time

macrosince v0.0-927 clojure.core/timeEdit
(time expr)

Source docstring:
Evaluates expr and prints the time it took. Returns the value of expr.
Source code @ clojurescript:src/main/clojure/cljs/core.cljc
(core/defmacro time
  [expr]
  `(let [start# (system-time)
         ret# ~expr]
     (prn (cljs.core/str "Elapsed time: "
            (.toFixed (- (system-time) start#) 6)
            " msecs"))
     ret#))