Every single one of these compile to the JavaScript runtime.

(Dart has a native VM in Chromium, but AFAIK it is a long way off from the real world)

Right and ClojureScript, for example, has full goroutines in it (i.e. core.async) if doing standard callback based async in JS isn't your thing.

Functionally, it makes little to no difference whether you're writing something that compiles down to JS or writing something that compiles down to its own runtime (assuming you turn source maps on your browser).

>Functionally, it makes little to no difference whether you're writing something that compiles down to JS or writing something that compiles down to its own runtime (assuming you turn source maps on your browser).

It actually makes a big difference. You can't use profiles, debugger, libraries, and other stuff which is platform specific but have to use JavaScript ones. Often, they don't play well with with languages which generate to JS.

That doesn't change the fact they use the JavaScript runtime, which was the question the parent was trying to address.