how to subscribe to firebase user update? code example

Example 1: update photoURL firebase

this.$fireAuth.currentUser.updateProfile({
    displayName: '',
    photoURL: '',
    email: ''
  })
  .then((r) => {
    console.log(r)
  })
  .catch((e) => {
  console.log(e)
})

Example 2: firebase auth update

In the newest version of firebase_auth:

FirebaseUser has been changed to User

AuthResult has been changed to UserCredential

GoogleAuthProvider.getCredential() has been changed to GoogleAuthProvider.credential()

onAuthStateChanged which notifies about changes to the user's sign-in state was replaced with authStateChanges()

currentUser() which is a method to retrieve the currently logged in user, was replaced with the property currentUser and it no longer returns a Future<FirebaseUser>