core.async 101

core-async-101.cljs

(comment
  ;This takes at most ~2000 ms to execute
  (let [process-seq-of-channels
        (fn [chans]
          (a/go
            (loop [chans chans]
              (if-not (empty? chans)
                (let [ch   (first chans)
                      resp (a/<! ch)]
                  (println resp)
                  (recur (rest chans)))
                (println :done)))))
        fake-http!
        (fn [req idx]
          (let [resp-ch (a/chan 1)]
            ;TODO Do HTTP request!!!
            (a/go
              (a/<! (a/timeout (rand-int 2000)))
              (a/put! resp-ch {:resp req :idx idx}))
            ;TODO end
            ;return channel
            resp-ch))]
    (a/go
      ;initiate requests, replace fake-http! with a function that makes an HTTP request and returns a channel
      ;MUST use (doall...) to send the requests right away!
      (let [resp-chans (doall (map fake-http! (repeat 10 {:req 1}) (range 10)))]
        (println :starting)
        (process-seq-of-channels resp-chans)))))