I can say what I do use Bash for: create files & directories, and simple string replacements in files. Anything more involved goes into a proper program. Usually OCaml, though I can fall back to more mainstream languages (Python, C) if I need a wide audience to be able to read it, and the program is simple enough that types aren't really a problem to begin with.

Javascript is for scripts that fit in one file. Anything else is typescripy.