Using Session Storage to navigate to the initial page after login into Azure AD

authentication-guard.ts

import { Injectable } from '@angular/core';
import { Router, CanActivate, CanActivateChild, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { AdalService } from 'adal-angular4';

@Injectable()
export class AuthenticationGuard implements CanActivate, CanActivateChild {
  constructor(
    private router: Router,
    private adal: AdalService
  ) { }

  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): boolean {
    if (this.adal.userInfo.authenticated) {
      return true;
    }
    else {
      this.router.navigate(['/login'], { queryParams: { returnUrl: state.url } });
      return false;
    }
  }

  canActivateChild(childRoute: ActivatedRouteSnapshot, state: RouterStateSnapshot): boolean {
    return this.canActivate(childRoute, state);
  }
}

login.component.html

<p>
  Click on the following button if login window doesn't show automatically beacuse
  the browser blocked the popup.
</p>
<button (click)="login()">Login Azure Active Directory</button>
<p>
  If you want the popup to show up automatically, please enable popups on this site. 
</p>

login.component.ts

import { Component, OnInit } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';
import { AdalService } from 'adal-angular4';
import { environment } from '../../../environments/environment';


@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css']
})
export class LoginComponent implements OnInit {

  constructor(private route: ActivatedRoute, private router: Router, private adal: AdalService) {
  }

  login() {
    var context: any = this.adal["context"];
    this.adal.login();
    this.checkLogin();
  }

  checkLogin() {
    const returnUrl = this.route.snapshot.queryParams['returnUrl'] || sessionStorage.returnUrl || '/';
    var context: any = this.adal["context"];
    var intervalHandle = window.setInterval(() => {
      if (context._user) {
        this.adal.refreshDataFromCache();
        this.adal.acquireToken(context.config.loginResource).subscribe(token => {
          clearTimeout(intervalHandle);
          this.adal.userInfo.authenticated = true;
          this.adal.userInfo.token = token;
          this.router.navigate([returnUrl]);
        }, error => {
            console.error("Failed to acquire token for resource ", context.config.loginResource, error);
          });

        this.adal.acquireToken(this.adal.getResourceForEndpoint(environment.apiUrl)).subscribe(token => {
         
        }, error => {
          console.error("Failed to acquire token for resource ", context.config.loginResource, error);
        });
      }
    }, 500);
  }

  ngOnInit() {
    console.log("returnUrl %s", sessionStorage.returnUrl);
    const returnUrl = this.route.snapshot.queryParams['returnUrl'] || sessionStorage.returnUrl || '/';
    if (this.adal.userInfo.authenticated) {
      this.router.navigate([returnUrl]);
    }
    else {
      sessionStorage.returnUrl = returnUrl;
      this.login();
    }
  }
}