Google Sign-In for Websites and Angular 2 using Typescript

For your first problem solution is to use arrow function which will preserve context of this :

  onGoogleLoginSuccess = (loggedInUser) => {
    this.userAuthToken = loggedInUser.getAuthResponse().id_token;
    this.userDisplayName = loggedInUser.getBasicProfile().getName();
    console.log(this);
  }

Second issue is happening because third-party scripts run outside the context of Angular. Angular uses zones so when you run something, for example setTimeout(), which is monkey-patched to run in the zone, Angular will get notified. You would run jQuery in zone like this:

  constructor(private zone: NgZone) {
    this.zone.run(() => {
      $.proxy(this.onGoogleLoginSuccess, this);
    });
  }

There are many questions/answers about the zone with much better explanations then mine, if you want to know more, but it shouldn't be an issue for your example if you use arrow function.

I made a google-login component if you want an example.

  ngOnInit()
  {
    this.initAPI = new Promise(
        (resolve) => {
          window['onLoadGoogleAPI'] =
              () => {
                  resolve(window.gapi);
          };
          this.init();
        }
    )
  }

  init(){
    let meta = document.createElement('meta');
    meta.name = 'google-signin-client_id';
    meta.content = 'xxxxx-xxxxxx.apps.googleusercontent.com';
    document.getElementsByTagName('head')[0].appendChild(meta);
    let node = document.createElement('script');
    node.src = 'https://apis.google.com/js/platform.js?onload=onLoadGoogleAPI';
    node.type = 'text/javascript';
    document.getElementsByTagName('body')[0].appendChild(node);
  }

  ngAfterViewInit() {
    this.initAPI.then(
      (gapi) => {
        gapi.load('auth2', () =>
        {
          var auth2 = gapi.auth2.init({
            client_id: 'xxxxx-xxxxxx.apps.googleusercontent.com',
            cookiepolicy: 'single_host_origin',
            scope: 'profile email'
          });
          auth2.attachClickHandler(document.getElementById('googleSignInButton'), {},
              this.onSuccess,
              this.onFailure
          );
        });
      }
    )
  }

  onSuccess = (user) => {
      this._ngZone.run(
          () => {
              if(user.getAuthResponse().scope ) {
                  //Store the token in the db
                  this.socialService.googleLogIn(user.getAuthResponse().id_token)
              } else {
                this.loadingService.displayLoadingSpinner(false);
              }
          }
      );
  };

  onFailure = (error) => {
    this.loadingService.displayLoadingSpinner(false);
    this.messageService.setDisplayAlert("error", error);
    this._ngZone.run(() => {
        //display spinner
        this.loadingService.displayLoadingSpinner(false);
    });
  }

It's a bit late but I just want to give an example if someone want to use google login api with ng2.