cljs.repl.nashorn/create-engine

(defn create-engine
      ([] (create-engine nil))
      ([{:keys [code-cache] :or {code-cache true}}]
       (let [args (when code-cache ["-pcc"])
             factories (.getEngineFactories (ScriptEngineManager.))
             factory (get (zipmap (map #(.getEngineName %) factories) factories) "Oracle Nashorn")]
         (if-let [engine (if-not (empty? args)
                           (.getScriptEngine ^ScriptEngineFactory factory (into-array args))
                           (.getScriptEngine ^ScriptEngineFactory factory))]
           (let [context (.getContext engine)]
             (.setWriter context *out*)
             (.setErrorWriter context *err*)
             engine)
           (throw (IllegalArgumentException.
                    "Cannot find the Nashorn script engine, use a JDK version 8 or higher."))))))