How to detect whether google auth login user is a NewUser or not using firebase in react native

Question

How to detect the login user is an existing user or a new user using firebase in react native. I have used Google auth to create the authentication but unfortunately I am not getting any field called isNewUser in return promise.

below is my code...

async function onGoogleButtonPress() {
    // Get the users ID token
    const {idToken} = await GoogleSignin.signIn();

    // Create a Google credential with the token
    const googleCredential = auth.GoogleAuthProvider.credential(idToken);

    // Sign-in the user with the credential
    return auth().signInWithCredential(googleCredential);
  }

  function onAuthStateChanged(user) {
    if (user) {
      firestore()
        .collection('Users')
        .doc(user.uid)
        .set({
          user: user.displayName,
        email: user.email,
        photo: user.photoURL,
        })
        .then(() => {
          console.log('User added!');
        });
    }
    if (initializing) setInitializing(false);
  }


 useEffect(() => {
    const subscriber = auth().onAuthStateChanged(onAuthStateChanged);
    return subscriber; // unsubscribe on unmount
  });

This is the return response I am getting.

 {"displayName": "***", "email": "**@gmail.com", "emailVerified": true, "isAnonymous": false, "metadata": {"creationTime": 15960**412290, "lastSignInTime": 15960**65185}, "phoneNumber": null, "photoURL": "**", "providerData": [[Object]], "providerId": "firebase", "uid": "*******"}

My problem now is everytime once user successfully authenticate google signin method its adding data's to the firebase data base. Does there any way that I can detect the user is a new user or a existing user??

A help will be great and appreciable :)

Answer 1

The isNewUser property is in the UserCredential object, which is only available right after the call to signInWithCredential.

const credentialPromise = auth().signInWithCredential(googleCredential);
credentialPromise.then((credential) => {
  console.log(credential.additionalUserInfo.isNewUser);
})

---

You can determine whether the user is new from the auth state listener, by comparing the user's creation timestamp to their last sign in:

function onAuthStateChanged(user) {
  if (user) {
    if (user.metadata.creationTime <> user.metadata.lastSignInTime) {
      ...
    }
  }
}

---

Also see:

• the documentation for AdditionalUserInfo.
• the documentation for UserMetadata.