vue-cli搭建webpack4项目

先前开发了一个中大型的项目，修改下代码热更新30秒，项目启动4分钟，打包就更可怕了一打一上午。现在想通过webpack4好好优化一下，先弄个测试项目整整。

走起！初始化vue-cli项目

初始化的package.json文件

{
  "name": "create-dome-linwenjie",
  "version": "1.0.0",
  "description": "A Vue.js project",
  "author": "HandsomeLin <597167890@qq.com>",
  "private": true,
  "scripts": {
    "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
    "start": "npm run dev",
    "build": "node build/build.js"
  },
  "dependencies": {
    "vue": "^2.5.2"
  },
  "devDependencies": {
    "autoprefixer": "^7.1.2",
    "babel-core": "^6.22.1",
    "babel-helper-vue-jsx-merge-props": "^2.0.3",
    "babel-loader": "^7.1.1",
    "babel-plugin-syntax-jsx": "^6.18.0",
    "babel-plugin-transform-runtime": "^6.22.0",
    "babel-plugin-transform-vue-jsx": "^3.5.0",
    "babel-preset-env": "^1.3.2",
    "babel-preset-stage-2": "^6.22.0",
    "chalk": "^2.0.1",
    "copy-webpack-plugin": "^4.0.1",
    "css-loader": "^0.28.0",
    "extract-text-webpack-plugin": "^3.0.0",
    "file-loader": "^1.1.4",
    "friendly-errors-webpack-plugin": "^1.6.1",
    "html-webpack-plugin": "^2.30.1",
    "node-notifier": "^5.1.2",
    "optimize-css-assets-webpack-plugin": "^3.2.0",
    "ora": "^1.2.0",
    "portfinder": "^1.0.13",
    "postcss-import": "^11.0.0",
    "postcss-loader": "^2.0.8",
    "postcss-url": "^7.2.1",
    "rimraf": "^2.6.0",
    "semver": "^5.3.0",
    "shelljs": "^0.7.6",
    "uglifyjs-webpack-plugin": "^1.1.1",
    "url-loader": "^0.5.8",
    "vue-loader": "^13.3.0",
    "vue-style-loader": "^3.0.1",
    "vue-template-compiler": "^2.5.2",
    "webpack": "^3.6.0",
    "webpack-bundle-analyzer": "^2.9.0",
    "webpack-dev-server": "^2.9.1",
    "webpack-merge": "^4.1.0"
  },
  "engines": {
    "node": ">= 6.0.0",
    "npm": ">= 3.0.0"
  },
  "browserslist": [
    "> 1%",
    "last 2 versions",
    "not ie <= 8"
  ]
}

开始升级webpack4

修改package.json文件为下列版本，先删除原先版本(随后 npm i 下载新版本，接着npm run dev启动)：

    "webpack": "^4.5.0",
    "webpack-dev-server": "^3.1.4",

在package.json中添加 “webpack-cli”依赖 (随后 npm i 下载新版本，接着npm run dev启动)

    "webpack-cli":"^3.1.0",

修改package.json文件为下列版本，先删除原先版本(随后 npm i 下载新版本，接着npm run dev启动)：

    "html-webpack-plugin": "^3.2.0",

修改package.json文件为下列版本，先删除原先版本(随后 npm i 下载新版本，接着npm run dev启动)：

    "eslint-loader": "2.0.0",

修改package.json文件为下列版本，先删除原先版本(随后 npm i 下载新版本，接着npm run dev启动)：

  "vue-loader": "^15.3.0",

由于webpack4 版本依赖VueLoaderPlugin 插件，所以还需要去配置webpack.base.conf.js文件：

// 引入插件包
const VueLoaderPlugin = require('vue-loader/lib/plugin')
module.exports = {
 ....
 plugins: [
    new VueLoaderPlugin()
  ],
}

接着在为开发配置文件（webpack.dev.conf.js）和生产配置文件（webpack.prod.conf.js）分别配置mode属性：

  mode:'development',
  module: {
    ...
  },

  mode:'production',
  module: {
    ...
  },

继续npm run dev启动项目

由于在webpack4之后，不允许混用 exports和import。修改webpack.base.conf.js文件：

  {
     test: /\.js$/,
     loader: 'babel-loader',
     include: [resolve('src'), resolve('test')]
   },

到这里开发环境项目正常运行！接下来配置生产环境执行 npm run build 进行打包。

接下的配置应该是从V3升级到V4的代码修改过程中最为复杂的一部分。

1. 从webpack4开始官方移除了CommonsChunkPlugin插件，改用了optimization属性进行更加灵活的配置，所以要进行替换。
2. 将“extract-text-webpack-plugin” 使用“mini-css-extract-plugin” 替换，这两个插件是用来提取单独打包css文件，webpack4需要使用后者。（记得下载依赖 “mini-css-extract-plugin”: “^0.12.0”）

build/webpack.prod.conf.js文件：

'use strict'
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 MiniCssExtractPlugin = require('mini-css-extract-plugin') //webpack4 用该插件提取单独打包css文件 替代原来的 “extract-text-webpack-plugin”

const env = require('../config/prod.env')

