From c42ac8fac48f9d56b54af4818917082fda9af21e Mon Sep 17 00:00:00 2001
From: Shin'ya Ueoka <ueokande@i-beam.org>
Date: Thu, 14 Sep 2017 21:14:13 +0900
Subject: [PATCH] improve store and reducers

---
 src/background/index.js |  8 +++-----
 src/reducers/index.js   |  7 +++++++
 src/store/index.js      | 21 +++++++++++++++++++--
 3 files changed, 29 insertions(+), 7 deletions(-)
 create mode 100644 src/reducers/index.js

diff --git a/src/background/index.js b/src/background/index.js
index 0c3adce..e9757b9 100644
--- a/src/background/index.js
+++ b/src/background/index.js
@@ -2,12 +2,12 @@ import * as keys from './keys';
 import * as inputActions from '../actions/input';
 import * as operationActions from '../actions/operation';
 import backgroundReducers from '../reducers/background';
+import reducers from '../reducers';
 import commandReducer from '../reducers/command';
 import inputReducers from '../reducers/input';
 import * as store from '../store'
 
-const emptyReducer = (state) => state;
-const emptyStore = store.createStore(emptyReducer, (e) => {
+const backgroundStore = store.createStore(reducers, (e) => {
   console.error('Vim-Vixen:', e);
 });
 let inputState = inputReducers(undefined, {});
@@ -27,9 +27,7 @@ const keyQueueChanged = (sender, prevState, state) => {
     return Promise.resolve();
   }
   let action = keys.defaultKeymap[matched];
-  emptyStore.dispatch(operationActions.exec(action, sender), (e) => {
-    console.error('Vim-Vixen:', e);
-  });
+  backgroundStore.dispatch(operationActions.exec(action, sender));
   return handleMessage(inputActions.clearKeys(), sender).then(() => {
     return backgroundReducers(undefined, action, sender).then(() => {
       return browser.tabs.sendMessage(sender.tab.id, action);
diff --git a/src/reducers/index.js b/src/reducers/index.js
new file mode 100644
index 0000000..d49af7d
--- /dev/null
+++ b/src/reducers/index.js
@@ -0,0 +1,7 @@
+const defaultState = {
+};
+
+export default function reducer(state = defaultState/*, action = {}*/) {
+  return Object.assign({}, state, {
+  });
+}
diff --git a/src/store/index.js b/src/store/index.js
index bcb65d6..841fd17 100644
--- a/src/store/index.js
+++ b/src/store/index.js
@@ -3,21 +3,38 @@ class Store {
     this.reducer = reducer;
     this.catcher = catcher;
     this.state = this.reducer(undefined, {});
+    this.subscribers = [];
   }
 
   dispatch(action) {
     if (action instanceof Promise) {
       action.then((a) => {
-        this.state = this.reducer(this.state, a);
+        this.transitNext(a);
       }).catch(this.catcher)
     } else {
       try {
-        this.state = this.reducer(this.state, action);
+        this.transitNext(action);
       } catch (e) {
         this.catcher(e);
       }
     }
   }
+
+  getState() {
+    return this.state;
+  }
+
+  subscribe(callback) {
+    this.subscribers.push(callback);
+  }
+
+  transitNext(action) {
+    let newState = this.reducer(this.state, action);
+    if (JSON.stringify(this.state) !== JSON.stringify(newState)) {
+      this.state = newState;
+      this.subscribers.forEach(f => f.call())
+    }
+  }
 }
 
 const empty = () => {};