背景
按照 Ant Design 官網用 React 腳手構建的后台項目，剛接手項目的時候大概30條路由左右，我的用的機子是 Mac 8G 內存，打包完成需要耗時2分鍾左右，決定優化一下。
項目技術棧： React + React Router + TypeScript + Ant Design
構建時間慢可能的原因：
-
React 腳手架默認打包構建出來的文件包含 map 文件
-
Ant Desigin 以及項目中使用的第三方模塊太大
-
-
npm run rject 暴露出 Webpack 配置信息，直接進行修改。
-
使用 react-app-rewired （一個對 create-react-app 進行自定義配置的社區解決方案）Ant Design 官網推薦。
自定義Webpack配置步驟：
-
基礎配置
-
開發環境配置
-
npm i react-app-rewired customize-cra --save-dev 安裝 react-app-rewired ,customize-cra，它提供一些修改 React 腳手架默認配置函數,具體參見：https://github.com/arackaf/customize-cra
安裝后，修改 package.json 文件的
"scripts": { "start": "react-app-rewired start", "build": "react-app-rewired build", "test": "react-app-rewired test", }
項目根目錄創建一個 config-overrides.js 用於修改Webpack 配置。
Ant Desigin 提供了一個按需加載的 babel 插件
安裝 npm i babel-plugin-import --save-dev,並修改config-overrides.js 配置文件
override函數用來覆蓋React腳手架Webpack配置；fixBabelImports修改
const { override, fixBabelImports，addWebpackPlugin } = require('customize-cra');
const AntdDayjsWebpackPlugin = require('antd-dayjs-webpack-plugin');
module.exports = override(
fixBabelImports('import', {
libraryName: 'antd',
libraryDirectory: 'es',
style: 'css',
}),
addWebpackPlugin(new AntdDayjsWebpackPlugin())
);
以上是Ant Desigin推薦的做法。
2、首屏加載優化
npm i react-loadable customize-cra --save安裝react-loadable模塊,然后在路由文件里使用如下，loading組件可以自定義。這樣打包的時候會為每個路由生成一個chunk，以此來實現組件的動態加載。
需要安裝"@babel/plugin-syntax-dynamic-import這個插件，編譯import()這種語法
import Loadable from 'react-loadable'; const Index = Loadable({ loader:() => import('../components/Index'), loading:SpinLoading });
3、去掉 map 文件
首先安裝依賴包webpack-stats-plugin webpack-bundle-analyzer 前者為了統計打包時間會在打包后的文件夾里生成一個stats.json文件，后者用來分析打包后的各個模塊的大小。
process.env.GENERATE_SOURCEMAP = "false";用來去掉打包后的map文件
const { override, fixBabelImports } = require('customize-cra');
const { StatsWriterPlugin } = require("webpack-stats-plugin");
const AntdDayjsWebpackPlugin = require('antd-dayjs-webpack-plugin');
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
let startTime = Date.now()
if(process.env.NODE_ENV === 'production') process.env.GENERATE_SOURCEMAP = "false"
// 自定義生產環境配置
const productionConfig = (config) =>{
if(config.mode === 'production'){
config.plugins.push(...[
new StatsWriterPlugin({
fields: null,
transform: (data) => {
let endTime = Date.now()
data = {
Time: (endTime - startTime)/1000 + 's'
}
return JSON.stringify(data, null, 2);
}
}),
new BundleAnalyzerPlugin()
])
}
return config
}
module.exports = override(
productionConfig,
fixBabelImports('import', {
libraryName: 'antd',
libraryDirectory: 'es',
style: 'css',
}),
addWebpackPlugin(new AntdDayjsWebpackPlugin())
);
去掉map文件的打包時間，大約60s左右。查看打包后生成的分析圖發現Ant Desigin的一些組件被重復打包，打包出來一共有13M多。
4、更細化分包
在productionConfig配置添加，在入口文件添加vendors用來分離穩定不變的模塊；common用來抽離復用模塊；styles將css文件抽離成一個文件；
// 針對生產環境修改配置 const productionConfig = (config) =>{ if(config.mode === 'production'){ const splitChunksConfig = config.optimization.splitChunks; if (config.entry && config.entry instanceof Array) { config.entry = { main: config.entry, vendors: ["react", "react-dom", "react-router-dom", "react-router"] } } else if (config.entry && typeof config.entry === 'object') { config.entry.vendors = ["react", "react-loadable","react-dom", "react-router-dom","react-router"]; } Object.assign(splitChunksConfig, { cacheGroups: { vendors: { test: "vendors", name: 'vendors', priority:10, }, common: { name: 'common', minChunks: 2, minSize: 30000, chunks: 'all' }, styles: { name: 'styles', test: /\.css$/, chunks: 'all', priority: 9, enforce: true } } }) config.plugins.push(...[ new StatsWriterPlugin({ fields: null, transform: (data) => { let endTime = Date.now() data = { Time: (endTime - startTime)/1000 + 's' } return JSON.stringify(data, null, 2); } }), new BundleAnalyzerPlugin() ]) } return config }
