详解vue-cli脚手架中webpack配置方法

什么是webpack

webpack是一个module bundler（模块打包工具），所谓的模块就是在平时的前端开发中，用到一些静态资源，如JavaScript、CSS、图片等文件，webpack就将这些静态资源文件称之为模块

webpack支持AMD和CommonJS，以及其他的一些模块系统，并且兼容多种JS书写规范，可以处理模块间的以来关系，所以具有更强大的JS模块化的功能，它能对静态资源进行统一的管理以及打包发布，在官网中用这张图片介绍：

它在很多地方都能替代Grunt和Gulp，因为它能够编译打包CSS，做CSS预处理，对JS的方言进行编译，打包图片，代码压缩等等。所以在我接触了webpack之后，就不太想用gulp了

为什么使用webpack

总结如下：

webpack主要是用于vue和React较多，其实它就非常像Browserify，但是将应用打包为多个文件。如果单页面应用有多个页面，那么用户只从下载对应页面的代码. 当他么访问到另一个页面, 他们不需要重新下载通用的代码。

基于本人项目使用

vue webpack的配置文件的基本目录结构如下：

config
├── dev.env.js //dev环境变量配置
├── index.js // dev和prod环境的一些基本配置
└── prod.env.js // prod环境变量配置
build
├── build.js // npm run build所执行的脚本
├── check-versions.js // 检查npm和node的版本
├── logo.png
├── utils.js // 一些工具方法，主要用于生成cssLoader和styleLoader配置
├── vue-loader.conf.js // vueloader的配置信息
├── webpack.base.conf.js // dev和prod的公共配置
├── webpack.dev.conf.js // dev环境的配置
└── webpack.prod.conf.js // prod环境的配置

Config文件夹下文件详解

dev.env.js

config内的文件其实是服务于build的，大部分是定义一个变量export出去

use strict //[采用严格模式]
/**
* [webpack-merge提供了一个合并函数，它将数组和合并对象创建一个新对象
] 
*/
const merge = require('webpack-merge')
const prodEnv = require('./prod.env')

module.exports = merge(prodEnv, {
 NODE_ENV: '"development"'
})

prod.env.js

当开发时调取dev.env.js的开发环境配置，发布时调用prod.env.js的生产环境配置

use strict
module.exports = {
NODE_ENV: '"production"'
}

index.js

const path = require('path')
module.exports = {
 /**
 * [开发环境配置]
 */
dev: {
 assetsSubDirectory: 'static', // [子目录,一般存放css,js,image等文件]
assetsPublicPath: '/', // [根目录]
/**
* [配置服务代理] 
*/
 proxyTable: {
 '/hcm': {
 target: 'https://127.0.0.1:8448',
 changeOrigin: true,
 secure: false
 },
 headers: {
 "Access-Control-Allow-Origin": "*",
 "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
 "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
 }
 },
 host: '127.0.0.1', // [浏览器访问地址]
 port: 8083, // [端口号设置，端口号占用出现问题可在此处修改]
 autoOpenBrowser: true, // [是否在编译（输入命令行npm run dev）后打开http://127.0.0.1:8083/页面]
 errorOverlay: true, // [浏览器错误提示]
 notifyOnErrors: true, // [跨平台错误提示]
 poll:false, // [使用文件系统(file system)获取文件改动的通知devServer.watchOptions] 
 useEslint: true, // [是否启用代码规范检查]
 showEslintErrorsInOverlay: false, // [是否展示eslint的错误提示]
 devtool: 'eval-source-map', // [增加调试，该属性为原始源代码]
 cacheBusting: true, // [使缓存失效]
 cssSourceMap: false // [代码压缩后进行调bug定位将非常困难，于是引入sourcemap记录压缩前后的位置信息记录，当产生错误时直接定位到未压缩前的位置，将大大的方便我们调试]
 },
/**
* [生产环境配置] 
*/
 build: {
 /**
* [index、login、license、forbidden、notfound、Internal.licenses编译后生成的位置和名字，根据需要改变后缀] 
*/
 index: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/index.html'),
 login: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/login.html'),
 license: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/license.html'),
 forbidden: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/error/403.html'),
 notfound: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/error/404.html'),
 internal: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/error/500.html'),
 licenses: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources/docs/licenses.html'),
/**
* [编译后存放生成环境代码的位置] 
*/
 assetsRoot: path.resolve(__dirname, '../../hcm-modules/hcm-web/src/main/resources/META-INF/resources'),
 assetsSubDirectory: 'static', //js、css、images存放文件夹名
 assetsPublicPath: './', //发布的根目录，通常本地打包dist后打开文件会报错，此处修改为./。如果是上线的文件，可根据文件存放位置进行更改路径
 productionSourceMap: true,
 devtool: '#source-map',
 productionGzip: false, //unit的gzip命令用来压缩文件，gzip模式下需要压缩的文件的扩展名有js和css
 productionGzipExtensions: ['js', 'css'],
 bundleAnalyzerReport: process.env.npm_config_report //打包分析
 }
}

