class request {
 constructor() {
  this._baseUrl = 'https://xxx.com/api';
  this._token = wx.getStorageSync('token');
  this._header = {'Authorization': 'Bearer ' + token}
 }

 /**
  * GET类型的网络请求
  */
 getRequest(url, data, header = this._header) {
  return this.requestAll(url, data, header, 'GET')
 }

 /**
  * DELETE类型的网络请求
  */
 deleteRequest(url, data, header = this._header) {
  return this.requestAll(url, data, header, 'DELETE')
 }

 /**
  * PUT类型的网络请求
  */
 putRequest(url, data, header = this._header) {
  return this.requestAll(url, data, header, 'PUT')
 }

 /**
  * POST类型的网络请求
  */
 postRequest(url, data, header = this._header) {
  return this.requestAll(url, data, header, 'POST')
 }

 /**
  * 网络请求
  */
 requestAll(url, data, header, method) {
  return new Promise((resolve, reject) => {
   wx.request({
    url: this._baseUrl + url,
    data: data,
    header: header,
    method: method,
    success: (res => {
     if (res.statusCode === 200) {
      //200: 服务端业务处理正常结束
      resolve(res)
     } else {
      //其它错误，提示用户错误信息
      reject(res)
     }
    }),
    fail: (res => {
     reject(res)
    })
   })
  })
 }
}

export default request

import request from './request.js'
App({
 myRequest(){
  return new request();
 }
})

const app = getApp();//新建页面时 默认引入
const ajax = app.myRequest();//初始化一个的request() 实例

Page({
 data:{},
 onLoad(){
  this.getData(); 
 },
 getData(){
  ajax.getRequest('/getList',{id: 1024}).then((res)=>{
   console.log(res);
  }).catch((err)=>{
   console.log(err);
  })
 }
})