> Frontend there is that ReasonML/Reason/ReScript thing that Facebook it trying to do. It offers an alternative syntax but nearly nobody uses it because they changed the name and I think also the syntax three times already. So it is all a mess.

"Nobody" uses ReasonML / Reason.

Plenty of people use ReScript.

I wasn't a big fan of the ReScript split, but I think by now it's unfair to speak of these as if they're one community with a confusing story. I think it's very fair to say it's now two separate communities: ReScript and OCaml. It was very confusing for a while, but by now it actually is much easier to understand than before the ReScript split:

ReScript is really its own language now. The compiler for that language just happens to still understand OCaml syntax, for now. The ReScript language and community is focused on the JS ecosystem, with readable JS output.

OCaml has js_of_ocaml. JSOO compiles OCaml to JS, so it's focused on the OCaml ecosystem. The JS output is not readable but you can build "any" OCaml program.

Really that's the main story -- not so hard to grasp?

There is also melange, but that's a relatively new effort in the OCaml community (attracting OCaml-y refugees from ReScript) whose status I haven't formed a view on yet. The idea is to compile OCaml programs to readable JS. Reason used to do that, but Reason now only has a tiny community (and I believe it now uses JSOO?). ReScript still does that, but using it for that purpose is no longer supported.