build文件夹下文件详解

build.js

该文件作用，即构建生产版本。package.json中的scripts的build就是node build/build.js，输入命令行npm run build对该文件进行编译生成生产环境的代码。

require('./check-versions')() //check-versions：调用检查版本的文件。加（）代表直接调用该函数
process.env.NODE_ENV = 'production' //设置当前是生产环境
/**
*下面定义常量引入插件
*/
const ora = require('ora') //加载动画
const rm = require('rimraf') //删除文件
const path = require('path')
const chalk = require('chalk') //对文案

check-versions.js

该文件用于检测node和npm的版本，实现版本依赖

const chalk = require('chalk') 
const semver = require('semver') //对版本进行检查
const packageConfig = require('../package.json')
const shell = require('shelljs')
function exec (cmd) {
 //返回通过child_process模块的新建子进程，执行 Unix 系统命令后转成没有空格的字符串
 return require('child_process').execSync(cmd).toString().trim()
}
const versionRequirements = [
 {
 name: 'node',
 currentVersion: semver.clean(process.version), //使用semver格式化版本
 versionRequirement: packageConfig.engines.node //获取package.json中设置的node版本
 }
]
if (shell.which('npm')) {
 versionRequirements.push({
 name: 'npm',
 currentVersion: exec('npm --version'), // 自动调用npm --version命令，并且把参数返回给exec函数，从而获取纯净的版本号
 versionRequirement: packageConfig.engines.npm
 })
}
module.exports = function () {
 const warnings = []
 for (let i = 0; i < versionRequirements.length; i++) {
 const mod = versionRequirements[i]
 if (!semver.satisfies(mod.currentVersion, mod.versionRequirement)) {
 //上面这个判断就是如果版本号不符合package.json文件中指定的版本号，就执行下面错误提示的代码
warnings.push(mod.name + ': ' +
 chalk.red(mod.currentVersion) + ' should be ' +
 chalk.green(mod.versionRequirement)
 )
 }
 }
 if (warnings.length) {
 console.log('')
 console.log(chalk.yellow('To use this template, you must update following to modules:'))
 console.log()
 for (let i = 0; i < warnings.length; i++) {
 const warning = warnings[i]
 console.log(' ' + warning)
 }
 console.log()
 process.exit(1)
 }
}

utils.js

utils是工具的意思，是一个用来处理css的文件。

const path = require('path')
const config = require('../config')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const packageConfig = require('../package.json')
exports.assetsPath = function (_path) {
 const assetsSubDirectory = process.env.NODE_ENV === 'production'
 ? config.build.assetsSubDirectory
 : config.dev.assetsSubDirectory
 return path.posix.join(assetsSubDirectory, _path)
}
exports.cssLoaders = function (options) {
 options = options || {}
//使用了css-loader和postcssLoader，通过options.usePostCSS属性来判断是否使用postcssLoader中压缩等方法

