You are right, and I considered adding that question as well. JavaScript has so many quirks that it's very tempting to use a transpiler. However I do not have any experience with transpilers myself. I also don't see any of them getting a lot of traction, not even CoffeeScript. And then there are people moving towards vanilla JavaScript. It is definitely an important question.
TypeScript, AtScript, Dart - now every serious web app builder provides at least one.