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Minimize your JS files post-build — without creating a bundle.

Overview

minimize-js strips whitespace, rewrites identifiers, and collapses syntax across every file in a directory — powered by esbuild. No bundling, no module graph, no entry points. Just smaller files.

Perfect as a post-build step for libraries that compile TypeScript to CommonJS before publishing.

# Before
dist/index.js   →   42 kB
# After
dist/index.js   →   18 kB

Packages

This project is a monorepo. Two packages, one purpose.

| Package | Description | Install | |---------|-------------|---------| | minimize-js | CLI tool | npm i -D minimize-js | | @minimize-js/core | Programmatic API | npm i @minimize-js/core |

Installation

# npm
npm install minimize-js --save-dev

# pnpm
pnpm add minimize-js -D

# yarn
yarn add minimize-js --dev

Usage

CLI

minimize-js <directory> [options]

Run it on your compiled output directory:

minimize-js lib
minimize-js dist --minifyDeclaration
minimize-js lib --banner "/* Copyright 2024 */"

Combine with your build script in package.json:

{
  "scripts": {
    "build": "tsc -b && minimize-js lib"
  }
}

Options

| Flag | Alias | Description | Default | |------|-------|-------------|---------| | --minifyWhitespace | -w | Remove all whitespace | true | | --minifyIdentifiers | -i | Shorten variable names | true | | --minifySyntax | -s | Collapse syntax patterns | true | | --minifyDeclaration | -d | Minify .d.ts files | false | | --banner <string> | -b | Prepend a string to each JS file | — |

Programmatic API

Use @minimize-js/core directly in your build scripts or tooling:

import { minimization } from '@minimize-js/core'

const results = minimization(['dist/index.js', 'dist/utils.js'], {
  minifyWhitespace: true,
  minifyIdentifiers: true,
  minifySyntax: true,
  minifyDeclaration: false,
  banner: '/* my lib v1.0.0 */',
})

Returns an array of results — no file I/O, no side effects, fully testable.

How It Works

your directory
      │
      ▼
  glob *.js
      │
      ├──▶  .js files  ──▶  esbuild transformSync  ──▶  write back
      │
      └──▶  .d.ts files ──▶  dts-minify  ──▶  write back

Shebang lines (#!/usr/bin/env node) are preserved automatically.

Contributing

Contributions are welcome. Fork → branch → PR.

git clone https://github.com/Randagio13/minimize-js
cd minimize-js
pnpm install
pnpm build
pnpm test

Commits follow Conventional Commits — this drives automatic versioning via Lerna.

feat: add new option
fix: handle edge case in shebang detection
chore: update deps

License

MIT — Alessandro Casazza

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