 const cssLoader = {
 loader: 'css-loader',
 options: {
 sourceMap: options.sourceMap
 }
 }
 const postcssLoader = {
 loader: 'postcss-loader',
 options: {
 sourceMap: options.sourceMap
 }
 }
 // generate loader string to be used with extract text plugin
 function generateLoaders (loader, loaderOptions) {
 const loaders = options.usePostCSS ? [cssLoader, postcssLoader] : [cssLoader]
 if (loader) {
 loaders.push({
 loader: loader + '-loader',
 //Object.assign是es6语法的浅复制，后两者合并后复制完成赋值
 options: Object.assign({}, loaderOptions, {
 sourceMap: options.sourceMap
 })
 })
 }
 // Extract CSS when that option is specified
 // (which is the case during production build)
if (options.extract) {
//ExtractTextPlugin可提取出文本，代表首先使用上面处理的loaders，当未能正确引入时使用vue-style-loader
 return ExtractTextPlugin.extract({
 use: loaders,
 fallback: 'vue-style-loader',
 publicPath: '../../'
 })
} else {
//返回vue-style-loader连接loaders的最终值
 return ['vue-style-loader'].concat(loaders)
 }
 }
 // https://vue-loader.vuejs.org/en/configurations/extract-css.html
 return {
 css: generateLoaders(),//需要css-loader 和 vue-style-loader
 postcss: generateLoaders(),//需要css-loader和postcssLoader 和 vue-style-loader
 less: generateLoaders('less'), //需要less-loader 和 vue-style-loader
 sass: generateLoaders('sass', { indentedSyntax: true }), //需要sass-loader 和 vue-style-loader
 scss: generateLoaders('sass'), //需要sass-loader 和 vue-style-loader
 stylus: generateLoaders('stylus'), //需要stylus-loader 和 vue-style-loader
 styl: generateLoaders('stylus') //需要stylus-loader 和 vue-style-loader
 }
}
// Generate loaders for standalone style files (outside of .vue)
exports.styleLoaders = function (options) {
 const output = []
 const loaders = exports.cssLoaders(options)
//将各种css,less,sass等综合在一起得出结果

vue-loader.conf.js

该文件的主要作用就是处理.vue文件，解析这个文件中的每个语言块（template、script、style),转换成js可用的js模块。

const utils = require('./utils')
const config = require('../config')
const isProduction = process.env.NODE_ENV === 'production'
const sourceMapEnabled = isProduction
 ? config.build.productionSourceMap
 : config.dev.cssSourceMap
//处理项目中的css文件，生产环境和测试环境默认是打开sourceMap，而extract中的提取样式到单独文件只有在生产环境中才需要
module.exports = {
 loaders: utils.cssLoaders({
 sourceMap: sourceMapEnabled,
 extract: isProduction
 }),
 cssSourceMap: sourceMapEnabled,
 cacheBusting: config.dev.cacheBusting,
// 在模版编译过程中，编译器可以将某些属性，如 src 路径，转换为require调用，以便目标资源可以由 webpack 处理
 transformToRequire: {
 video: ['src', 'poster'],
 source: 'src',
 img: 'src',
 image: 'xlink:href'
 }
}

webpack.base.conf.js

webpack.base.conf.js是开发和生产共同使用提出来的基础配置文件，主要实现配制入口，配置输出环境，配置模块resolve和插件等

const path = require('path')
const utils = require('./utils')
/**
* [引入index.js文件路径] 
*/
const config = require('../config')
const vueLoaderConfig = require('./vue-loader.conf')

/**
 * [获取文件路径]
 * @param dir [文件名称]
 *_dirname为当前模块文件所在目录的绝对路径* 
 *@return 文件绝对路径
*/
function resolve (dir) {
 return path.join(__dirname, '..', dir)
}
const createLintingRule = () => ({
 test: /\.(js|vue)$/,
 loader: 'eslint-loader',
 enforce: 'pre',
 include: [resolve('src'), resolve('test')],
 options: {
 formatter: require('eslint-friendly-formatter'),
 emitWarning: !config.dev.showEslintErrorsInOverlay
 }
})

