gistfile1.clj

(defn xhr
  [uri method content headers]
  (let [c (chan)
        m (mult c)]
    (if-let [cached (get-cached uri)]
      (let [tapped (tap m (chan))]
        (put! tapped cached)
        tapped)
      (if-let [source (get @outstanding-requests uri)]
        (tap source (chan))
        (try (.send xhr-pool uri uri method
                    (if (and (not (string? content))
                             (not (nil? content)))
                      (stringify content)
                      content)
                    (clj->js headers) 50
                    #(do (put! c (handle-response (.-target %)))
                         (swap! outstanding-requests dissoc uri))
                    0)
             (swap! outstanding-requests assoc uri m)
             (tap m (chan))
             (catch js/Error e nil))))))