前端工程化开发的一个重要标志就是热替换技术，它大大的提高开发效率，使我们专注于写代码，webpack2中的热替换相比较1更加简洁。
1. 先看效果
Demo地址 https://github.com/leinov/react-hmr-demo
2.目录结构
3.项目目录结构文件描述
- bin 执行文件
- node_modules node包
-
public 静态资源文件
static 静态资源
dist 编译后文件 - src 项目js文件
- .bablrc babel配置文件
- webpack.config.dev.js开发模式webpack配置
-
webpack.config.pro.js生产模式webpack配置
3.技术依赖
- node
- react
- babel
- ES6/ES2015
- react-hmre
-
webpack
babel-loader,css-loader,sass-loader,style-loader,webpack-hot-middleware,webpack-hot-middleware
热加载最重要的几个配置是packge.json/devserver.js/webpack.config.dev.js/webpack.config.prod.js/.babelrc
packge.json
{@H_404_70@
"name"@H_404_70@:@H_404_70@ "react-hmr-demo"@H_404_70@,@H_404_70@
"version"@H_404_70@:@H_404_70@ "1.0.0"@H_404_70@,@H_404_70@
"description"@H_404_70@:@H_404_70@ "react-hmr-demo"@H_404_70@,@H_404_70@
"main"@H_404_70@:@H_404_70@ "index.js"@H_404_70@,@H_404_70@
"scripts"@H_404_70@:@H_404_70@ {@H_404_70@
"dev"@H_404_70@:@H_404_70@ "node bin/devserver.js"@H_404_70@,@H_404_70@
"build"@H_404_70@:@H_404_70@" webpack --config webpack.config.prod.js "@H_404_70@,@H_404_70@
"start"@H_404_70@:@H_404_70@"node bin/server.js"@H_404_70@
},@H_404_70@
"repository"@H_404_70@:@H_404_70@ {@H_404_70@
"type"@H_404_70@:@H_404_70@ "git"@H_404_70@,@H_404_70@
"url"@H_404_70@:@H_404_70@ "git+https://github.com/leinov/react-hmr-demo.git"@H_404_70@
},@H_404_70@
"author"@H_404_70@:@H_404_70@ "leinov"@H_404_70@,@H_404_70@
"license"@H_404_70@:@H_404_70@ "ISC"@H_404_70@,@H_404_70@
"dependencies"@H_404_70@:@H_404_70@ {@H_404_70@
"express"@H_404_70@:@H_404_70@ "^4.15.4"@H_404_70@,@H_404_70@
"react"@H_404_70@:@H_404_70@ "^15.6.1"@H_404_70@,@H_404_70@
"react-dom"@H_404_70@:@H_404_70@ "^15.6.1"@H_404_70@
},@H_404_70@
"devDependencies"@H_404_70@:@H_404_70@ {@H_404_70@
"babel-core"@H_404_70@:@H_404_70@ "^6.26.0"@H_404_70@,@H_404_70@
"babel-loader"@H_404_70@:@H_404_70@ "^7.1.2"@H_404_70@,@H_404_70@
"babel-polyfill"@H_404_70@:@H_404_70@ "^6.26.0"@H_404_70@,@H_404_70@
"babel-preset-es2015"@H_404_70@:@H_404_70@ "^6.24.1"@H_404_70@,@H_404_70@
"babel-preset-react"@H_404_70@:@H_404_70@ "^6.24.1"@H_404_70@,@H_404_70@
"babel-preset-react-hmre"@H_404_70@:@H_404_70@ "^1.1.1"@H_404_70@,@H_404_70@
"css-loader"@H_404_70@:@H_404_70@ "^0.28.5"@H_404_70@,@H_404_70@
"eventsource-polyfill"@H_404_70@:@H_404_70@ "^0.9.6"@H_404_70@,@H_404_70@
"node-sass"@H_404_70@:@H_404_70@ "^4.5.3"@H_404_70@,@H_404_70@
"sass-loader"@H_404_70@:@H_404_70@ "^6.0.6"@H_404_70@,@H_404_70@
"style-loader"@H_404_70@:@H_404_70@ "^0.18.2"@H_404_70@,@H_404_70@
"webpack"@H_404_70@:@H_404_70@ "^3.5.5"@H_404_70@,@H_404_70@
"webpack-dev-middleware"@H_404_70@:@H_404_70@ "^1.12.0"@H_404_70@,@H_404_70@
"webpack-hot-middleware"@H_404_70@:@H_404_70@ "^2.18.2"@H_404_70@
}@H_404_70@
}@H_404_70@
scripts的几个命令
$ npm run dev //开发模式
$ npm run build //编译打包
npm start //正式环境运行
webpack.config.dev.js
var@H_404_70@ path =@H_404_70@ require@H_404_70@('path'@H_404_70@);@H_404_70@
var@H_404_70@ webpack =@H_404_70@ require@H_404_70@('webpack'@H_404_70@);@H_404_70@
module@H_404_70@.exports@H_404_70@ =@H_404_70@ {@H_404_70@
devtool@H_404_70@:@H_404_70@ 'cheap-module-eval-source-map'@H_404_70@,@H_404_70@//打包构建信息@H_404_70@
entry@H_404_70@:@H_404_70@ [
'eventsource-polyfill'@H_404_70@,@H_404_70@//for IE@H_404_70@
'webpack-hot-middleware/client'@H_404_70@,@H_404_70@//webpack服务连接到浏览器接收更新@H_404_70@
'./src/index.js'@H_404_70@
],@H_404_70@
output@H_404_70@:@H_404_70@ {@H_404_70@
filename@H_404_70@:@H_404_70@ 'boundle.js'@H_404_70@,@H_404_70@
publicPath@H_404_70@:@H_404_70@ '/dist/js/'@H_404_70@
},@H_404_70@
module@H_404_70@:@H_404_70@ {@H_404_70@
loaders@H_404_70@:@H_404_70@ [{@H_404_70@
