CoffeeScript
From Just Solve the File Format Problem
CoffeeScript is a programming language designed as an advance on JavaScript, "without its quirky corners." It is run through a script that transforms it into JavaScript so that it runs in any modern browser.
Source files use the extension .coffee. CoffeeScript also supports literate programming. Literate CoffeeScript files end in .litcoffee.
According to the State of JavaScript 2016 survey, CoffeeScript use and favorability is in decline among JS developers as JavaScript ES6, JSX, and TypeScript are on the rise.