以上實際打包運行大約35S左右，實際打包后的模塊一共2.41M，打包后生成的分析圖發現Ant Design有個圖標庫特別大，大約有520kb，但是實際項目中用到的圖標特別少。到此不想繼續折騰React腳手架了，還不如重新配置一套Webpack替換腳手架。
5、總結
-
React腳手架配置過重，對於龐大的后台系統不實用 -
Ant Design的圖標庫沒有按需加載的功能 -
修改
React腳手架配置太麻煩
自定義
Webpack配置實踐
1、結果：
2、優化點：
-
利用
autodll-webpack-plugin插件，生產環境通過預編譯的手段將AntReact等穩定的模塊全部先抽離出來，只打包編譯業務代碼。 -
babel-loader開啟緩存 -
利用
happypack加快編譯速度 -
生產環境不開啟
devtool -
細化分包
-
針對項目輕量級配置（后台項目，基本只在 Chrome 瀏覽器下使用）
問題：
-
抽離出來的第三方模塊大概有3M多，經過
zip大概也有800多Kb,首屏加載比較慢。如果結合externals屬性將這些靜態資源放置到CDN上或許加載會更快。
3、基礎配置：
1、安裝babel模塊，使用的是babel7.0版本。
npm i install babel-loader @babel/core @babel/preset-env @babel/preset-react @babel/preset-typescript @babel/plugin-transform-runtime --save-dev npm i @babel/runtime-corejs3 --save
在更目錄下創建babel.config.js babel的配置文件
module.exports = function (api) { api.cache(true); const presets = ["@babel/env","@babel/preset-react","@babel/preset-typescript"]; const plugins = [ ["@babel/plugin-transform-runtime", { corejs: 3, }], "@babel/plugin-syntax-dynamic-import", "@babel/plugin-proposal-class-properties", ]; if (process.env.NODE_ENVN !== "production") { plugins.push(["import", { "libraryName": "antd", // 引入庫名稱 "libraryDirectory": "es", // 來源,default: lib "style": "css" // 全部,or 按需'css' }]); } return { presets, plugins }; }
2、babel-loader配置：
const os = require('os');
const HappyPack = require('happypack');
const happyThreadPool = HappyPack.ThreadPool({ size: os.cpus().length });
module.exports = {
.....
module: {
rules: [
{
test: /\.(ts|tsx|js|jsx)$/,
exclude: /node_modules/,
loaders: ['happypack/loader?id=babel']
}
},
plugins: [
new HappyPack({
id: 'babel',
threadPool: happyThreadPool,
loaders: [{
loader:'babel-loader',
options: {
cacheDirectory: true
}
}]
})
]
}
3、mini-css-extract-plugin 插件打包抽離CSS到單獨的文件
var MiniCssExtractPlugin = require('mini-css-extract-plugin'); var NODE_ENV = process.env.NODE_ENV var devMode = NODE_ENV !== 'production'; var utils = require('./utils') module.exports = { .... module: { rules: [ { test: /\.css$/, use: [ { loader: devMode ? 'style-loader' : MiniCssExtractPlugin.loader, options: { // only enable hot in development hmr: devMode, // if hmr does not work, this is a forceful method. reloadAll: true, }, }, "css-loader" ], }, ] }, plugins: [ new MiniCssExtractPlugin({ //utils.assetsPath 打包后存放的地址 filename: devMode ? '[name].css' : utils.assetsPath('css/[name].[chunkhash].css'), chunkFilename: devMode ? '[name].css' : utils.assetsPath('css/[name].[chunkhash].css'), ignoreOrder: false, // Enable to remove warnings about conflicting order }) ] }
4、html-webpack-plugin 生成html 文件
const HtmlWebpackPlugin = require('html-webpack-plugin')
var htmlTplPath = path.join(__dirname, '../public/')
module.exports = {
....
plugins: [
new HtmlWebpackPlugin({
filename: 'index.html',
template: htmlTplPath + 'index.html',
inject: true,
})
]
}
5、webpack.DefinePlugin生成業務代碼可以獲取的變量，可以區分環境
const webpack = require('webpack')
module.exports = {
....
