Vue-webpack项目配置详解

1、首先我们在构建vue项目后，就得先了解vue的项目结构

├── build --------------------------------- webpack相关配置文件
│   ├── build.js --------------------------webpack打包配置文件
│   ├── check-versions.js ------------------------------ 检查npm,nodejs版本
│   ├── dev-client.js ---------------------------------- 设置环境
│   ├── dev-server.js ---------------------------------- 创建express服务器，配置中间件，启动可热重载的服务器，用于开发项目
│   ├── utils.js --------------------------------------- 配置资源路径，配置css加载器
│   ├── vue-loader.conf.js ----------------------------- 配置css加载器等
│   ├── webpack.base.conf.js --------------------------- webpack基本配置
│   ├── webpack.dev.conf.js ---------------------------- 用于开发的webpack设置
│   ├── webpack.prod.conf.js --------------------------- 用于打包的webpack设置
├── config ---------------------------------- 配置文件
├── node_modules ---------------------------- 存放依赖的目录
├── src ------------------------------------- 源码
│   ├── assets ------------------------------ 静态文件
│   ├── components -------------------------- 组件 
│   ├── main.js ----------------------------- 主js
│   ├── App.vue ----------------------------- 项目入口组件
│   ├── router ------------------------------ 路由
├── package.json ---------------------------- node配置文件
├── .babelrc--------------------------------- babel配置文件
├── .editorconfig---------------------------- 编辑器配置
├── .gitignore------------------------------- 配置git可忽略的文件

2、接下来我们来分析各个模块的用处

先从dev-server.js开始

require('./check-versions')()   //检查node和npm的版本/*获取config/index.js中的默认配置，config后面没有配置项会自动找index.js*/
var config = require('../config')/*如果Node环境无法判断是dev还是product环境则使用config.dev.env.NODE_ENV作为当前执行环境*/
if (!process.env.NODE_ENV) {process.env.NODE_ENV = JSON.parse(config.dev.env.NODE_ENV)
}var opn = require('opn')    //一个可以强制打开浏览器并跳转到指定url的插件var path = require('path')  //使用Node自带的文件路径工具var express = require('express')    //使用expressvar webpack = require('webpack')    //使用webpackvar proxyMiddleware = require('http-proxy-middleware')  //一个Node的代理中间件var webpackConfig = process.env.NODE_ENV === 'testing'? require('./webpack.prod.conf'): require('./webpack.dev.conf')//根据不同的Node环境加载不同的webpack配置// default port where dev server listens for incoming traffic,如果没有指定端口就是用config.dev.port作为运行端口
var port = process.env.PORT || config.dev.port// automatically open browser, if not set will be false根据config.dev.autoOpenBrowser选择是否自动打开浏览器
var autoOpenBrowser = !!config.dev.autoOpenBrowser// Define HTTP proxies to your custom API backend
// https://github.com/chimurai/http-proxy-middleware
//使用 config.dev.proxyTable 的配置作为 proxyTable 的代理配置var proxyTable = config.dev.proxyTablevar app = express()//使用express启动一个服务var compiler = webpack(webpackConfig)//启动webpack进行编译// 启动 webpack-dev-middleware，将 编译后的文件暂存到内存中var devMiddleware = require('webpack-dev-middleware')(compiler, {publicPath: webpackConfig.output.publicPath,quiet: true
})// 启动 webpack-hot-middleware，也就是我们常说的 Hot-reload,https://www.npmjs.com/package/webpack-hot-middlewarevar hotMiddleware = require('webpack-hot-middleware')(compiler, {log: () => {},heartbeat: 2000
})// 当html-webpack-plugin模板更改时，强制页面重新加载compiler.plugin('compilation', function (compilation) {compilation.plugin('html-webpack-plugin-after-emit', function (data, cb) {hotMiddleware.publish({ action: 'reload' })cb()})
})// proxy api requests
//将 proxyTable 中的请求配置挂在到启动的 express 服务上Object.keys(proxyTable).forEach(function (context) {var options = proxyTable[context]if (typeof options === 'string') {options = { target: options }}app.use(proxyMiddleware(options.filter || context, options))
})// handle fallback for HTML5 history API
//使用 connect-history-api-fallback 匹配资源，如果不匹配就可以重定向到指定地址
// https://www.npmjs.com/package/connect-history-api-fallbackapp.use(require('connect-history-api-fallback')())// serve webpack bundle output
//将暂存到内存中的 webpack 编译后的文件挂在到 express 服务上app.use(devMiddleware)// enable hot-reload and state-preserving
// compilation error display
//将 Hot-reload 挂在到 express 服务上app.use(hotMiddleware)// serve pure static assets
//拼接 static 文件夹的静态资源路径var staticPath = path.posix.join(config.dev.assetsPublicPath, config.dev.assetsSubDirectory)app.use(staticPath, express.static('./static'))// 让我们这个 express 服务监听 port 的请求，并且将此服务作为 dev-server.js 的接口暴露出去var uri = 'http://localhost:' + portvar _resolvevar readyPromise = new Promise(resolve => {_resolve = resolve
})console.log('> Starting dev server...')devMiddleware.waitUntilValid(() => {console.log('> Listening at ' + uri + '\n')// when env is testing, don't need open it// 如果不是测试环境，自动打开浏览器并跳到我们的开发地址if (autoOpenBrowser && process.env.NODE_ENV !== 'testing') {opn(uri)}_resolve()
})var server = app.listen(port)
module.exports = {ready: readyPromise,close: () => {server.close()}
}

