@gasket/cjs

Utility for transpiling ESM to CJS with .cjs extensions

Installation

pnpm install @gasket/cjs

Usage

CLI

# Transpile from ./lib to ./cjs (default)
gasket-cjs

# Transpile from custom source directory
gasket-cjs ./src

# Transpile to custom output directory
gasket-cjs ./src ./dist/cjs

Programmatic API

import { transpile } from '@gasket/cjs';

// Basic usage
const result = await transpile('./src', './cjs');

// With options
const result = await transpile('./src', './cjs', {
  extensions: ['.js', '.mjs', '.ts'],
  createPackageJson: true,
  onProgress: ({ file, current, total }) => {
    console.log(`Processing ${file} (${current}/${total})`);
  }
});

console.log(`Transpiled ${result.successful.length} files`);

Configuration

The utility uses SWC for transpilation with the following default configuration:

• Module type: CommonJS
• Target: ES2020
• Extensions: .js, .mjs
• Output extension: .cjs

Features

• ✅ Transpiles ESM to CJS using SWC
• ✅ Changes file extensions from .js/.mjs to .cjs
• ✅ Fixes import paths to use .cjs extensions
• ✅ Creates package.json in output directory
• ✅ Preserves directory structure
• ✅ CLI and programmatic interfaces
• ✅ Progress reporting

API Reference

transpile(sourceDir, outputDir, options)

Main transpilation function.

Parameters

• sourceDir (string): Source directory path
• outputDir (string, optional): Output directory path (default: 'cjs')
• options (object, optional): Configuration options

Options

• swcConfig (object): Custom SWC configuration
• extensions (string[]): File extensions to process (default: ['.js', '.mjs'])
• createPackageJson (boolean): Create package.json in output dir (default: true)
• onProgress (function): Progress callback function

Returns

Promise resolving to TranspileSummary object:

{
  successful: TranspileResult[],
  failed: TranspileResult[],
  total: number,
  outputDir: string
}

License

MIT licensed.