Counter w/ ClojureScript and Om

counter.cljs

(ns counter.core
  (:require [om.core :as om :include-macros true]
            [om.dom :as dom :include-macros true]))

(enable-console-print!)

(def app-state (atom {:count 42}))

(defn dec-button [counter owner]
  (reify
    om/IRender
    (render [this]
      (dom/button #js {:onClick (fn [e] (om/transact! counter :count dec))}
                  "dec"))))

(defn inc-button [counter owner]
  (reify
    om/IRender
    (render [this]
      (dom/button #js {:onClick (fn [e] (om/transact! counter :count inc))}
                  "inc"))))

(defn counter [app owner]
  (reify
    om/IRender
    (render [this]
      (let [count (:count app)]
        (dom/div nil
                 (dom/h1 nil count)
                 (om/build dec-button app)
                 (om/build inc-button app))))))

(om/root
  counter
  app-state
  {:target (. js/document (getElementById "app"))})