这个文件引用了三个配置文件,分别是config/index.js,webpack.prod.conf.js,
webpack.dev.conf.js,那我们就直接按照先后顺序来吧.

index.js

// see http://vuejs-templates.github.io/webpack for documentation.var path = require('path')//使用Node自带的文件路径插件
module.exports = {//生产环境配置build: {//http://vuejs-templates.github.io/webpack/backend.html// 使用 config/prod.env.js 中定义的编译环境env: require('./prod.env'),index: path.resolve(__dirname, '../dist/index.html'),   // 编译注入的 index.html 文件,必须是本地的绝对路径assetsRoot: path.resolve(__dirname, '../dist'),   // 编译输出的静态资源根路径assetsSubDirectory: 'static',    // 编译输出的二级目录assetsPublicPath: '/',    // 编译发布上线路径的根目录，可配置为资源服务器域名或 CDN 域名productionSourceMap: true,    //生成用于生产构建的源映射// Gzip off by default as many popular static hosts such as// Surge or Netlify already gzip all static assets for you.// Before setting to `true`, make sure to:// npm install --save-dev compression-webpack-pluginproductionGzip: false,    // 是否开启 gzipproductionGzipExtensions: ['js', 'css'],    // 需要使用 gzip 压缩的文件扩展名// Run the build command with an extra argument to// View the bundle analyzer report after build finishes:// `npm run build --report`// Set to `true` or `false` to always turn it on or offbundleAnalyzerReport: process.env.npm_config_report    //一个实用工具,用于分析项目的依赖关系https://www.npmjs.com/package/webpack-bundle-analyzer},//开发环境dev: {env: require('./dev.env'),    // 使用 config/dev.env.js 中定义的编译环境port: 8080,    // 运行测试页面的端口autoOpenBrowser: true,    //是否自动打开浏览器assetsSubDirectory: 'static',    // 编译输出的二级目录assetsPublicPath: '/',    // 编译发布上线路径的根目录，可配置为资源服务器域名或 CDN 域名proxyTable: {//https://github.com/chimurai/http-proxy-middleware,配置方式},    // 需要 proxyTable 代理的接口（可跨域）http://vuejs-templates.github.io/webpack/proxy.html// CSS Sourcemaps off by default because relative paths are "buggy"// with this option, according to the CSS-Loader README// (https://github.com/webpack/css-loader#sourcemaps)// In our experience, they generally work as expected,// just be aware of this issue when enabling this option.cssSourceMap: false   // 是否开启 cssSourceMap}
}

