angular 使用jwt token验证

/**
 * Created by 何欣澄 on 2017/5/28 0028.
 */
import {Observable} from 'rxjs/Observable';
import {Injectable} from '@angular/core';
import {
  Http,
  RequestOptionsArgs,
  RequestOptions,
  Response,
  Headers
} from '@angular/http';

const mergeToken = (options: RequestOptionsArgs = {}) => { ①
  const newOptions = new RequestOptions({}).merge(options);
  const newHeaders = new Headers(newOptions.headers);
  const jwt = localStorage.getItem(