Vue-webpack項目配置詳解

1、首先我們在構建vue項目后，就得先了解vue的項目結構

├── build --------------------------------- webpack相關配置文件
│   ├── build.js --------------------------webpack打包配置文件
│   ├── check-versions.js ------------------------------ 檢查npm,nodejs版本
│   ├── dev-client.js ---------------------------------- 設置環境
│   ├── dev-server.js ---------------------------------- 創建express服務器，配置中間件，啟動可熱重載的服務器，用于開發項目
│   ├── utils.js --------------------------------------- 配置資源路徑，配置css加載器
│   ├── vue-loader.conf.js ----------------------------- 配置css加載器等
│   ├── webpack.base.conf.js --------------------------- webpack基本配置
│   ├── webpack.dev.conf.js ---------------------------- 用于開發的webpack設置
│   ├── webpack.prod.conf.js --------------------------- 用于打包的webpack設置
├── config ---------------------------------- 配置文件
├── node_modules ---------------------------- 存放依賴的目錄
├── src ------------------------------------- 源碼
│   ├── assets ------------------------------ 靜態文件
│   ├── components -------------------------- 組件 
│   ├── main.js ----------------------------- 主js
│   ├── App.vue ----------------------------- 項目入口組件
│   ├── router ------------------------------ 路由
├── package.json ---------------------------- node配置文件
├── .babelrc--------------------------------- babel配置文件
├── .editorconfig---------------------------- 編輯器配置
├── .gitignore------------------------------- 配置git可忽略的文件

2、接下來我們來分析各個模塊的用處

先從dev-server.js開始

require('./check-versions')()   //檢查node和npm的版本/*獲取config/index.js中的默認配置，config后面沒有配置項會自動找index.js*/
var config = require('../config')/*如果Node環境無法判斷是dev還是product環境則使用config.dev.env.NODE_ENV作為當前執行環境*/
if (!process.env.NODE_ENV) {process.env.NODE_ENV = JSON.parse(config.dev.env.NODE_ENV)
}var opn = require('opn')    //一個可以強制打開瀏覽器并跳轉到指定url的插件var path = require('path')  //使用Node自帶的文件路徑工具var express = require('express')    //使用expressvar webpack = require('webpack')    //使用webpackvar proxyMiddleware = require('http-proxy-middleware')  //一個Node的代理中間件var webpackConfig = process.env.NODE_ENV === 'testing'? require('./webpack.prod.conf'): require('./webpack.dev.conf')//根據不同的Node環境加載不同的webpack配置// default port where dev server listens for incoming traffic,如果沒有指定端口就是用config.dev.port作為運行端口
var port = process.env.PORT || config.dev.port// automatically open browser, if not set will be false根據config.dev.autoOpenBrowser選擇是否自動打開瀏覽器
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 的配置作為 proxyTable 的代理配置var proxyTable = config.dev.proxyTablevar app = express()//使用express啟動一個服務var compiler = webpack(webpackConfig)//啟動webpack進行編譯// 啟動 webpack-dev-middleware，將 編譯后的文件暫存到內存中var devMiddleware = require('webpack-dev-middleware')(compiler, {publicPath: webpackConfig.output.publicPath,quiet: true
})// 啟動 webpack-hot-middleware，也就是我們常說的 Hot-reload,https://www.npmjs.com/package/webpack-hot-middlewarevar hotMiddleware = require('webpack-hot-middleware')(compiler, {log: () => {},heartbeat: 2000
})// 當html-webpack-plugin模板更改時，強制頁面重新加載compiler.plugin('compilation', function (compilation) {compilation.plugin('html-webpack-plugin-after-emit', function (data, cb) {hotMiddleware.publish({ action: 'reload' })cb()})
})// proxy api requests
//將 proxyTable 中的請求配置掛在到啟動的 express 服務上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 匹配資源，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
//將暫存到內存中的 webpack 編譯后的文件掛在到 express 服務上app.use(devMiddleware)// enable hot-reload and state-preserving
// compilation error display
//將 Hot-reload 掛在到 express 服務上app.use(hotMiddleware)// serve pure static assets
//拼接 static 文件夾的靜態資源路徑var staticPath = path.posix.join(config.dev.assetsPublicPath, config.dev.assetsSubDirectory)app.use(staticPath, express.static('./static'))// 讓我們這個 express 服務監聽 port 的請求，并且將此服務作為 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// 如果不是測試環境，自動打開瀏覽器并跳到我們的開發地址if (autoOpenBrowser && process.env.NODE_ENV !== 'testing') {opn(uri)}_resolve()
})var server = app.listen(port)
module.exports = {ready: readyPromise,close: () => {server.close()}
}

這個文件引用了三個配置文件,分別是config/index.js,webpack.prod.conf.js,
webpack.dev.conf.js,那我們就直接按照先后順序來吧.

