What Value Does Firebase Auth Identifier Store From Facebook Login If User Is Not Registered With Email

What value does Firebase Auth Identifier store from Facebook Login If user is not registered with email but with Phone Number. My app provides facebook login but now when a user is

Solution 1:

Firebase Auth backend will use the corresponding Facebook ID to identify that user. You can get the Facebook ID from the providerData list in the currentUser. There will be an entry whose uid is the Facebook ID. So there is no null identifier. Only the email is null.

You can also use updateEmail API if you want to set the email yourself on that user.