What is coffeescript?

jashkenas/coffeescript — explained in plain English

Analysis updated 2026-06-24

★ 16,577CoffeeScriptAudience · developerComplexity · 2/5Setup · easy

Mindmap

mindmap
  root((repo))
    What it does
      Compiles to JavaScript
      Cleaner syntax
      Runs anywhere JS runs
    How to use
      npm install
      coffee command
      Compile with -c flag
    Use cases
      Node.js scripting
      Browser JS authoring
      Existing JS projects
    Audience
      JavaScript developers
      Node.js users

mindmap root((repo)) What it does Compiles to JavaScript Cleaner syntax Runs anywhere JS runs How to use npm install coffee command Compile with -c flag Use cases Node.js scripting Browser JS authoring Existing JS projects Audience JavaScript developers Node.js users

Click or tap to explore — scroll the page freely

What do people build with it?

USE CASE 1

Write a Node.js script in CoffeeScript syntax and compile it to JavaScript for deployment without changing your runtime.

USE CASE 2

Add CoffeeScript to an existing project via npm so your team can author in CoffeeScript while shipping standard JS files.

USE CASE 3

Run a CoffeeScript file directly with the coffee command during development, skipping the compile step entirely.

What is it built with?

CoffeeScriptJavaScriptNode.jsnpm

How does it compare?

	jashkenas/coffeescript	dropbox/zxcvbn	mojs/mojs
Stars	16,577	15,958	18,701
Language	CoffeeScript	CoffeeScript	CoffeeScript
Setup difficulty	easy	easy	easy
Complexity	2/5	2/5	2/5
Audience	developer	developer	developer

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 5min

License information is not mentioned in the explanation.

So what is it?

CoffeeScript, described in its own README as "a little language that compiles into JavaScript" and in its tagline as "unfancy JavaScript", is a programming language whose source files are translated by a compiler into ordinary JavaScript code that can then run anywhere JavaScript runs. The tool is installed through npm, either locally to a single project or globally so the coffee command is available everywhere, and it requires Node.js. Once installed, the coffee command can either run a .coffee script directly or compile it into a .js file with the -c flag. Someone would use it if they prefer CoffeeScript's syntax over plain JavaScript but still need standard JavaScript as the final output. The full documentation and examples live at coffeescript.org.

Copy-paste prompts

Prompt 1

I prefer CoffeeScript syntax over plain JavaScript. Show me how to install jashkenas/coffeescript globally via npm and compile a hello-world .coffee file to .js.

Prompt 2

What are the most useful CoffeeScript features compared to modern JavaScript? Give me side-by-side examples of classes, arrow functions, and destructuring in both languages.

Prompt 3

I have a Node.js project and want to add CoffeeScript support. Show me how to install it as a dev dependency and set up an npm build script that compiles all .coffee files to a dist/ folder.

Prompt 4

How do I run a CoffeeScript file directly without compiling it first, and how do I pass command-line arguments to it?

Frequently asked questions