fix: add alesanderlopez's fix

Kerumen#9

Author: yeewong

src/Counter.js

@@ -25,10 +25,23 @@ export default class Counter extends Component {
 
   componentDidMount() {
     this.startTime = Date.now();
+    this.umount = false
+    requestAnimationFrame(this.animate.bind(this));
+  }
+
+  componentWillUnmount() {
+    this.umount = true
+  }
+
+  reset() {
+    this.startTime = Date.now();
+    this.stop = false
     requestAnimationFrame(this.animate.bind(this));
   }
 
   animate() {
+    if (this.umount) return;
+
     const { onComplete } = this.props;
 
     if (this.stop) {
@@ -60,4 +73,4 @@ export default class Counter extends Component {
       <Text style={style}>{value.toFixed(digits)}</Text>
     );
   }
-}
+}