diff --git a/src/index.tsx b/src/index.tsx
index f82c1df..66d9059 100644
--- a/src/index.tsx
+++ b/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'));
\ No newline at end of file
+ReactDOM.render(<TimerView appState={appState} />, document.getElementById('root'));