generic_push_notification.ts

// goal is to be able to extend the notification payload type depending on the server implementation

// library
interface PushNotification {
 // ...
}

interface PushNotificationOptions<T> {
  // ...
  onNotification?: (notification: PushNotification & T) => void;
  // ...
}

interface PushNotification {
  configure<T>(options: PushNotificationOptions<T>): void;
}

// end library

// unique implementation
export interface EMSPushNotification {
  // ...
}

const NotificationsHandler = () => {
  const notificationReceived = (notification: IPushNotification & EMSPushNotification): void => {
    // ...
  };

  useEffect(() => {
    PushNotification.configure<EMSPushNotification>({
      // ...
      onNotification: notificationReceived,
      // ...
    });
  }, []);

  return null;
};