how to check firebase auth for new user code example

Example 1: restrict the user from going to signup or login page if the user is already logged in firebase auth

var user = firebase.auth().currentUser;

if (user) {
  // User is signed in.
} else {
  // No user is signed in.
}

Example 2: update photoURL firebase

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