Scum example

core.cljs

(ns probe.core
  (:require-macros [cljs.core.async.macros :refer [go go-loop]])
  (:require [rum.core :as r]
            [scrum.core :as scrum]
            [probe.scrum.counter :as counter]))

(defonce reconciler
  (scrum/reconciler {:state       (atom {})
                     :controllers {:counter/state counter/counter-controller}}))
(defonce init-ctrl
  (scrum/broadcast-sync! reconciler :init))

(r/mount (counter/counter-ui reconciler)
         (js/document.getElementById "app"))

counter.cljs

(ns probe.scrum.counter
  (:require [rum.core :as rum]
            [scrum.core :as scrum]))

(rum/defc counter-ui < rum/reactive [r]
  [:div
   ; :counter here should be in sync with keyword in
   ; reconciler declaration -> =(
   [:button {:on-click #(scrum/dispatch! r ::state :dec)} "-"]
   [:span   (rum/react (scrum/subscription r [::state]))]
   [:button {:on-click #(scrum/dispatch! r ::state :inc)} "+"]])

(def initial-state 0)

(defmulti counter-controller (fn [action] action))
(defmethod counter-controller :init [] initial-state)
(defmethod counter-controller :inc [_ _ counter] (inc counter))
(defmethod counter-controller :dec [_ _ counter] (dec counter))