Clojurescript browser event handler debouncing (via core.async) - window-based approach.

debounced-by-window.cljs

;; window-based debounce
;; (passes the existing timer through on recur)
(defn debounce [ms somefunc]
  (let [in (chan)
        out (chan)]
    ; debounce in channel - based on https://gist.github.com/scttnlsn/9744501
    (go-loop [last-val nil
              timer (timeout ms)]
      (let [val (if (nil? last-val) (<! in) last-val)
            [new-val ch] (alts! [in timer])]
        (condp = ch
          timer (do (>! out val) (recur nil (timeout ms)))
          in (if new-val (recur new-val timer) (close! out)))))

    ; call debounced function on the given function/handler
    (go-loop []
       (let [val (<! out)]
         (somefunc val)
         (recur)))

    ;return in event channel
    in))