debounce an action on a channel for values that produce the same result of a key-fn

debounce.clj

(defn debounce
  "debounce an action on a channel for values that produce the same result of a key-fn"
  ([f input-ch wait] (debounce f input-ch wait identity))
  ([f input-ch wait key-fn]
   ;; keep a map of keys that have been triggered
   (go-loop [debounced {}]
     (let [[v c] (alts! (conj (vals debounced) input-ch))]
       (if (= c input-ch)
         (let [key (key-fn v)]
           (if (get (into #{} (keys debounced)) key) ;; if our key is debounced
             (recur debounced) ;; don't do anything
             (recur (assoc debounced ;; add key to rebounced
                           key (go ;; go immediately returns a channel
                                 (<! (timeout wait));; after wait returning key puts key onto the cannel
                                 key)))))