"Sign In With Google" Problem

Hi! im new on ionic and im learning about “Sign in With Google” from this link :

And im pretty confused with this example code from that link :

import { Component } from '@angular/core';
import { Auth, User } from '@ionic/cloud-angular';

@Component( ... )
export class LoginPage {
  constructor(public auth: Auth, public user: User) {
    ...
  }
}

and

this.auth.login('google').then( ... );

What does the ... mean?

Don’t invest any time in Ionic Auth. It is deprecated and will go away soon. See here: https://docs.ionic.io/services/auth/

Ionic Auth has been deprecated. As of January 31, 2018, we will no longer provide the Ionic Auth user authentication service.

thankyou!! it would be a waste of time if u not informing me about that…
so, what method should i use?

Please open a new topic about that. Thanks.