module.exports = {
 context: path.resolve(__dirname, '../'),
 /**
 * [入口文件配置]
 */
 entry: {
/**
 * [入口文件路径, babel-polyfill是对es6语法的支持]
 */
 app: ['babel-polyfill', './src/main.js'],
 login: ['babel-polyfill', './src/loginMain.js'],
 license: ['babel-polyfill', './src/licenseMain.js']
 },
/**
 * [文件导出配置]
*/
 output: {
 path: config.build.assetsRoot,
 filename: '[name].js',
 publicPath: process.env.NODE_ENV === 'production'
 ? config.build.assetsPublicPath
 : config.dev.assetsPublicPath //公共存放路径
 },
 resolve: {
 /**
 * [extensions: 配置文件的扩展名,当在important文件时,不用需要添加扩展名]
 */
extensions: ['.js', '.vue', '.json'],
/**
 * [alias 给路径定义别名]
*/
 alias: {
 'vue$': 'vue/dist/vue.esm.js',
 '@': resolve('src')
 }
 },
/**
*使用插件配置相应文件的处理方法
*/
 module: {
rules: [
 ...(config.dev.useEslint ? [createLintingRule()] : []),
/**
 * [使用vue-loader将vue文件转化成js的模块]
*/
 {
 test: /\.vue$/,
 loader: 'vue-loader',
 options: vueLoaderConfig
 },
/**
 * [通过babel-loader将js进行编译成es5/es6 文件]
*/
 {
 test: /\.js$/,
 loader: 'babel-loader',
 include: [resolve('src'), resolve('test')]
 },
/**
 * [图片、音像、字体都使用url-loader进行处理，超过10000会编译成base64]
*/
 {
 test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
 loader: 'url-loader',
 options: {
 limit: 10000,
 name: utils.assetsPath('img/[name].[hash:7].[ext]')
 }
 },
 {
 test: /\.(mp4|webm|ogg|mp3|wav|flac|aac)(\?.*)?$/,
 loader: 'url-loader',
 options: {
 limit: 10000,
 name: utils.assetsPath('media/[name].[hash:7].[ext]')
 }
 },
 {
 test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
 loader: 'url-loader',
 options: {
 limit: 10000,
 name: utils.assetsPath('fonts/[name].[hash:7].[ext]')
 }
 },
/**
 * [canvas 解析]
*/
 {
 test: path.resolve(`${resolve('src')}/lib/jtopo.js`),
 loader: ['exports-loader?window.JTopo', 'script-loader']
 }
 ]
 },
//以下选项是Node.js全局变量或模块，这里主要是防止webpack注入一些Node.js的东西到vue中 
 node: {
 setImmediate: false,
 dgram: 'empty',
 fs: 'empty',
 net: 'empty', 
 tls: 'empty',
 child_process: 'empty'
 }
}

