How do I detect if a user is already logged in Firebase?

Question

I\'m using the firebase node api in my javascript files for Google login.

firebase.initializeApp(config);
let provider = new firebase.auth.GoogleAuthProvide         


        

Answer 1

https://firebase.google.com/docs/auth/web/manage-users

You have to add an auth state change observer.

firebase.auth().onAuthStateChanged(function(user) {
  if (user) {
    // User is signed in.
  } else {
    // No user is signed in.
  }
});