注:更详细的配置项请参考gitbook上的介绍

webpack.base.conf.js

这是基本配置，后面可以通过webpack-merge,将基本配置和不同环境的配置合并到一起,避免代码重复。

var path = require('path')   // 使用 NodeJS 自带的文件路径插件var utils = require('./utils')   //封装了一些方法的工具var config = require('../config')   //使用 config/index.jsvar vueLoaderConfig = require('./vue-loader.conf')   //使用
vue-loader.conf// 拼接我们的工作区路径为一个绝对路径
function resolve (dir) {return path.join(__dirname, '..', dir)
}module.exports = {entry: {// 编译文件入口app: './src/main.js'},output: {//使用chonfig/index.js中build的assetsRoot作为输出根路径path: config.build.assetsRoot,filename: '[name].js',    //编译输入的文件名publicPath: process.env.NODE_ENV === 'production'    // 正式发布环境下编译输出的发布路径? config.build.assetsPublicPath: config.dev.assetsPublicPath},resolve: {    //https://doc.webpack-china.org/configuration/resolve/// 自动补全的扩展名,能够使用户在引入模块时不带扩展extensions: ['.js', '.vue', '.json'],// 默认路径代理，例如 import Vue from 'vue$'，会自动到 'vue/dist/vue.esm.js'中寻找alias: {'vue$': 'vue/dist/vue.esm.js','@': resolve('src')}},module: {    //https://doc.webpack-china.org/loaders/ loader列表rules: [   //https://doc.webpack-china.org/configuration/module///模块的规则数组,详情请参考上述链接的loader列表{test: /\.(js|vue)$/,//loader: 'eslint-loader',enforce: 'pre',include: [resolve('src'), resolve('test')],options: {formatter: require('eslint-friendly-formatter')}},{test: /\.vue$/,loader: 'vue-loader',options: vueLoaderConfig},{test: /\.js$/,loader: 'babel-loader',include: [resolve('src'), resolve('test')]},{test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,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]')}}]}
}

