前言

本节主要利用express搭配webpack作为开发服务器，并利用babel的插件，实现热替换功能，本节使用的包列表：

• express: node的服务器框架

• webpack-dev-middleware：webpack实时监控编译的中间件

• webpack-hot-middleware：hot替换中间件

• babel-plugin-react-transformbabel插件

• react-transform-hmr：react支持热替换

    npm install --save-dev webpack-dev-middleware
    npm install --save-dev webpack-hot-middleware
    npm install --save-dev babel-plugin-react-transform
    npm install --save-dev react-transform-hmr
  

添加的文件

关babel,node,server更详细的配置可以参考babel官方提供的方法example-node-server

• .babelrcnode启动时采用babel的编译配置
• scr/server.js服务器文件
• config/appConfig.js应用配置文件

新的目录结构

|-react-redux-example/
    ...
    |-config/
        |-appConfig.js
    |-src/
        |-app.js
        |-server.js
    ...
    |-.babelrc

更改配置

webpack.dev.js

react-transform可以直接写在.babelrc文件中的，但是我们以后会加入其他插件（加入后会与其他插件冲突）,所以这里写在webpack.dev.js中，新的配置如下：

var path = require('path')
var webpack = require('webpack')

var projectRootPath = path.resolve(__dirname,'..')

var config = {
  entry: [
    path.resolve(projectRootPath,'src/app.js')
  ],
  output:{
    path: path.resolve(projectRootPath,'public','assets'),
    filename: 'bundle.js',
    publicPath: '/assets/'
  },
  module:{
    loaders:[
      {
        test:/\.js$/,
        exclude:/node_modules/,
        loader:'babel-loader',
        query:{
          presets:['react','es2015'],
          plugins:[]
        }
      }
    ]
  },
  plugins:[
    new webpack.DefinePlugin({
      "process.env":{
        NODE_ENV:JSON.stringify(process.env.NODE_ENV)
      }
     })
  ]
}

//添加hotreplace支持
if (process.env.NODE_ENV !== 'production') {
  config.devtool = 'eval';
  config.entry.unshift ('webpack-hot-middleware/client')
  config.plugins.unshift(new webpack.HotModuleReplacementPlugin());

  // Note: enabling React Transform and React Transform HMR:
  config.module.loaders[0].query.plugins.push([
    'react-transform', {
      transforms: [{
        transform : 'react-transform-hmr',
        imports   : ['react'],
        locals    : ['module']
      }]
    }
  ]);
}

module.exports=config;

config/appConfig.js

应用基本的配置参数

const environment = {
  development: {
    isProduction: false
  },
  production: {
    isProduction: true
  }
}[process.env.NODE_ENV || 'development'];

module.exports = Object.assign({
  host: process.env.HOST || 'localhost',
  port: process.env.PORT||3000,
  apiHost: process.env.APIHOST || 'localhost',
  apiPort: process.env.APIPORT ||3030,
}, environment);

src/server.js

import path from 'path'
import webpack from 'webpack'
import express from 'express'
import appConfig from '../config/appConfig'

const app = express()

//webpack中间件配置，包括hotReplace
if(!appConfig.isProduction){
  const wpConfig = require('../config/webpack.dev.js');
  const compiler = webpack(wpConfig)

  const webpackMiddleware = require("webpack-dev-middleware");
  const webpackHotMiddleware =require('webpack-hot-middleware');

  app.use(webpackMiddleware(compiler,{
    publicPath:wpConfig.output.publicPath,
    noInfo:true,
    stats:{colors:true}
  }))
  app.use(webpackHotMiddleware(compiler))
}

//静态文件服务
app.use(express.static(path.join(__dirname,'../public')))

app.use('*',(req,res) =>{
  res.sendFile(path.join(__dirname,'../public/index.html'))
})

if (appConfig.port){
  app.listen(appConfig.port,appConfig.host,(err) =>{
    if (err){
      console.log(err)
    }else{
      console.info('server is running at %d',appConfig.port)
    }
  })
}else{
  console.error('No port is set')
}

src/app.js

热替换不能对根结点，所以这里写了一个简单的测试组件

import React from 'react'
import ReactDOM from 'react-dom'

class Hello extends React.Component {
  render(){
    return(
      <h1>Hello333</h1>
    )
  }
}

ReactDOM.render(<Hello />,document.getElementById('app'))

build

npm run dev

运行后打开浏览器访问http://localhost:3000,针对chrome浏览器打开“开发者工具console选项卡”看见如图效果后，说明热替换启用

NEXT

react路由设置及第一个组件编写