Should (prn my-map) be doing a pretty print in console? mine doesn't...

Hi, I have cljs-devtools installed, I get the notification in the console that `:formatters` is active, and I sometimes see colored, formatted clojure data structures, but I was hoping that when I do `(prn my-map)` within some cljs source file, that would justify and color a large map. I'm just getting a regular print of the datastructure in the console, same as when cljs-devtools is not active. Am I doing something wrong? Thanks.