@liutsing/microbundle

A small Rollup-powered library bundler inspired by microbundle.

It builds TypeScript or JavaScript library entry points to ESM, CommonJS, and UMD outputs. Each format is emitted as readable and minified files by default, with sourcemaps and TypeScript declarations.

microbundle src/index.ts --format es,cjs,umd --name MyLibrary

Default outputs:

• dist/index.mjs
• dist/index.min.mjs
• dist/index.js
• dist/index.min.js
• dist/index.umd.js
• dist/index.umd.min.js
• types/index.d.ts

The bundler uses the consuming project's local typescript package when available. Dependencies, peer dependencies, optional dependencies, Node built-ins, and values passed through --external are treated as Rollup externals.

Minification

Minified files are generated with @rollup/plugin-terser only for .min.* outputs. Readable outputs are written without terser.

Current terser call:

terser()

This means @liutsing/microbundle does not currently pass custom terser options such as drop_console, passes, ecma, keep_fnames, or property mangling.

The effective defaults are:

• @rollup/plugin-terser enables sourceMap when Rollup sourcemaps are enabled.
• @rollup/plugin-terser passes module: true for ES output.
• @rollup/plugin-terser passes toplevel: true for CJS output.
• UMD output uses Terser defaults plus sourcemap handling.
• Terser enables compression and identifier mangling by default.
• Terser does not mangle object property names by default.
• Terser does not drop console.* by default.
• Terser compress.passes defaults to 1.
• Terser compress.unsafe defaults to false.

Use --no-minify or --no-compress to skip .min.* outputs.