Filter Example; Pub Sub Example

filter.cljs

(ns boston.core
  (:require [cljs.core.async :as async :refer [chan <! >! merge timeout filter<]])
  (:require-macros [cljs.core.async.macros :as m :refer [go-loop go]]))


(enable-console-print!)

(def in-channel-one (chan))
(def in-channel-two (chan))
(def in-channel-three (chan))

(defn randomly-constantly [c cid]
  (go-loop []
    (<! (timeout (* 1000 (rand-int 4))))
    (>! c (+ (* 10 cid) (rand-int 10)))
    (recur)))

(randomly-constantly in-channel-one   1)
(randomly-constantly in-channel-two   2)
(randomly-constantly in-channel-three 3)

(def out-channel
  (merge [in-channel-one
          in-channel-two
          in-channel-three]))

(defn filter-odds [c]
  (filter< even? c))

(def only-evens
  (filter-odds out-channel))

(go-loop []
  (println (<! only-evens))
  (recur))

pubsub.cljs

(ns boston.core
  (:require [cljs.core.async :as async :refer [chan <! >! merge timeout pub sub]])
  (:require-macros [cljs.core.async.macros :as m :refer [go-loop go]]))


(enable-console-print!)


(def pub-channel (chan))
(def sub-channel (chan))

(def publication
  (pub pub-channel (fn [v] (:topic v))))

; sub channel listens to topic :sausages
(sub publication :sausages sub-channel)


(defn randomly-constantly [c]
  (go-loop []
    (<! (timeout (* 1000 (rand-int 4))))
    (let [output { :topic (if (even? (rand-int 2)) :sausages :not-sausages)
                   :value (rand-int 10) }]
      (println "Generated " output)
      (>! c output))
    (recur)))

(randomly-constantly pub-channel)

(go-loop []
  (println (<! sub-channel))
  (recur))