cljs.test/js-filename

(defn js-filename [stack-element]
  (let [output-dir (cljs.test/cljs-output-dir)
        output-dir (cond-> output-dir
                     (not (string/ends-with? output-dir "/"))
                     (str "/"))]
    (-> (.split stack-element output-dir)
      last
      (.split ":")
      first)))