The repository is 95% OCaml, 3.9% cpp, 1.0% other mate.

I recommend clicking the link next time.

There may be javascript in the build system somewhere, but (correct me if I'm wrong) this appears to be leveraging the ocaml toolchain as a backend for reasonml rather than javascript.

In fact, revery is written pretty much entirely in ocaml. It appears to allow you to write reasonml as if you're writing for react/electron, but in fact it's compiled to native code with an included gui library managed for you.

Yes it's the same problem. But it's not JavaScript.

You can learn JavaScript, promise me!