reduce-example.clj

(require '[clojure.core.async :as ca])

(def some-ch (ca/chan))
(def result-ch (ca/reduce 
                 (fn [xs msg] 
                   (if (= msg :done)                     
                     (reduced xs)
                     (conj xs msg)))
                   []
                   some-ch))
(ca/put! some-ch :a)
(ca/put! some-ch :b)
(ca/put! some-ch :done)
(ca/<!! result-ch) ;;[:a :b]
(ca/put! some-ch :c)
(ca/<!! some-ch) ;; :c