There are some libraries for ATS, but it's not a well known language so there is not too many out there. ATS makes it easy to mix C by embedding it within ATS,

There are some libraries for ATS, but it's not a well known language so there is not too many out there. ATS makes it easy to mix C by embedding it within ATS, and defining an interface that makes it harder to unsafely use the C API. Since it's so easy most people probably just do this when they need a C library. There are wrappers for libevent which I've used for the network side of long running server side programs in ATS in this manner. With regards to "Does it compile to JS", the answer is yes. There are backends for different languages, JS being one of them. There's also PHP and Erlang backends IIRC.