It is, but pre-distribution it is compiled down to 100% JavaScript as a stand-alone JS lib that you can load with a script tag or NodeJS require(...).

The ClojureScript compiler only gets involved if you want to hack on mori yourself, as opposed to consuming it as a library.

If the point you're making is that it's implemented with ClojureScript as opposed to JavaScript, the fact is that everything that ClojureScript "does" you can do with hand-written JavaScript, but your hand-rolled solution might not be as generic or efficient (depending on your JS chops).