScript, CSS, TypeScript and JSX. Optimization features include tree shaking, minification and source maps; development tools include a local server, watch mode and plugins. Developers can use the command-line, JavaScript or Go interface. The recommended installation is the native executable installed with npm. An alternative WebAssembly package works across platforms, though it can be substantially slower than the native package. esbuild is MIT-licensed. It does not type-check TypeScript, and its FAQ recommends running tsc separately. The FAQ describes code-splitting support as primitive. The maintainer says the project receives periodic releases and is maintained, but active feature development is not underway. The FAQ also notes that a project primarily built by one developer may not fit organizations seeking a larger or more active community.

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.