If you already have everything working for clojure you can just turn clojure-mode
on for the current buffer using
M-x clojure-mode
If you want it turned on automatically you need to add an entry to the Auto Mode AList. In my case, adding the following to init.el
did the trick:
(add-to-list 'auto-mode-alist '("\.cljs$" . clojure-mode))
After that you need to reload your init.el
(M-x load-file
) and re-open the file.