Lots of Rails developers. I made a conscious decision to introduce CoffeeScript at me work some years ago, because my experience had been that when back-end programmers dabble in Javascript ("The front-ender is busy, but hey, this seems simple enough. I'll just do it myself"), they make horrible messes because they are unfamiliar with all off vanilla JS's quirks and design mistakes (implicit global, to name one). CoffeeScript protects them from making these kind of mistakes/

I am a backend developer working in Ruby. As a senior programmer I sometimes have to help juniors on the frontend side. When I need to write frontend JS, I still often write Coffeescript, compile it and copy paste the resulting JS as "my code". I haven't had the time to look in ES6 and newer JS technologies, but at least I know that the JS I provide follows most good practices.

I'd like to reply to both of you. I like CoffeeScript mainly because it's so similar to Ruby and convenient to use. I have not thought about using the "raw generated js". How does it work for you ?

What if you would choose to work with something like React or Ember ?