Merge pull request mobxjs#1 from mohsen1/patch-1

Use `this` in AppState constructor for updating timer

Author: mweststrate

src/index.tsx

@@ -11,7 +11,7 @@ class AppState {
 
     constructor() {
         setInterval(() => {
-            appState.timer += 1;
+            this.timer += 1;
         }, 1000);
     }
 
@@ -39,4 +39,4 @@ class TimerView extends React.Component<{appState: AppState}, {}> {
 };
 
 const appState =  new AppState();
-ReactDOM.render(<TimerView appState={appState} />, document.getElementById('root'));
+ReactDOM.render(<TimerView appState={appState} />, document.getElementById('root'));