index.js

// see http://vuejs-templates.github.io/webpack for documentation.var path = require('path')//使用Node自帶的文件路徑插件
module.exports = {//生產環境配置build: {//http://vuejs-templates.github.io/webpack/backend.html// 使用 config/prod.env.js 中定義的編譯環境env: require('./prod.env'),index: path.resolve(__dirname, '../dist/index.html'),   // 編譯注入的 index.html 文件,必須是本地的絕對路徑assetsRoot: path.resolve(__dirname, '../dist'),   // 編譯輸出的靜態資源根路徑assetsSubDirectory: 'static',    // 編譯輸出的二級目錄assetsPublicPath: '/',    // 編譯發布上線路徑的根目錄，可配置為資源服務器域名或 CDN 域名productionSourceMap: true,    //生成用于生產構建的源映射// 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,    // 是否開啟 gzipproductionGzipExtensions: ['js', 'css'],    // 需要使用 gzip 壓縮的文件擴展名// 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    //一個實用工具,用于分析項目的依賴關系https://www.npmjs.com/package/webpack-bundle-analyzer},//開發環境dev: {env: require('./dev.env'),    // 使用 config/dev.env.js 中定義的編譯環境port: 8080,    // 運行測試頁面的端口autoOpenBrowser: true,    //是否自動打開瀏覽器assetsSubDirectory: 'static',    // 編譯輸出的二級目錄assetsPublicPath: '/',    // 編譯發布上線路徑的根目錄，可配置為資源服務器域名或 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   // 是否開啟 cssSourceMap}
}