const webpackConfig = merge(baseWebpackConfig, {
  mode: 'production',
  module: {
    rules: utils.styleLoaders({
      sourceMap: config.build.productionSourceMap,
      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')
  },
  // 使用该配置替代下面的CommonsChunkPlugin插件
  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: true 
      })
    ],
    splitChunks: {
      cacheGroups: {
        vendors: {
          test: /[\\/]node_modules[\\/]/,
          chunks: 'initial',
          name: 'vendors',
        },
        'async-vendors': {
          test: /[\\/]node_modules[\\/]/,
          minChunks: 2,
          chunks: 'async',
          name: 'async-vendors'
        }
      }
    },
    runtimeChunk: {
      name: 'runtime'
    }
  },
  plugins: [
    // http://vuejs.github.io/vue-loader/en/workflow/production.html
    new webpack.DefinePlugin({
      'process.env': env
    }),
    // new UglifyJsPlugin({
    //   uglifyOptions: {
    //     compress: {
    //       warnings: false
    //     }
    //   },
    //   sourceMap: config.build.productionSourceMap,
    //   parallel: true
    // }),
    // extract css into its own file
    // new ExtractTextPlugin({
    //   filename: utils.assetsPath('css/[name].[contenthash].css'),
    //   // Setting the following option to `false` will not extract CSS from codesplit chunks.
    //   // Their CSS will instead be inserted dynamically with style-loader when the codesplit chunk has been loaded by webpack.
    //   // It's currently set to `true` because we are seeing that sourcemaps are included in the codesplit bundle as well when it's `false`, 
    //   // increasing file size: https://github.com/vuejs-templates/webpack/issues/1110
    //   allChunks: true,
    // }),
    new MiniCssExtractPlugin({
      filename: utils.assetsPath('css/[name].[contenthash].css'),
      allChunks: true,
    }),
    // Compress extracted CSS. We are using this plugin so that possible
    // duplicated CSS from different components can be deduped.
    new OptimizeCSSPlugin({
      cssProcessorOptions: config.build.productionSourceMap ? {
        safe: true,
        map: {
          inline: false
        }
      } : {
        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
    new HtmlWebpackPlugin({
      filename: config.build.index,
      template: 'index.html',
      inject: true,
      minify: {
        removeComments: true,
        collapseWhitespace: true,
        removeAttributeQuotes: true
        // more options:
        // https://github.com/kangax/html-minifier#options-quick-reference
      },
      // necessary to consistently work with multiple chunks via CommonsChunkPlugin
      chunksSortMode: 'dependency'
    }),
    // keep module.id stable when vendor modules does not change
    new webpack.HashedModuleIdsPlugin(),
    // enable scope hoisting
    // new webpack.optimize.ModuleConcatenationPlugin(),
    // split vendor js into its own file
    // 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
    // }),
    // This instance extracts shared chunks from code splitted chunks and bundles them
    // in a separate chunk, similar to the vendor chunk
    // see: https://webpack.js.org/plugins/commons-chunk-plugin/#extra-async-commons-chunk
    // new webpack.optimize.CommonsChunkPlugin({
    //   name: 'app',
    //   async: 'vendor-async',
    //   children: true,
    //   minChunks: 3
    // }),

    // copy custom static assets
    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
    })
  )
}

if (config.build.bundleAnalyzerReport) {
  const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
  webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}
module.exports = webpackConfig

build/utils.js文件修改

'use strict'
const path = require('path')
const config = require('../config')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const packageConfig = require('../package.json')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')

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 || {}

  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',
        options: Object.assign({}, loaderOptions, {
          sourceMap: options.sourceMap
        })
      })
    }

    // Extract CSS when that option is specified
    // (which is the case during production build)
    // if (options.extract) {
    //   return ExtractTextPlugin.extract({
    //     use: loaders,
    //     fallback: 'vue-style-loader'
    //   })
    // } else {
    //   return ['vue-style-loader'].concat(loaders)
    // } 升级 webpack4， 由 ExtractTextPlugin 改用 MiniCssExtractPlugin
    return [
      options.extract ? MiniCssExtractPlugin.loader : 'vue-style-loader',
    ].concat(loaders)
  }

  // https://vue-loader.vuejs.org/en/configurations/extract-css.html
  return {
    css: generateLoaders(),
    postcss: generateLoaders(),
    less: generateLoaders('less'),
    sass: generateLoaders('sass', { indentedSyntax: true }),
    scss: generateLoaders('sass'),
    stylus: generateLoaders('stylus'),
    styl: generateLoaders('stylus')
  }

}

// Generate loaders for standalone style files (outside of .vue)
exports.styleLoaders = function (options) {
  const output = []
  const loaders = exports.cssLoaders(options)

  for (const extension in loaders) {
    const loader = loaders[extension]
    output.push({
      test: new RegExp('\\.' + extension + '$'),
      use: loader
    })
  }

  return output
}

exports.createNotifierCallback = () => {
  const notifier = require('node-notifier')

  return (severity, errors) => {
    if (severity !== 'error') return

    const error = errors[0]
    const filename = error.file && error.file.split('!').pop()

    notifier.notify({
      title: packageConfig.name,
      message: severity + ': ' + error.name,
      subtitle: filename || '',
      icon: path.join(__dirname, 'logo.png')
    })
  }
}

修改完之后对项目进行打包（npm run build）成功！

参考质料

升级指南

以上就是我对升级webpack4的理解,如果文章由于我学识浅薄,导致您发现有严重谬误的地方,请一定在评论中指出,我会在第一时间修正我的文章,以避免误人子弟。