注:详细的loader列表可以到webpack的loaders去查看

webpack.prod.conf.js

var path = require('path')  //...var utils = require('./utils')   //...var webpack = require('webpack')   //...var config = require('../config')   //...var merge = require('webpack-merge')   //...var baseWebpackConfig = 
require('./webpack.base.conf')   //...//可以将单个文件或整个目录复制到构建目录中var CopyWebpackPlugin = require('copy-webpack-plugin')// 一个可以插入 html 并且创建新的 .html 文件的插件var HtmlWebpackPlugin = require('html-webpack-plugin')// 一个 webpack 扩展，可以提取一些代码并且将它们和文件分离开
// 如果我们想将 webpack 打包成一个文件 css js 分离开，那我们需要这个插件var ExtractTextPlugin = require('extract-text-webpack-plugin')//一个个优化/最小化css资源的插件var OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')var env = process.env.NODE_ENV === 'testing'? require('../config/test.env'): config.build.env//如果不是测试环境就直接使用生产环境//合并 webpack.base.conf.js中的配置,里面具体的配置参考webpack.base.conf.js里面的注释var webpackConfig = merge(baseWebpackConfig, {module: {rules: utils.styleLoaders({sourceMap: config.build.productionSourceMap,extract: true})},devtool: config.build.productionSourceMap ? '#source-map' : false,output: {path: config.build.assetsRoot,   //指定生产环境输出路径filename: utils.assetsPath('js/[name].[chunkhash].js'),    //编译输出带hash的文件名,可以指定hash长度(chunkhash:6)chunkFilename: utils.assetsPath('js/[id].[chunkhash].js')    // 没有指定输出名的文件输出的文件名},plugins: [// http://vuejs.github.io/vue-loader/en/workflow/production.html// definePlugin 接收字符串插入到代码当中, 所以你需要的话可以写上 JS 的字符串new webpack.DefinePlugin({'process.env': env}),// 压缩 js (同样可以压缩 css)new webpack.optimize.UglifyJsPlugin({compress: {warnings: false},sourceMap: true}),// extract css into its own file//将 css 文件分离出来new ExtractTextPlugin({filename: utils.assetsPath('css/[name].[contenthash].css')}),// Compress extracted CSS. We are using this plugin so that possible// duplicated CSS from different components can be deduped.//压缩css代码new OptimizeCSSPlugin({cssProcessorOptions: {safe: true}}),// generate dist index.html with correct asset hash for caching.// you can customize output by editing /index.html// see https://github.com/ampedandwired/html-webpack-plugin// 输入输出的 .html 文件new HtmlWebpackPlugin({filename: process.env.NODE_ENV === 'testing'? 'index.html': config.build.index,template: 'index.html',inject: true,     // 是否注入 htmlminify: {    // 压缩的方式removeComments: true,    //移除带html的注释collapseWhitespace: true,    //移除空格removeAttributeQuotes: true   //移除属性的引号// more options:// https://github.com/kangax/html-minifier#options-quick-reference},// necessary to consistently work with multiple chunks via CommonsChunkPlugin//https://doc.webpack-china.org/plugins/commons-chunk-plugin/chunksSortMode: 'dependency'    //资源按照依赖关系去插入}),// split vendor js into its own file//将引用的库文件拆出来打包到一个[name].js文件中new webpack.optimize.CommonsChunkPlugin({name: 'vendor',minChunks: function (module, count) {// any required modules inside node_modules are extracted to vendor//任何一个从node_modules中引用的模块都会被打包进来return (module.resource &&/\.js$/.test(module.resource) &&module.resource.indexOf(path.join(__dirname, '../node_modules')) === 0)}}),// extract webpack runtime and module manifest to its own file in order to// prevent vendor hash from being updated whenever app bundle is updated//https://doc.webpack-china.org/concepts/manifest///把webpack的runtime和manifest这些webpack管理所有模块交互的代码打包到[name].js文件中,防止build之后vendor的hash值被更新new webpack.optimize.CommonsChunkPlugin({name: 'manifest',chunks: ['vendor']}),// copy custom static assets//复制自定义的静态资源文件到dist/static文件夹中new CopyWebpackPlugin([{from: path.resolve(__dirname, '../static'),to: config.build.assetsSubDirectory,ignore: ['.*']}])]
})// 开启 gzip 的情况下使用下方的配置if (config.build.productionGzip) {// Gzip依赖 compression-webpack-plugin 插件var CompressionWebpackPlugin = require('compression-webpack-plugin')// 向webpackconfig.plugins中加入下方的插件webpackConfig.plugins.push(// 使用 compression-webpack-plugin 插件进行压缩,https://doc.webpack-china.org/plugins/compression-webpack-plugin/new CompressionWebpackPlugin({asset: '[path].gz[query]',//目标资源名称algorithm: 'gzip',//压缩方式test: new RegExp('\\.(' +config.build.productionGzipExtensions.join('|') +')$'),//所有匹配该正则的资源都会被处理。默认值是全部资源。threshold: 10240,//只有大小大于该值的资源会被处理。单位是 bytes。默认值是 0。minRatio: 0.8//只有压缩率小于这个值的资源才会被处理。默认值是 0.8。}))
}//配置项目分析工具加载下方插件
if (config.build.bundleAnalyzerReport) {var BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPluginwebpackConfig.plugins.push(new BundleAnalyzerPlugin())
}
module.exports = webpackConfig

webpack.dev.conf.js

var utils = require('./utils')//封装了一些方法的工具var webpack = require('webpack')//使用 webpackvar config = require('../config')//使用 config/index.jsvar merge = require('webpack-merge')//使用 webpack 配置合并插件var baseWebpackConfig = require('./webpack.base.conf')// 加载 webpack.base.confvar HtmlWebpackPlugin = require('html-webpack-plugin')// 使用 html-webpack-plugin 插件，这个插件可以帮我们自动生成 html 并且注入到 .html 文件中//https://www.npmjs.com/package/friendly-errors-webpack-plugin,可以识别某些类别的Webpack错误并进行清理，聚合和优先排序
var FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin')// add hot-reload related code to entry chunks
//将 Hol-reload 相对路径添加到 webpack.base.conf 的 对应 entry 前
Object.keys(baseWebpackConfig.entry).forEach(function (name) {baseWebpackConfig.entry[name] = ['./build/dev-client'].concat(baseWebpackConfig.entry[name])
})// 将我们 webpack.dev.conf.js 的配置和 webpack.base.conf.js 的配置合并
module.exports = merge(baseWebpackConfig, {module: {// 使用 styleLoadersrules: utils.styleLoaders({ sourceMap: config.dev.cssSourceMap })},// 使用 #cheap-module-eval-source-map 模式作为开发辅助调试工具// 具体配置请参考https://doc.webpack-china.org/configuration/devtool/devtool: '#cheap-module-eval-source-map',plugins: [// definePlugin 接收字符串插入到代码当中, 需要的话可以写上 JS 的字符串new webpack.DefinePlugin({'process.env': config.dev.env}),// https://github.com/glenjamin/webpack-hot-middleware#installation--usage// HotModule 插件在页面进行变更的时候只会重回对应的页面模块，不会重绘整个 html 文件new webpack.HotModuleReplacementPlugin(),//https://doc.webpack-china.org/plugins/no-emit-on-errors-plugin///在编译出现错误时，使用 NoEmitOnErrorsPlugin 来跳过输出阶段。这样可以确保输出资源不会包含错误。new webpack.NoEmitOnErrorsPlugin(),// https://github.com/ampedandwired/html-webpack-plugin// 将 index.html 作为入口，注入 html 代码后生成 index.html文件//https://doc.webpack-china.org/plugins/html-webpack-plugin/ webpack插件列表(中文)new HtmlWebpackPlugin({filename: 'index.html',template: 'index.html',inject: true}),//看上面new FriendlyErrorsPlugin()]
})

