I still use CoffeeScript for every game I make [1]. I know it's very passée but every time I rewrite something from javascript it turns out to be much shorter and more readable. It's true that there is now many improvements available compared to ES5 times but for me CoffeeScript still has a lot to offer. I admit, it's mostly ergonomics, but the cost of compilation is so minuscule that I find it worthwhile.

[1] https://redka.games