Holds the user metadata for the current
const user = firebase.auth().currentUser; console.log('User metadata: ', user.metadata);
Returns the timestamp at which this account was created as dictated by the server clock as an ISO Date string.
creationTime: undefined | string;
Returns the last signin timestamp as dictated by the server clock as an ISO Date string. This is only accurate up to a granularity of 2 minutes for consecutive sign-in attempts.
lastSignInTime: undefined | string;