partition-chan.cljs

(defn partition-chan
  ([start-pred in] (partition-chan start-pred (complement start-pred) in))
  ([start-pred end-pred in]
     (let [out (chan)]
       (go
        (loop []
          (if-let [val (<! in)]
            (if (start-pred val)
              (let [next-chan (chan)]
                (>! out next-chan)
                (>! next-chan val) ;; capture the first message
                (<! (tap-until end-pred in next-chan))
                (close! next-chan)
                (recur)))
            (close! out))))
       out)))