prettify

Author: lilactown

examples/workshop/state.cljs

@@ -4,6 +4,10 @@
             [hx.hooks :as hooks :refer [<-state <-effect <-context]]
             ["react" :as react]))
 
+;;
+;; A simple counter
+;;
+
 (defnc Simple [_]
   (let [state (<-state 0)]
     [:<>
@@ -13,6 +17,11 @@
 (dc/defcard simple
   (hx/f [Simple]))
 
+
+;;
+;; A timer that increments each second
+;;
+
 (defnc Timer
   [opts]
   (let [seconds (<-state 0)]
@@ -27,26 +36,43 @@
 (dc/defcard timer
   (hx/f [Timer]))
 
+
+;;
+;; Using React Context + Hooks for global state management
+;;
+
 (def app-state (react/createContext))
 
 (defnc App [{:keys [children]}]
-  (let [state (<-state {:counter 0})]
+  (let [state (<-state {})]
     [(.-Provider app-state) {:value state}
      children]))
 
-(defnc Counter [_]
+(defnc CounterConsumer [_]
   (let [state (<-context app-state)
         {:keys [counter]} @state]
     [:<>
      [:div "Counter: " counter]
      [:button {:on-click #(swap! state update :counter inc)} "inc"]]))
 
-(defnc PrintState [_]
+(defnc PrintStateConsumer [_]
   (let [state (<-context app-state)]
     [:pre (prn-str @state)]))
 
+(defnc TimerConsumer [_]
+  (let [state (<-context app-state)
+        {:keys [timer]} @state]
+    (<-effect (fn []
+                (let [id (js/setInterval #(swap! state update :timer inc) 1000)]
+                  (fn []
+                    (js/clearInterval id))))
+              [])
+    [:<>
+     [:div "Timer: " timer]]))
+
 (dc/defcard context
   (hx/f [App
-         [PrintState]
-         [Counter]]))
+         [PrintStateConsumer]
+         [TimerConsumer]
+         [CounterConsumer]]))