There (kind of) is another option. It is called Rescript. But to be honest will probably never take off... :( For me it has by far the best type system for a script language. It is based on Ocaml. Its syntax is easier to read than Ocaml and as powerful as Ocaml if not more by aiming at JS world. One great feature you can take a look at to see how simple and powerful the type system is is Pattern Matching / Destructuring [1] and its "switch".

https://rescript-lang.org/

[1] https://rescript-lang.org/docs/manual/latest/pattern-matchin...