Decaf JS

0.6.2 verified Fri May 01 auth: no javascript maintenance

A CoffeeScript to ES6 transpiler that leverages the CoffeeScript compiler to produce modern JavaScript syntax. Stable version 0.6.2 is available on npm. Unlike other transpilers, Decaf uses the official CoffeeScript parser to build an AST and then maps it to ES6 constructs, falling back to original CoffeeScript output for unsupported syntax. It can be used as a CLI tool or as a Node module with jscodeshift for code transforms. Development appears to be in maintenance mode with limited recent updates.

Common errors

error Error: Cannot find module 'coffee-script' ↓

cause Missing peer dependency coffee-script / coffeescript.

fix

Install: npm install coffeescript (or coffee-script for older versions).

error TypeError: decaf.compile is not a function ↓

cause Incorrect import/require: probably using import or destructuring.

fix

Use: const decaf = require('decafjs'); decaf.compile(...);

error SyntaxError: Unexpected token while parsing CoffeeScript ↓

cause Input contains unsupported CoffeeScript syntax or invalid input.

fix

Check source for syntax errors; Decaf falls back to original CoffeeScript output, but invalid syntax will still break.

Warnings

gotcha The package name on npm is 'decafjs', not 'decaf'. Using 'npm install decaf' installs a different unrelated package. ↓

fix Install with 'npm install decafjs'.

gotcha The exported object is the compile function itself; you cannot destructure named exports like { compile }. ↓

fix Use: const decaf = require('decafjs'); then decaf.compile(...).

deprecated Package has not been updated since 2018; may not support latest CoffeeScript or ES6 features. ↓

fix Consider alternatives like decaffeinate (more actively maintained).

gotcha When used as CLI globally, command is 'decaf' not 'decafjs'. Ensure global install. ↓

fix Run: npm install -g decafjs; then decaf <file or directory>.

Install

npm install decafjs

yarn add decafjs

pnpm add decafjs

Imports

default
wrong
```
import decaf from 'decafjs';
```
correct
```
const decaf = require('decafjs');
```
Package does not provide ES module exports; use CommonJS require.

compile

wrong

import { compile } from 'decafjs';

correct

const decaf = require('decafjs'); decaf.compile('()-> alert "hello"');

The module exports a single function object; compile is a property, not a named export.

compileFile

wrong

const { compileFile } = require('decafjs');

correct

const decaf = require('decafjs'); decaf.compileFile('file.coffee');

Not available as named export; the main default export contains all methods.

Quickstart

Demonstrates basic usage: compile CoffeeScript string and file to ES6 JavaScript using Decaf.

const decaf = require('decafjs');
const path = require('path');
const fs = require('fs');

// Compile a CoffeeScript string to ES6 JS
const coffeeCode = 'square = (x) -> x * x';
const es6Code = decaf.compile(coffeeCode);
console.log(es6Code); // outputs: var square = (x) => x * x;

// Compile a file (assuming example.coffee exists)
const filePath = path.join(__dirname, 'example.coffee');
const coffeeFromFile = fs.readFileSync(filePath, 'utf8');
const jsFromFile = decaf.compile(coffeeFromFile, { tabWidth: 2 });
fs.writeFileSync('example.js', jsFromFile);
console.log('Compiled successfully!');