Catching Rejections

import { HttpClient } from '@angular/http/common';
import { Injectable } from '@angular/core';
​
@Injectable()
export class AuthService {
​
  constructor(private http: HttpClient) {}
​
  login(username, password) {
    const payload = {
      username: username,
      password: password
    };
​
    this.http.post(`${ BASE_URL }/auth/login`, payload)
      .map(response => response.json())
      .subscribe(
        authData => this.storeToken(authData.id_token),
        (err) => console.error(err),
        () => console.log('Authentication Complete')
      );
  }
}