需求：在请求头中添加token，网上借鉴了几份代码，没有成功，以下是实践出来的，记录下代码

Vue.http.interceptors.push(function (request, next) {
  // modify url  本地调试使用本地ip地址
  const url = '';
  request.url = `${url}${request.url}`;
  // modify headers
  if (store.getters.getToken) {
      request.headers.set('token', `${store.getters.getToken}`);
  }
  // request.headers.set('X-CSRF-TOKEN', 'TOKEN');
  next((response) => {
    // 请求发送后的处理逻辑
    if (response.status === 400 || response.status === 401) {
      // 当 Token 已经失效时，清空所有保存在 setToken 的数据
    }
    return response;
  });
});

注意：在添加token是，是需要后台进行允许的，Access-Control-Allow-Headers:token

Access-Control-Allow-Headers:Accept,Pragma,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,token
Access-Control-Allow-Methods:GET, POST, DELETE, PUT,OPTIONS
Access-Control-Allow-Origin:*
Access-Control-Max-Age:3600
Allow:GET, HEAD, POST, PUT, DELETE, OPTIONS, PATCH
Date:Thu, 15 Jun 2017 13:19:16 GMT
Transfer-Encoding:chunked

如果没有允许则会报一下错误，你没有权限
Request header field token is not allowed by Access-Control-Allow-Headers in preflight response.

参考地址
https://github.com/pagekit/vue-resource/blob/master/docs/http.md#options