javascript - 为什么 webpack4 生产包总是包含 style-loader、css-loader 和 vue-loader 内容？

Question

我在 webpack 中使用生产模式构建的多入口点最终 bundle 中导出的多入口编译 js 文件始终包含加载器内容。如何消除它们以及为什么包含它们？

重现

git clone https://github.com/adamchenwei/boilerplate-webpack-babel-sass-storybook-vuejs.git
git checkout step/3-prod-webpack-build-setup-basic
npm install
npm run build:prod

任何想法将不胜感激。 https://webpack.js.org/plugins/module-concatenation-plugin/也没有帮助。 我读了几个 SO 似乎还没有解决方案。

谢谢

webpack.common.js

const path = require('path');
const CleanWebpackPlugin = require('clean-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');

function resolve (dir) {
  return path.join(__dirname, '..', dir)
}
module.exports = {
  entry: {
    app: './src/library.js',
    HelloComp: './src/components/HelloComponent/HelloComponent.vue',
    Bye: './src/components/ByeComponent/ByeComponent.vue'
  },
  plugins: [
    new CleanWebpackPlugin(['dist']),
    new HtmlWebpackPlugin({
      title: 'Production'
    })
  ],
  output: {
    filename: '[name].js',
    path: path.resolve(__dirname, 'dist')
  },
  externals: {
    'vue': {
      root: 'vue',
      commonjs2: 'vue',
      commonjs: 'vue',
      amd: 'vue',
      umd: 'vue'
    },
    'vue-router': {
      root: 'vue-router',
      commonjs2: 'vue-router',
      commonjs: 'vue-router',
      amd: 'vue-router',
      umd: 'vue-router'
    },
    'style-loader': {
      root: 'style-loader',
      commonjs2: 'style-loader',
      commonjs: 'style-loader',
      amd: 'style-loader',
      umd: 'style-loader'
    },
    'vue-hot-reload-api': {
      root: 'vue-hot-reload-api',
      commonjs2: 'vue-hot-reload-api',
      commonjs: 'vue-hot-reload-api',
      amd: 'vue-hot-reload-api',
      umd: 'vue-hot-reload-api'
    },
    'vue-loader': {
      root: 'vue-loader',
      commonjs2: 'vue-loader',
      commonjs: 'vue-loader',
      amd: 'vue-loader',
      umd: 'vue-loader'
    }
  }
}

webpack.prod.js

const merge = require('webpack-merge');
const common = require('./webpack.common.js');
const webpack = require('webpack')
const { VueLoaderPlugin } = require('vue-loader')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const CopyWebpackPlugin = require('copy-webpack-plugin')
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
// const path = require('path')
// function resolve (dir) {
//   return path.join(__dirname, '..', dir)
// }

const configedAnalyzer = new BundleAnalyzerPlugin({
  // Can be `server`, `static` or `disabled`.
  // In `server` mode analyzer will start HTTP server to show bundle report.
  // In `static` mode single HTML file with bundle report will be generated.
  // In `disabled` mode you can use this plugin to just generate Webpack Stats JSON file by setting `generateStatsFile` to `true`.
  analyzerMode: 'static',
  // Host that will be used in `server` mode to start HTTP server.
  analyzerHost: '127.0.0.1',
  // Port that will be used in `server` mode to start HTTP server.
  analyzerPort: 8887,
  // Path to bundle report file that will be generated in `static` mode.
  // Relative to bundles output directory.
  reportFilename: './../report/bundle_anlaysis.html',
  // Module sizes to show in report by default.
  // Should be one of `stat`, `parsed` or `gzip`.
  // See "Definitions" section for more information.
  defaultSizes: 'gzip',
  // Automatically open report in default browser
  openAnalyzer: true,
  // If `true`, Webpack Stats JSON file will be generated in bundles output directory
  generateStatsFile: true,
  // Name of Webpack Stats JSON file that will be generated if `generateStatsFile` is `true`.
  // Relative to bundles output directory.
  statsFilename: 'stats.json',
  // Options for `stats.toJson()` method.
  // For example you can exclude sources of your modules
  // from stats file with `source: false` option.
  // See more options here: https://github.com/webpack/webpack/blob/webpack-1/lib/Stats.js#L21
  statsOptions: null,
  // Log level. Can be 'info', 'warn', 'error' or 'silent'.
  logLevel: 'info'
})

module.exports = merge(common, {
  mode: 'production',
  module: {
    rules: [
      {
        test: /\.vue$/,
        use: 'vue-loader'
      },
      // IMPORTANT: All js load should come AFTER vue-loader!!!
      {
        test: /\.(js|vue)$/,
        use: 'eslint-loader',
        enforce: 'pre' // kick in before other loader... Q: also before vue-loader I suppose? maybe better move it to top?
      },
      {
        test: /\.css$/,
        use: [
          'vue-style-loader',
          'css-loader'
        ]
      },
      {
        test: /\.scss$/,
        use: [
          'style-loader', // creates style nodes from JS strings
          'css-loader', // translates CSS into CommonJS
          'sass-loader' // compiles Sass to CSS, using Node Sass by default
        ]
      },
      {
        test: /\.js$/,
        use: 'babel-loader'
      }
    ]
  },
  plugins: [
    new webpack.HotModuleReplacementPlugin(),
    new VueLoaderPlugin(),
    new HtmlWebpackPlugin({
      filename: 'index.html',
      template: 'index.html',
      inject: true
    }),
    new CopyWebpackPlugin([{
      // NOTE: it does not really do anything, unless we have a asset folder, that needed no compression
      from: './static/',
      to: './static/',
      toType: 'dir'
    }]),

    // NOTE: honestly, this did not help reduce prod bundle size... but for wtw:
    // https://webpack.js.org/plugins/module-concatenation-plugin/
    new webpack.optimize.ModuleConcatenationPlugin(),

    // NOTE: disable when needed, its just to analyze code
    configedAnalyzer
  ],
  stats: {
    // Examine all modules
    maxModules: Infinity,
    // Display bailout reasons
    optimizationBailout: true
  }
});

Answer 1

从你的外部移除 style-loader 并确保从你的 css 生成实际的 css 文件...否则 webpack 必须以某种方式插入你的样式，对吗？

为此使用 mini-css-extract-plugin .

 {
        test: /\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          'css-loader'
        ]
      },
      {
        test: /\.scss$/,
        use: [
          MiniCssExtractPlugin.loader,
          'css-loader', // translates CSS into CommonJS
          'sass-loader' // compiles Sass to CSS, using Node Sass by default
        ]
    }

不要忘记将 new MiniCssExtractPlugin() 添加到您的插件中。仅适用于生产构建。