webpackDevMiddleware

const express = require('express')
const webpackDevMiddleware = require('webpack-dev-middleware')
const webpack = require('webpack')
const app = express()
// 获取配置文件
const config = require('./webpack.config.js')
const compiler = webpack(config)
app.use(webpackDevMiddleware(compiler))
// 开启端口上的服务
app.listen(3000, () => {
  console.log('服务运行在 3000端口上')
})