Firebase Auth Is there a way to make sure displayName is unique between all users?

Question

I created a function to create a new user with the following code, which creates the user and changes their displayName:

export function handleSignup(email, password, name) {
    firebase_auth.createUserWithEmailAndPassword(email, password)
    .then(function(reponse) {
        reponse.user.updateProfile({displayName: username});
    })
    .catch(function(error) {
        // Handle error
    });
}

The problem is that anyone can make the same username, it doesn't check for uniqueness. Is there a way for me to request a user by displayName and see if it already exists before attempting to create the new user?

Answer 1

Firebase Authentication doesn't enforce uniqueness of any of its user properties. Only the assigned UID is guaranteed to be unique among all users in a project.

If you need to implement unique user names, you will have to use something else to help you with that, such as a database, and link that data to the user account using the user's UID.