angular2-keycloak-integation(V5).js

  // Login.Component.ts
  
  // check if user is already logged in
  ngOnInit() {
    this.checkLoginSubscriber = this.loginService.isLoggedIn()
      .subscribe(loggedIn => {
        //console.log("Logged In?: " + loggedIn);
        if (loggedIn) {
          this.loginService.redirectToAuthorizedPage();
        }
      });
  }

  // do on demand login when the login button is clicked for example.
  doLogin() {
    this.loginSubscriber = this.loginService.login().subscribe(loggedIn => {
      //console.log("logged IN ");
      if (loggedIn)
        this.router.navigate(['/test']);
    });
  }

// Login.Service.ts

  private keycloakAuth: any;

  constructor(private router: Router) {
    this.keycloakAuth = new Keycloak('../keycloak.json');
  }

  // on demand login 
  login(): Observable<boolean> {
    this.auth = null;
    return Observable.create(obserer => {
      this.keycloakAuth.init({ onLoad: 'login-required' })
        .success(() => {
          if (this.keycloakAuth.authenticated) {
            //console.log('login success');
            this.createAuth(); // the auth object as mentioned in the keycloak angular 2 example
            obserer.next(true);
          }
            obserer.next(false);
        });
    });
  }
  
  // login check if previously logged in or after a reply from keycloak
  isLoggedIn(): Observable<boolean> {
  return Observable.create(observer => {
    if (this.auth) { // store this object to prevent multiple keycloak calls
      observer.next(this.auth.loggedIn);
      observer.complete();
    } else {
      this.keycloakAuth.isLoggedIn().success((isLoggedIn: boolean) => {
        if (isLoggedIn) {
          this.keycloakAuth.watchLogin();
          if (!this.auth)
            this.createAuth();
          observer.next(true);
        } else {
          observer.next(false);
        }
        observer.complete();
      });
    }
  });
  }