CoffeeScript is a little language that compiles into JavaScript. It is an attempt to expose the good parts of JavaScript in a simple way and friendly syntax, the golden rule being: “It’s just JavaScript”.

The code compiles one-to-one into the equivalent JavaScript, and there is no interpretation at runtime. The compiled output is readable and pretty-printed, will work in every JavaScript runtime, and tends to run as fast or faster than the equivalent handwritten JavaScript.