test@H_404_70@:@H_404_70@ /@H_404_70@\.@H_404_70@js@H_404_70@$@H_404_70@/@H_404_70@,@H_404_70@
loaders@H_404_70@:@H_404_70@ ['babel-loader'@H_404_70@],@H_404_70@
exclude@H_404_70@:@H_404_70@ /node_modules/@H_404_70@ //哪些文件下的需要用到babel@H_404_70@
},@H_404_70@ {@H_404_70@
test@H_404_70@:@H_404_70@ /@H_404_70@\.@H_404_70@css@H_404_70@$@H_404_70@/@H_404_70@,@H_404_70@
loaders@H_404_70@:@H_404_70@ ['style-loader'@H_404_70@,@H_404_70@ 'css-loader'@H_404_70@],@H_404_70@
},@H_404_70@
{@H_404_70@
test@H_404_70@:@H_404_70@ /@H_404_70@\.@H_404_70@scss@H_404_70@$@H_404_70@/@H_404_70@,@H_404_70@ 'css-loader'@H_404_70@,@H_404_70@ 'sass-loader'@H_404_70@],@H_404_70@
{@H_404_70@
test@H_404_70@:@H_404_70@ /@H_404_70@\.(@H_404_70@png@H_404_70@|@H_404_70@jpg@H_404_70@|@H_404_70@gif@H_404_70@)$@H_404_70@/@H_404_70@,@H_404_70@
loaders@H_404_70@:@H_404_70@ ['url?limit=8192&name=images/[name].[ext]'@H_404_70@],@H_404_70@
}@H_404_70@
]
}@H_404_70@ ,@H_404_70@
resolve@H_404_70@:{@H_404_70@
alias@H_404_70@:@H_404_70@ {@H_404_70@
css@H_404_70@:@H_404_70@ path@H_404_70@.resolve@H_404_70@(__dirname,@H_404_70@ 'public/static/css/'@H_404_70@),@H_404_70@ //css目录别名@H_404_70@
}@H_404_70@
},@H_404_70@
plugins@H_404_70@:@H_404_70@ [
new@H_404_70@ webpack@H_404_70@.HotModuleReplacementPlugin@H_404_70@(),@H_404_70@//热替换插件@H_404_70@
new@H_404_70@ webpack@H_404_70@.NoEmitOnErrorsPlugin@H_404_70@()
]
};@H_404_70@
.babelrc
{
"presets": ["react","es2015"]，
"env": {
"development": {
"presets": ["react-hmre"]
}
}
}
devserver.js
var path = require('path');
var express = require('express');
var webpack = require('webpack');
var config = require('../webpack.config.dev');
var app = express();
var compiler = webpack(config);
var webpackDevMiddleware = require("webpack-dev-middleware");
app.use(webpackDevMiddleware(compiler,{
noInfo: false,//true将打印编译信息（建议false，true会打印很多信息）
publicPath: config.output.publicPath //绑定middleware
}));
var webpackHotMiddleware = require('webpack-hot-middleware');
app.use(webpackHotMiddleware(compiler));
app.get('*',function(req,res) {
res.sendFile(path.resolve(__dirname,'../index.html')); //
});
app.listen(3100,function(err) {
if (err) {
console.log(err);
return;
}
console.log('Listening at http://localhost:3100');
});
这样就可以实现热加载了，在项目根目录执行
$ npm run dev
webpack.config.prod.js
var path = require('path');
var webpack = require('webpack');
module.exports = {
devtool: 'cheap-module-eval-source-map',entry: [
'./src/index.js'
],output: {
path: path.join(__dirname,'public/dist/js'),filename: 'boundle.js',},module: {
loaders: [{
test: /\.js$/,loaders: ['babel-loader'],exclude: /node_modules/
},{
test: /\.css$/,loaders: ['style-loader','css-loader'],{
test: /\.scss$/,'css-loader','sass-loader'],{
test: /\.(png|jpg|gif)$/,loaders: ['url?limit=8192&name=images/[name].[ext]'],}
]
},resolve:{
alias: {
css: path.resolve(__dirname,'public/static/css/'),img: path.resolve(__dirname,'public/static/img/'),}
},plugins: [
new webpack.HotModuleReplacementPlugin(),new webpack.NoEmitOnErrorsPlugin(),new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false
}
})
]
};
生产的webpack主要完成开发后的编译打包，在plugins里多了压缩插件,在项目根目录执行
$ npm run build
bin/server.js
生产环境启动文件
var path = require('path');
var express = require('express');
var app = express();
var oneYear = 60 * 1000 * 60 * 24 * 30;
app.use(express.static(path.resolve(__dirname,'../public'),{ maxAge: oneYear }));
app.get('*','../index.html'));
});
app.listen(3200,function(err) {
if (err) {
console.log(err);
return;
}
console.log('Listening at http://localhost:3200');
});
$ npm start //运行生产环境
Demo地址 https://github.com/leinov/react-hmr-demo
