Does the CLJS repl work with/in emacs?

Can it? It never does for me

yes

assuming you’re using cider

you can either use cider-jack-in-clojurescript if you’re using a nrepl cljs repl or (I think) create-sibling-repl when you already have an nrepl clojure repl open

if you’re using figwheel, follow the directions on https://github.com/bhauman/lein-figwheel/wiki/Using-the-Figwheel-REPL-within-NRepl this page

near the bottom, search for CIDER

that’s what I’ve done and it just works