Javascript merger function CLI (func-marger)

A fast JavaScript/TypeScript function packaging tool using Babel AST and Terser. It merges function declarations across multiple files and directories into a unified JavaScript Class containing static methods.

Features

• 📦 Directory & File Merging: Recursively scans and collects .js, .mjs, .cjs, .ts, and .tsx files.
• ⚡ Static Class Generation: Packs standalone function exports into static class methods.
• 🗜️ Built-in Terser Minification: Supports production-ready code compression (--minify).
• 🗺️ Chained Source Maps: Generates precise .map files across AST transformations and minification passes (--sourcemap).

Installation

# Global installation
npm install -g @leonardwoo/func-marger

# Or locally within your project
npm install --save-dev @leonardwoo/func-marger

CLI Usage

func-marger <output> <input...> [options]

Options

| Flag | Short | Default | Description | | :--- | :--- | :--- | :--- | | --class <name> | | Demo | Specify the generated class name | | --minify | -m | false | Enable code compression | | --banner | -b | false | Prepend copyright banner generated from package.json | | --sourcemap | -s | false | Generate source maps (.map) along with the output file | | --version | -v | | Print CLI version and exit |

CLI Examples

# 1. Merge an entire directory into a class
func-marger dist/Utils.js src/methods/ --class MyUtils

# 2. Mix directories and individual files
func-marger dist/Utils.js src/methods/ src/string.js --class AppTools

# 3. Production build with minification and source map generation
func-marger dist/Utils.min.js src/methods/ --class AppTools --minify --sourcemap

Programmatic API (Node.js)

You can import and use mergeFunctions directly in your Node.js scripts or build tools.

import { mergeFunctions } from "@leonardwoo/func-marger";

const files = ["./src/math.js", "./src/string.js"];

// Execution returns an object containing 'code' and 'map'
const { code, map } = await mergeFunctions(files, "MyUtils", {
  minify: true,
  sourcemap: true,
  outputPath: "dist/MyUtils.min.js",
});

console.log(code);

API Options

interface MergeOptions {
  minify?: boolean;     // Enable Terser code minification (default: false)
  sourcemap?: boolean;  // Generate Source Map (default: false)
  outputPath?: string;  // Target file path used for sourcemap linkage
}

Example Transformation

Input

src/math.js

export async function add(a, b) {
  return a + b;
}

src/string.js

export function* generateTags(str) {
  yield str.toUpperCase();
  yield str.toLowerCase();
}

Output

class AppTools {
  static async add(a, b) {
    return a + b;
  }
  static *generateTags(str) {
    yield str.toUpperCase();
    yield str.toLowerCase();
  }
}

License

MIT