The idea that you can write your code in a language or language variant that compiles down to JavaScript may seem obvious now, but it's easy to forget how innovative it really is.

For the longest time CoffeeScript was the lone proponent of that strategy, but today it's been overtaken by ES6 and its follow-ups, TypeScript, Flow, and even languages with very different syntaxes such as Elm and Reason.

And there're good reasons to think that this is the future of JavaScript as a whole. With projects like Web Assembly arriving on the scene, writing code directly in JavaScript might soon seem quaint as developers embrace languages like Rust instead.

But until that time, the two big winners here are ES6 and TypeScript. Keep an eye out on Reason as well, which has Facebook's support and boasts both very high satisfaction and interest rates.