plugins: [
new webpack.DefinePlugin({
'process.env.NODE_ENV': JSON.stringify(devMode ? 'development' : 'production'),
'perfixerURL': JSON.stringify('//yzadmin.111.com.cn')
}),
}
4、開發環境配置：
放於webpack.development.config.js文件
var path = require('path'); var webpack = require('webpack'); var merge = require('webpack-merge'); var FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin') var entryScriptPath = path.join(__dirname, '../src/') var base = require('./webpack.base.config'); module.exports = merge(base, { entry: { app: [entryScriptPath+'index'] // Your appʼs entry point }, output: { path: path.join(__dirname, '../dist/'), filename: '[name].js', chunkFilename: '[name].[chunkhash].js' }, module: { }, plugins: [ new webpack.ContextReplacementPlugin(/moment[\/\\]locale$/, /zh-cn/), new webpack.HotModuleReplacementPlugin(), new FriendlyErrorsPlugin(), ] });
start.js文件,用於npm start啟動本地服務
var webpack = require('webpack'); var opn = require('opn') var WebpackDevServer = require('webpack-dev-server'); var config = require('./webpack.development.config'); config.entry.app.unshift("webpack-dev-server/client?http://127.0.0.1:9000/", "webpack/hot/dev-server"); new WebpackDevServer(webpack(config), { publicPath: config.output.publicPath, hot: true, historyApiFallback: { index: '/public' } }).listen(9000, '127.0.0.1', function (err, result) { if (err) { return console.log(err); } opn('http://127.0.0.1:9000/') });
5、生產環境配置：
放於webpack.production.config.js文件
const path = require('path')
const merge = require('webpack-merge')
const baseWebpackConfig = require('./webpack.base.config');
const config = require('./webpack.env.config')
const utils = require('./utils')
const AutoDllPlugin = require('autodll-webpack-plugin');
const TerserJSPlugin = require('terser-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
function resolve(dir) {
return path.join(__dirname, '..', dir)
}
const webpackConfig = merge(baseWebpackConfig, {
module: {
},
devtool: config.build.productionSourceMap ? '#source-map' : false,
entry: {
app: resolve('src/index'),
},
output: {
path: config.build.assetsRoot,
filename: utils.assetsPath('js/[name].[chunkhash].js'),
chunkFilename: utils.assetsPath('js/[name].[chunkhash].js')
},
optimization: {
minimizer: [new TerserJSPlugin({}), new OptimizeCSSAssetsPlugin({})],
splitChunks: {
cacheGroups: {
common: {
test: /[\\/]src[\\/]/,
name: 'common',
chunks: 'all',
priority: 2,
minChunks: 2,
},
// 分離css到一個css文件
styles: {
name: 'styles',
test: /\.css$/,
chunks: 'all',
priority: 9,
enforce: true,
}
}
},
runtimeChunk: {
name:"manifest"
}
},
plugins: [
new AutoDllPlugin({
inject: true, // will inject the DLL bundles to index.html
filename: '[name].dll.js',
path: './dll',
entry: {
// 第三方庫
react: ["react","react-dom","react-router", "react-router-dom",'react-loadable'],
antd: ['antd/es'],
untils: ['qs','qrcode'],
plugins:['braft-editor','js-export-excel']
}
})
]
})
if (config.build.productionGzip) {
const CompressionWebpackPlugin = require('compression-webpack-plugin')
webpackConfig.plugins.push(
new CompressionWebpackPlugin({
filename: '[path].gz[query]',
algorithm: 'gzip',
test: new RegExp(
'\\.(' +
config.build.productionGzipExtensions.join('|') +
')$'
),
threshold: 10240,
minRatio: 0.8
})
)
}
if (config.build.bundleAnalyzerReport) {
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}
module.exports = webpackConfig
build.js 用於npm run build
process.env.NODE_ENV = 'production' var ora = require('ora') var path = require('path') var chalk = require('chalk') var shell = require('shelljs') var webpack = require('webpack') var config = require('./webpack.env.config') var webpackConfig = require('./webpack.production.config') var spinner = ora('building for production...') spinner.start() var assetsPath = path.join(config.build.assetsRoot, config.build.assetsSubDirectory) shell.config.silent = true shell.rm('-rf', assetsPath) shell.mkdir('-p', assetsPath) shell.cp('-R', 'static/*', assetsPath) shell.config.silent = false webpack(webpackConfig, function (err, stats) { spinner.stop() if (err) throw err process.stdout.write(stats.toString({ 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' )) })
修改package.json
"scripts": { "start": "node webpack/start.js", "build": "node webpack/build.js" },
6、總結
-
通過本次實踐大致對
Webpack有了初步了解，但關於Webpack的內部原理沒有仔細探究過 -
對一些腳手架做配置修改的前提是需要了解
Webpack基礎內容 -
優化一個項目首先需要知道是大致什么原因造成的，可以利用的工具有
speed-measure-webpack-plugin,webpack-bundle-analyzer等 -
項目雖然加入了
typeScript但並沒有很好的利用