Function onMessage

onMessage(
messaging: Messaging,
listener: (message: RemoteMessage) => any,
): () => void
When any FCM payload is received, the listener callback is called with a RemoteMessage.

This subscriber method is only called when the app is active (in the foreground).
Parameters
- messaging: Messaging
  Messaging instance.
- listener: (message: RemoteMessage) => any
  Called with a RemoteMessage when a new FCM payload is received from the server.
Returns () => void
Function to unsubscribe from the message listener.
- Defined in modular.ts:81