build.js

require('./check-versions')()// 检查 Node 和 npm 版本
process.env.NODE_ENV = 'production'//指定生产环境
var ora = require('ora')// 一个很好看的 loading 插件
var rm = require('rimraf')//提供node版本的UNIX的rm -rf命令
var path = require('path')//使用Node自带的文件路径插件
var chalk = require('chalk')//控制台高亮显示的插件
var webpack = require('webpack')//使用 webpack
var config = require('../config')//使用 config/index.js
var webpackConfig = require('./webpack.prod.conf')// 加载 webpack.prod.conf
// 使用 ora 打印出 loading + log
var spinner = ora('building for production...')
spinner.start()
//https://www.npmjs.com/package/rimraf
rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {if (err) throw err//如果回调函数出现错误就抛出异常//  开始 webpack 的编译webpack(webpackConfig, function (err, stats) {//编译回调函数spinner.stop()if (err) throw err//编译失败就抛出异常process.stdout.write(stats.toString({//标准输出流colors: true,modules: false,children: false,chunks: false,chunkModules: false}) + '\n\n')console.log(chalk.cyan('  Build complete.\n'))console.log(chalk.yellow('  Tip: built files are meant to be served over an HTTP server.\n' +'  Opening index.html over file:// won\'t work.\n'))})
})

build.js依赖的webpack.prod.conf.js已经在上面介绍了,所以翻上去看看吧.

dev.env.js, prod.env.js, test.env.js

这三个js里面的代码比较简单,就是输出了三个不同的node环境, 分别对应开发环境, 生产环境, 测试环境.

check-versions.js

这里面的代码主要是通过调用shell去打印出node和npm的版本信息,同时会给出版本依赖的警告信息.

var chalk = require('chalk')// 用于在控制台输出高亮字体的插件
var semver = require('semver')// 语义化版本检查插件
var packageConfig = require('../package.json')// 引入package.json
var shell = require('shelljs')//引入shelljs
// 开辟子进程执行指令cmd并返回结果
function exec (cmd) {return require('child_process').execSync(cmd).toString().trim()
}
// node和npm版本需求
var versionRequirements = [{name: 'node',currentVersion: semver.clean(process.version),versionRequirement: packageConfig.engines.node},
]
if (shell.which('npm')) {versionRequirements.push({name: 'npm',currentVersion: exec('npm --version'),versionRequirement: packageConfig.engines.npm})
}
module.exports = function () {var warnings = []// 依次判断版本是否符合要求for (var i = 0; i < versionRequirements.length; i++) {var mod = versionRequirements[i]if (!semver.satisfies(mod.currentVersion, mod.versionRequirement)) {warnings.push(mod.name + ': ' +chalk.red(mod.currentVersion) + ' should be ' +chalk.green(mod.versionRequirement))}}if (warnings.length) {console.log('')// 如果有警告则将其输出到控制台console.log(chalk.yellow('To use this template, you must update following to modules:'))console.log()for (var i = 0; i < warnings.length; i++) {var warning = warnings[i]console.log('  ' + warning)}console.log()process.exit(1)}
}