webpack.dev.conf.js

const path = require('path')
const utils = require('./utils')
const webpack = require('webpack')
const config = require('../config')
//通过webpack-merge实现webpack.dev.conf.js对wepack.base.config.js的继承
const merge = require('webpack-merge')
const baseWebpackConfig = require('./webpack.base.conf')
const HtmlWebpackPlugin = require('html-webpack-plugin')
//美化webpack的错误信息和日志的插件
const FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin')
// 查看空闲端口位置，默认情况下搜索8000这个端口
const portfinder = require('portfinder')
// processs为node的一个全局对象获取当前程序的环境变量，即host
const HOST = process.env.HOST
const PORT = process.env.PORT && Number(process.env.PORT)
function resolveApp(relativePath) {
 return path.resolve(relativePath);
}
const devWebpackConfig = merge(baseWebpackConfig, {
 module: {
//规则是工具utils中处理出来的styleLoaders，生成了css，less,postcss等规则
 rules: utils.styleLoaders({ sourceMap: config.dev.cssSourceMap, usePostCSS: true })
 },
// 增强调试
 devtool: config.dev.devtool,
// 此处的配置都是在config的index.js中设定好了
 devServer: {
//控制台显示的选项有none, error, warning 或者 info
clientLogLevel: 'warning',
//使用 HTML5 History API
historyApiFallback: true,
hot: true, //热加载
compress: true, //压缩
 host: HOST || config.dev.host,
port: PORT || config.dev.port,
open: config.dev.autoOpenBrowser, //调试时自动打开浏览器
 overlay: config.dev.errorOverlay
 ? { warnings: false, errors: true }
 : false,
 publicPath: config.dev.assetsPublicPath,
proxy: config.dev.proxyTable,//接口代理
quiet: true, //控制台是否禁止打印警告和错误,若用FriendlyErrorsPlugin 此处为 true watchOptions: {
 poll: config.dev.poll, // 文件系统检测改动
 }
 },
 plugins: [
 new webpack.DefinePlugin({
 'process.env': require('../config/dev.env')
 }),
new webpack.HotModuleReplacementPlugin(),//模块热替换插件，修改模块时不需要刷新页面
new webpack.NamedModulesPlugin(), // 显示文件的正确名字
new webpack.NoEmitOnErrorsPlugin(), //当webpack编译错误的时候，来中端打包进程，防止错误代码打包到文件中
// https://github.com/ampedandwired/html-webpack-plugin
// 该插件可自动生成一个 html5 文件或使用模板文件将编译好的代码注入进去 
new HtmlWebpackPlugin({
 filename: 'index.html',
 template: 'index.html',
 inject: true,
 chunks: ['app']
 }),
 new HtmlWebpackPlugin({
 filename: 'login.html',
 template: 'login.html',
 inject: true,
 chunks: ['login']
 }),
 new HtmlWebpackPlugin({
 filename: 'license.html',
 template: 'license.html',
 inject: true,
 chunks: ['license']
 }),
 new HtmlWebpackPlugin({
 filename: 'licenses.html',
 template: 'licenses.html',
 inject: true,
 chunks: []
 }),
 new HtmlWebpackPlugin({
 filename: '404.html',
 template: path.resolve(__dirname, '../errors/404.html'),
 favicon: resolveApp('favicon.ico'),
 inject: true,
 chunks: []
 }),
 new HtmlWebpackPlugin({
 filename: '403.html',
 template: path.resolve(__dirname, '../errors/403.html'),
 favicon: resolveApp('favicon.ico'),
 inject: true,
 chunks: []
 }),
 new HtmlWebpackPlugin({
 filename: '500.html',
 template: path.resolve(__dirname, '../errors/500.html'),
 favicon: resolveApp('favicon.ico'),
 inject: true,
 chunks: []
 })
 ]
})

module.exports = new Promise((resolve, reject) => {
 portfinder.basePort = process.env.PORT || config.dev.port
//查找端口号
 portfinder.getPort((err, port) => {
 if (err) {
 reject(err)
} else {
//端口被占用时就重新设置evn和devServer的端口
 process.env.PORT = port
 // add port to devServer config
 devWebpackConfig.devServer.port = port
//友好地

webpack.prod.conf.js

const path = require('path')
const utils = require('./utils')
const webpack = require('webpack')
const config = require('../config')
const merge = require('webpack-merge')
const baseWebpackConfig = require('./webpack.base.conf')
const CopyWebpackPlugin = require('copy-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')

