[mrspeaker]

I'd argue that CoffeeScript was dead before Typescript went mainstream, and that JavaScript killed CoffeeScript: or rather, CoffeeScript killed itself.

Many of the features that made CoffeeScript fun and useful were incorporated directly into ES6. The proposals even cited CoffeeScript and borrowed the syntax verbatim or with minor changes. By the time arrow-functions were accepted it was obvious that the cost of transpiling wasn't worth it any more, all that was left was "significant whitespace", which was the most buggy part about CoffeeScript anyway!

[dtagames]

The whole purpose of Typescript is to be an early release of the next version of JS, so everything in TS will eventually be in JavaScript.

I think CoffeeScript died because it didn't offer any real improvement, which TS offers even incrementally (in a single function, for example) without going all-in.

[stop50]

The most popular piece that used coffeescript was atom and github recently killed it in favour of vscode, written in typescript afaik.