注:更詳細的配置項請參考gitbook上的介紹

webpack.base.conf.js

這是基本配置，后面可以通過webpack-merge,將基本配置和不同環境的配置合并到一起,避免代碼重復。

var path = require('path')   // 使用 NodeJS 自帶的文件路徑插件var utils = require('./utils')   //封裝了一些方法的工具var config = require('../config')   //使用 config/index.jsvar vueLoaderConfig = require('./vue-loader.conf')   //使用
vue-loader.conf// 拼接我們的工作區路徑為一個絕對路徑
function resolve (dir) {return path.join(__dirname, '..', dir)
}module.exports = {entry: {// 編譯文件入口app: './src/main.js'},output: {//使用chonfig/index.js中build的assetsRoot作為輸出根路徑path: config.build.assetsRoot,filename: '[name].js',    //編譯輸入的文件名publicPath: process.env.NODE_ENV === 'production'    // 正式發布環境下編譯輸出的發布路徑? config.build.assetsPublicPath: config.dev.assetsPublicPath},resolve: {    //https://doc.webpack-china.org/configuration/resolve/// 自動補全的擴展名,能夠使用戶在引入模塊時不帶擴展extensions: ['.js', '.vue', '.json'],// 默認路徑代理，例如 import Vue from 'vue$'，會自動到 'vue/dist/vue.esm.js'中尋找alias: {'vue$': '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///模塊的規則數組,詳情請參考上述鏈接的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:詳細的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')   //...//可以將單個文件或整個目錄復制到構建目錄中var CopyWebpackPlugin = require('copy-webpack-plugin')// 一個可以插入 html 并且創建新的 .html 文件的插件var HtmlWebpackPlugin = require('html-webpack-plugin')// 一個 webpack 擴展，可以提取一些代碼并且將它們和文件分離開
// 如果我們想將 webpack 打包成一個文件 css js 分離開，那我們需要這個插件var ExtractTextPlugin = require('extract-text-webpack-plugin')//一個個優化/最小化css資源的插件var OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')var env = process.env.NODE_ENV === 'testing'? require('../config/test.env'): config.build.env//如果不是測試環境就直接使用生產環境//合并 webpack.base.conf.js中的配置,里面具體的配置參考webpack.base.conf.js里面的注釋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,   //指定生產環境輸出路徑filename: utils.assetsPath('js/[name].[chunkhash].js'),    //編譯輸出帶hash的文件名,可以指定hash長度(chunkhash:6)chunkFilename: utils.assetsPath('js/[id].[chunkhash].js')    // 沒有指定輸出名的文件輸出的文件名},plugins: [// http://vuejs.github.io/vue-loader/en/workflow/production.html// definePlugin 接收字符串插入到代碼當中, 所以你需要的話可以寫上 JS 的字符串new webpack.DefinePlugin({'process.env': env}),// 壓縮 js (同樣可以壓縮 css)new webpack.optimize.UglifyJsPlugin({compress: {warnings: false},sourceMap: true}),// extract css into its own file//將 css 文件分離出來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.//壓縮css代碼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// 輸入輸出的 .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: {    // 壓縮的方式removeComments: true,    //移除帶html的注釋collapseWhitespace: true,    //移除空格removeAttributeQuotes: true   //移除屬性的引號// 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'    //資源按照依賴關系去插入}),// split vendor js into its own file//將引用的庫文件拆出來打包到一個[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//任何一個從node_modules中引用的模塊都會被打包進來return (module.resource &&/\.js$/.test(module.resource) &&module.resource.indexOf(path.join(__dirname, '../node_modules')) === 0)}}),// extract webpack runtime and module manifest to its own file in order to// prevent vendor hash from being updated whenever app bundle is updated//https://doc.webpack-china.org/concepts/manifest///把webpack的runtime和manifest這些webpack管理所有模塊交互的代碼打包到[name].js文件中,防止build之后vendor的hash值被更新new webpack.optimize.CommonsChunkPlugin({name: 'manifest',chunks: ['vendor']}),// copy custom static assets//復制自定義的靜態資源文件到dist/static文件夾中new CopyWebpackPlugin([{from: path.resolve(__dirname, '../static'),to: config.build.assetsSubDirectory,ignore: ['.*']}])]
})// 開啟 gzip 的情況下使用下方的配置if (config.build.productionGzip) {// Gzip依賴 compression-webpack-plugin 插件var CompressionWebpackPlugin = require('compression-webpack-plugin')// 向webpackconfig.plugins中加入下方的插件webpackConfig.plugins.push(// 使用 compression-webpack-plugin 插件進行壓縮,https://doc.webpack-china.org/plugins/compression-webpack-plugin/new CompressionWebpackPlugin({asset: '[path].gz[query]',//目標資源名稱algorithm: 'gzip',//壓縮方式test: new RegExp('\\.(' +config.build.productionGzipExtensions.join('|') +')$'),//所有匹配該正則的資源都會被處理。默認值是全部資源。threshold: 10240,//只有大小大于該值的資源會被處理。單位是 bytes。默認值是 0。minRatio: 0.8//只有壓縮率小于這個值的資源才會被處理。默認值是 0.8。}))
}//配置項目分析工具加載下方插件
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')//封裝了一些方法的工具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')// 加載 webpack.base.confvar HtmlWebpackPlugin = require('html-webpack-plugin')// 使用 html-webpack-plugin 插件，這個插件可以幫我們自動生成 html 并且注入到 .html 文件中//https://www.npmjs.com/package/friendly-errors-webpack-plugin,可以識別某些類別的Webpack錯誤并進行清理，聚合和優先排序
var FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin')// add hot-reload related code to entry chunks
//將 Hol-reload 相對路徑添加到 webpack.base.conf 的 對應 entry 前
Object.keys(baseWebpackConfig.entry).forEach(function (name) {baseWebpackConfig.entry[name] = ['./build/dev-client'].concat(baseWebpackConfig.entry[name])
})// 將我們 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 模式作為開發輔助調試工具// 具體配置請參考https://doc.webpack-china.org/configuration/devtool/devtool: '#cheap-module-eval-source-map',plugins: [// definePlugin 接收字符串插入到代碼當中, 需要的話可以寫上 JS 的字符串new webpack.DefinePlugin({'process.env': config.dev.env}),// https://github.com/glenjamin/webpack-hot-middleware#installation--usage// HotModule 插件在頁面進行變更的時候只會重回對應的頁面模塊，不會重繪整個 html 文件new webpack.HotModuleReplacementPlugin(),//https://doc.webpack-china.org/plugins/no-emit-on-errors-plugin///在編譯出現錯誤時，使用 NoEmitOnErrorsPlugin 來跳過輸出階段。這樣可以確保輸出資源不會包含錯誤。new webpack.NoEmitOnErrorsPlugin(),// https://github.com/ampedandwired/html-webpack-plugin// 將 index.html 作為入口，注入 html 代碼后生成 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')()// 檢查 Node 和 npm 版本
process.env.NODE_ENV = 'production'//指定生產環境
var ora = require('ora')// 一個很好看的 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自帶的文件路徑插件
var chalk = require('chalk')//控制臺高亮顯示的插件
var webpack = require('webpack')//使用 webpack
var config = require('../config')//使用 config/index.js
var webpackConfig = require('./webpack.prod.conf')// 加載 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//如果回調函數出現錯誤就拋出異常//  開始 webpack 的編譯webpack(webpackConfig, function (err, stats) {//編譯回調函數spinner.stop()if (err) throw err//編譯失敗就拋出異常process.stdout.write(stats.toString({//標準輸出流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依賴的webpack.prod.conf.js已經在上面介紹了,所以翻上去看看吧.

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

這三個js里面的代碼比較簡單,就是輸出了三個不同的node環境, 分別對應開發環境, 生產環境, 測試環境.

check-versions.js

這里面的代碼主要是通過調用shell去打印出node和npm的版本信息,同時會給出版本依賴的警告信息.

var chalk = require('chalk')// 用于在控制臺輸出高亮字體的插件
var semver = require('semver')// 語義化版本檢查插件
var packageConfig = require('../package.json')// 引入package.json
var shell = require('shelljs')//引入shelljs
// 開辟子進程執行指令cmd并返回結果
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 = []// 依次判斷版本是否符合要求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('')// 如果有警告則將其輸出到控制臺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)}
}