Adding .remove() method to FCM.on() (#263)

* fixed documentation

* added .unsubscribe() method

* fix

* fix

* remove instead of unsubscribe

README.md

@@ -268,7 +268,7 @@ class App extends Component {
             console.log(token)
             // store fcm token in your server
         });
-        this.notificationUnsubscribe = FCM.on('notification', (notif) => {
+        this.notificationListener = FCM.on('notification', (notif) => {
             // there are two parts of notif. notif.notification contains the notification payload, notif.data contains data payload
             if(notif.local_notification){
               //this is a local notification
@@ -277,16 +277,16 @@ class App extends Component {
               //app is open/resumed because user clicked banner
             }
         });
-        this.refreshUnsubscribe = FCM.on('refreshToken', (token) => {
+        this.refreshTokenListener = FCM.on('refreshToken', (token) => {
             console.log(token)
             // fcm token may not be available on first load, catch it here
         });
     }
 
     componentWillUnmount() {
-        // prevent leaking
-        this.refreshUnsubscribe();
-        this.notificationUnsubscribe();
+        // stop listening for events
+        this.notificationListener.remove();
+        this.refreshTokenListener.remove();
     }
 
     otherMethods(){

index.js

@@ -73,12 +73,9 @@ FCM.on = (event, callback) => {
     const nativeEvent = eventsMap[event];
     if (!nativeEvent) {
         throw new Error('FCM event must be "refreshToken" or "notification"');
-    }
-    const listener = DeviceEventEmitter.addListener(nativeEvent, callback);
-
-    return function remove() {
-        listener.remove();
     };
+    
+    return DeviceEventEmitter.addListener(nativeEvent, callback);
 };
 
 FCM.subscribeToTopic = (topic) => {