CoffeeScript is a little language that compiles down to JavaScript. The syntax is inspired by Ruby and Python, and implements many features from those two languages. This book is designed to help you learn CoffeeScript, understand best practices and start building awesome client side applications.offeeScript is not limited to the browser, and can be used to great effect in server side JavaScript implementations, such as Node.js. Additionally, CoffeeScript is getting much wider use and integration, such as being a default in Rails 3.1.