What is "coffeescript"

CoffeeScript is a programming language that transcompiles to JavaScript. It adds syntactic sugar inspired by Ruby, Python and Haskell in an effort to enhance JavaScript's brevity and readability. Specific additional features include list comprehension and pattern matching.

CoffeeScript support is included in Ruby on Rails version 3.1. In 2011, Brendan Eich referenced CoffeeScript as an influence on his thoughts about the future of JavaScript.