It looks like (apply my-multimethod 1 2 3) tries to call the JavaScript apply on the multimethod, which gives
Uncaught TypeError: Object [object Object] has no method 'apply'
ClojureScript compiler cf0e9bc
Fixed, https://github.com/clojure/clojurescript/commit/f183f7967c8b81e65735d0bb8f2addcdf9071a63
Minor
MinorMinor
It looks like (apply my-multimethod 1 2 3) tries to call the JavaScript apply on the multimethod, which gives
Uncaught TypeError: Object [object Object] has no method 'apply'