Autosave feature

- prevents losing state when app is accidentally closed

src/app/autosave.cljs

@@ -0,0 +1,51 @@
+(ns app.autosave
+  (:require
+   [re-frame.core :as re-frame]
+   [clojure.edn :as edn]))
+
+(defn init [autosave-key]
+  (re-frame/reg-cofx
+   ::autosave
+   (fn [coeffects _]
+     (assoc coeffects
+            :autosave
+            (edn/read-string
+             (js/window.localStorage.getItem autosave-key)))))
+
+  (re-frame/reg-fx
+   ::autosave
+   (fn [db]
+     (js/window.localStorage.setItem autosave-key (pr-str db))))
+
+  (re-frame/reg-fx
+   ::autosave-remove
+   (fn [_]
+     (js/window.localStorage.removeItem autosave-key)))
+
+  (re-frame/reg-event-fx
+   ::autosave
+   (fn [{:keys [db]}]
+     {::autosave db}))
+
+  (re-frame/reg-event-fx
+   ::autosave-remove
+   (fn [_]
+     {::autosave-remove nil}))
+
+  (re-frame/reg-event-fx
+   ::autosave-load
+   [(re-frame/inject-cofx ::autosave)]
+   (fn [cofx]
+     (if-let [autosave (:autosave cofx)]
+       {:db autosave
+        ::autosave-remove nil}
+       {})))
+
+  (re-frame/dispatch [::autosave-load])
+  (js/document.addEventListener
+   "visibilitychange"
+   (fn []
+     (case (.-visibilityState js/document)
+       "visible" (re-frame/dispatch [::autosave-remove])
+       "hidden" (re-frame/dispatch [::autosave])
+       nil))))

src/app/core.cljs

@@ -4,7 +4,8 @@
    [reagent.dom :as reagent-dom]
    [app.config :as config]
    [app.views :as views]
-   [app.events :as events]))
+   [app.events :as events]
+   [app.autosave :as autosave]))
 
 (defn mount-root []
   (re-frame/clear-subscription-cache!)
@@ -42,6 +43,7 @@
   (dev-setup)
   (prod-setup)
   (prevent-screen-lock)
+  (autosave/init "nenadalm.life-counter/autosave")
   (re-frame/dispatch-sync [::events/init])
   (mount-root))
 

src/app/events.cljs

@@ -121,11 +121,13 @@
  [(re-frame/inject-cofx :app-version)
   (re-frame/inject-cofx :settings)
   (re-frame/inject-cofx :profiles)]
- (fn [{:keys [app-version settings profiles]} _]
-   (let [db (reset-game {:settings (merge default-settings settings)
-                         :profiles (if (seq profiles) profiles default-profiles)
-                         :app-info {:version app-version}})]
-     (cond-> {:db db
+ (fn [{:keys [app-version settings profiles db]} _]
+   (let [data {:settings (merge default-settings settings)
+               :profiles (if (seq profiles) profiles default-profiles)
+               :app-info {:version app-version}}]
+     (cond-> {:db (if (seq db)
+                    (merge db data)
+                    (reset-game data))
               :update-time 1000}
        (not= profiles (:profiles db)) (assoc :profiles (:profiles db))))))