高仿饿了么mock本地数据

新版webpack.dev.conf.js配置本地数据访问：
// 引入express 模块
const express = require(‘express‘)
// 创建express对象
const app = express()
// 引入请求文件 加载本地数据文件
const appData = require(‘../data.json‘)
// 获取对应的本地数据
const seller = appData.seller
const goods = appData.goods 
const ratings = appData.ratings

devServer: {
    clientLogLevel: ‘warning‘,
    historyApiFallback: {
      rewrites: [
        { from: /.*/, to: path.posix.join(config.dev.assetsPublicPath, ‘index.html‘) },
      ],
    },
    
    hot: true,
    contentBase: false, // since we use CopyWebpackPlugin.
    compress: true,
    host: HOST || config.dev.host,
    port: PORT || config.dev.port,
    open: config.dev.autoOpenBrowser,
    overlay: config.dev.errorOverlay
      ? { warnings: false, errors: true }
      : false,
    publicPath: config.dev.assetsPublicPath,
    proxy: config.dev.proxyTable,
    quiet: true, // necessary for FriendlyErrorsPlugin
    watchOptions: {
      poll: config.dev.poll,
    },
    before (app) {
      // 创建不同的路由对象  配置接口
      app.get(‘/api/seller‘, (req, res) => {
        res.json({
          errno: 0,
          data: seller //接口返回json数据，上面配置的数据seller就赋值给data请求后调用
       })
      })
      app.get(‘/api/goods‘, (req, res) => {
        res.json({
          errno: 0,
          data: goods
        })
      })
      app.get(‘/api/ratings‘, (req, res) => {
        res.json({
          errno: 0,
          data: ratings
        })
      })
    }
  },