const env = require('../config/prod.env')
function resolveApp(relativePath) {
 return path.resolve(relativePath);
}
const webpackConfig = merge(baseWebpackConfig, {
 module: {
 rules: utils.styleLoaders({
 sourceMap: config.build.productionSourceMap,//开启调试的模式。默认为true
 extract: true,
 usePostCSS: true
 })
 },
 devtool: config.build.productionSourceMap ? config.build.devtool : false,
 output: {
 path: config.build.assetsRoot,
 filename: utils.assetsPath('js/[name].[chunkhash].js'),
 chunkFilename: utils.assetsPath('js/[id].[chunkhash].js')
 },
 plugins: [
 // http://vuejs.github.io/vue-loader/en/workflow/production.html
 new webpack.DefinePlugin({
 'process.env': env
 }),
 new UglifyJsPlugin({
 uglifyOptions: {
 compress: {
 warnings: false //警告：true保留警告，false不保留
 }
 },
 sourceMap: config.build.productionSourceMap,
 parallel: true
 }),
// extract css into its own file
//抽取文本。比如打包之后的index页面有style插入，就是这个插件抽取出来的，减少请求
new ExtractTextPlugin({
 filename: utils.assetsPath('css/[name].[contenthash].css'),
 allChunks: true,
}),
//优化css的插件
 new OptimizeCSSPlugin({
 cssProcessorOptions: config.build.productionSourceMap
 ? { safe: true, map: { inline: false } }
 : { safe: true }
 }),
 //html打包
 new HtmlWebpackPlugin({
 filename: config.build.index,
 template: 'index.html',
 inject: true,
//压缩
 minify: {
 removeComments: true, //删除注释
 collapseWhitespace: true, //删除空格
 removeAttributeQuotes: true //删除属性的引号
 },
 chunks: ['vendor', 'manifest', 'app'],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 new HtmlWebpackPlugin({
 filename: config.build.login,
 template: 'login.html',
 inject: true,
 minify: {
 removeComments: true,
 collapseWhitespace: true,
 removeAttributeQuotes: true
 },
 chunks: ['vendor', 'manifest', 'login'],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 new HtmlWebpackPlugin({
 filename: config.build.license,
 template: 'license.html',
 inject: true,
 minify: {
 removeComments: true,
 collapseWhitespace: true,
 removeAttributeQuotes: true
 },
 chunks: ['vendor', 'manifest', 'license'],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 new HtmlWebpackPlugin({
 filename: config.build.notfound,
 template: path.resolve(__dirname, '../errors/404.html'),
 inject: true,
 favicon: resolveApp('favicon.ico'),
 minify: {
 removeComments: true,
 collapseWhitespace: true,
 removeAttributeQuotes: true
 },
 chunks: [],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 new HtmlWebpackPlugin({
 filename: config.build.forbidden,
 template: path.resolve(__dirname, '../errors/403.html'),
 inject: true,
 favicon: resolveApp('favicon.ico'),
 minify: {
 removeComments: true,
 collapseWhitespace: true,
 removeAttributeQuotes: true
 },
 chunks: [],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 new HtmlWebpackPlugin({
 filename: config.build.internal,
 template: path.resolve(__dirname, '../errors/500.html'),
 inject: true,
 favicon: resolveApp('favicon.ico'),
 minify: {
 removeComments: true,
 collapseWhitespace: true,
 removeAttributeQuotes: true
 },
 chunks: [],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 new HtmlWebpackPlugin({
 filename: config.build.licenses,
 template: 'licenses.html',
 inject: true,
 minify: {
 removeComments: true,
 collapseWhitespace: true,
 removeAttributeQuotes: true
 },
 chunks: [],
 // necessary to consistently work with multiple chunks via CommonsChunkPlugin
 chunksSortMode: 'dependency'
 }),
 // keep module.id stable when vender modules does not change
 new webpack.HashedModuleIdsPlugin(),
 // enable scope hoisting
new webpack.optimize.ModuleConcatenationPlugin(),
//抽取公共的模块, 提升你的代码在浏览器中的执行速度。
 new webpack.optimize.CommonsChunkPlugin({
 name: 'vendor',
 minChunks (module) {
 // any required modules inside node_modules are extracted to vendor
 return (
 module.resource &&
 /\.js$/.test(module.resource) &&
 module.resource.indexOf(
 path.join(__dirname, '../node_modules')
 ) === 0
 )
 }
 }),
 // extract webpack runtime and module manifest to its own file in order to
 // prevent vendor hash from being updated whenever app bundle is updated
 new webpack.optimize.CommonsChunkPlugin({
 name: 'manifest',
 minChunks: Infinity
}),
// 预编译所有模块到一个闭包中， 
 new webpack.optimize.CommonsChunkPlugin({
 name: 'app',
 async: 'vendor-async',
 children: true,
 minChunks: 3
 }),
//复制，比如打包完之后需要把打包的文件复制到dist里面
 new CopyWebpackPlugin([
 {
 from: path.resolve(__dirname, '../static'),
 to: config.build.assetsSubDirectory,
 ignore: ['.*']
 }
 ])
 ]
})

if (config.build.productionGzip) {
 const CompressionWebpackPlugin = require('compression-webpack-plugin')

 webpackConfig.plugins.push(
 new CompressionWebpackPlugin({
 asset: '[path].gz[query]',
 algorithm: 'gzip',
 test: new RegExp(
 '\\.(' +
 config.build.productionGzipExtensions.join('|') +
 ')$'
 ),
 threshold: 10240,
 minRatio: 0.8
 })
 )
}
// 提供带 Content-Encoding 编码的压缩版的资源
if (config.build.bundleAnalyzerReport) {
 const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
 webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}
module.exports = webpackConfig