Function onRegistered

onRegistered(
messaging: Messaging,
nextOrObserver: NextFn<string> | Observer<string>,
): Unsubscribe
Subscribes to Firebase Installation ID (FID) registration events.

Requires Installation ID messaging opt-in. While registered, a new subscriber receives the cached FID immediately; later events still fire.
Parameters
- messaging: Messaging
- nextOrObserver: NextFn<string> | Observer<string>
Returns Unsubscribe
- Defined in index.ts:797