(defn js->clj
  "Recursively transforms JavaScript arrays into ClojureScript
  vectors, and JavaScript objects into ClojureScript maps.  With
  option ':keywordize-keys true' will convert object fields from
  strings to keywords."
  ([x] (js->clj x :keywordize-keys false))
  ([x & opts]
    (let [{:keys [keywordize-keys]} opts
          keyfn (if keywordize-keys keyword str)
          f (fn thisfn [x]
              (cond
                (satisfies? IEncodeClojure x)
                (-js->clj x (apply array-map opts))

                (seq? x)
                (doall (map thisfn x))

                (map-entry? x)
                (MapEntry. (thisfn (key x)) (thisfn (val x)) nil)

                (coll? x)
                (into (empty x) (map thisfn) x)

                (array? x)
                (persistent!
                 (reduce #(conj! %1 (thisfn %2))
                         (transient []) x))

                (identical? (type x) js/Object)
                (persistent!
                 (reduce (fn [r k] (assoc! r (keyfn k) (thisfn (gobject/get x k))))
                         (transient {}) (js-keys x)))
                :else x))]
      (f x))))