let API_HOST = "http://xxx.com/xxx";
let DEBUG = true;//切换数据入口
var Mock = require('mock.js')
function ajax(data = '', fn, method = "get", header = {}) {
  if (!DEBUG) {
    wx.request({
      url: config.API_HOST + data,
      method: method "Content-Type": "application/json" },
      success: function (res) {
        fn(res);
      }
    });
  } else {
    // 模拟数据
    var res = Mock.mock({
      'error_code': '',
      'error_msg': '',
      'data|10': [{
        'id|+1': 1,
        'img': "@image('200x100', '#4A7BF7','#fff','pic')",
        'title': '@ctitle(3,8)',
        'city': "@county(true)",
        'stock_num': '@integer(0,100)',//库存数量 
        'marketing_start': '@datetime()',
        'marketing_stop': '@now()',
        'price': '@integer(100,2000)',//现价，单位：分 
        'original_price': '@integer(100,3000)'
      }] 
    })
    // 输出结果
    // console.log(JSON.stringify(res, null, 2))
    fn(res);
  }
}
module.exports = {
  ajax: ajax
}

//index.js
//获取应用实例
var app = getApp()
var API = require('../../utils/api.js')
Page({
  data: {
  },
  onLoad: function () {
    console.log('onLoad')
    var that = this
    // 使用 Mock
    API.ajax('', function (res) {
      //这里既可以获取模拟的res
      console.log(res)
      that.setData({
        list:res.data
      })
    });

    console.log(this.data.list)
  }
})

<!--index.wxml-->
<block wx:for="{{list}}" wx:key="name">
 <view>{{item.title}}</view>
 <text>{{item.city}}</text>
 <view>
  <text>{{item.marketing_start}}</text>
 </view>
 <image src='{{item.img}}'></image>
</block>