How to implement SignIn with Google in Angular 2 using Typescript

Question

I have been trying to implement sign in with Google in angular 2 in a separate login component. I am unable to implement it with the documentation available in Google https:

Answer 1

Lexical scoping with an arrow (=>) function makes the use of let that = this; unnecessary.

A cleaner version of Pravesh's example, without the need for the that scoping work-around, would be:

Index.html

<script src="https://apis.google.com/js/platform.js" async defer></script>

Component.ts

declare const gapi: any;

@Component({
  selector: 'google-signin',
  template: '<button id="googleBtn">Google Sign-In</button>'
})
export class GoogleSigninComponent implements AfterViewInit {

  private clientId:string = 'YOUR_CLIENT_ID.apps.googleusercontent.com';

  private scope = [
    'profile',
    'email',
    'https://www.googleapis.com/auth/plus.me',
    'https://www.googleapis.com/auth/contacts.readonly',
    'https://www.googleapis.com/auth/admin.directory.user.readonly'
  ].join(' ');

  public auth2: any;

  public googleInit() {        
    gapi.load('auth2', () => {
      this.auth2 = gapi.auth2.init({
        client_id: this.clientId,
        cookiepolicy: 'single_host_origin',
        scope: this.scope
      });
      this.attachSignin(this.element.nativeElement.firstChild);
    });
  }

  public attachSignin(element) {
    this.auth2.attachClickHandler(element, {},
      (googleUser) => {
        let profile = googleUser.getBasicProfile();
        console.log('Token || ' + googleUser.getAuthResponse().id_token);
        console.log('ID: ' + profile.getId());
        // ...
      }, function (error) {
        console.log(JSON.stringify(error, undefined, 2));
      });
  }

  constructor(private element: ElementRef) {
    console.log('ElementRef: ', this.element);
  }

  ngAfterViewInit() {
    this.googleInit();
  }
}

Template

<div id="googleBtn">Google</div>

Working Plnkr