Angular 4 firebase .currentUser.getToken ()

Как решить эту проблему?

firebase.User.prototype.getToken is deprecated.
Please use firebase.User.prototype.getIdToken instead.

Вот мой код:

signinUser(email: string, password: string) {
  firebase.auth().signInWithEmailAndPassword(email, password)
  .then(
     response => {
        firebase.auth().currentUser.getToken()
           .then(
              (token: string) => this.token = token
           )
     }
  )
  .catch(
     error => console.info(error)
  );
}