Function onJoin

onJoin(fn): Unsubscribe
Subscribe to users joining the room.
Parameters
- fn: ((user) => void)
  
  Handler that receives the user who joined.
  - - (user): void
    - Parameters
      
      user: RemoteUser
      
      Returns void
Returns Unsubscribe
A function that cancels the subscription. Call it on teardown.
- Defined in packages/core/subpaths/users/index.ts:51