webpack 解决app.js文件过大问题（初始化）

引入压缩插件，分别对 Js、Html、Css 进行压缩，Js压缩：UglifyJsPlugin，Html压缩HtmlWebpackPlugin，提取公共资源：CommonsChunkPlugin，提取css并压缩：ExtractTextPlugin 。

配置全局变量
告诉 webpack 我要发布 production 了,按照 production 方式去打包。

   new webpack.DefinePlugin({
        'process.env': {
            //注意一个单引号一个双引号…… 这里是要将 "production" 替换到文件里面
            NODE_ENV: '"production"'
        }
    })

注意 devtool 中的 source-map。

可以试一下,当开启 devtool打包后的文件

devtool: "inline-source-map"

ExtractTextPlugin提取css并压缩

使 css 剥离 js 文件, 将 css 单独打包。
依赖插件 npm install --save-dev extract-text-webpack-plugin 先安装再使用

    var ExtractTextPlugin = require('extract-text-webpack-plugin');
    
    //在 plugins 中配置
    plugins: [ new ExtractTextPlugin('[name].[contenthash].css') ]
把 css 单独打包出来，免得以后只修改 css 导致 浏览器端 js 的缓存也失效了。
这里使用了 contenthash, webpack 会按照内容去生成 hash 值。

压缩, 去除注释

    //在 plugins 中添加
    new webpack.optimize.UglifyJsPlugin({
        comments: false,        //去掉注释
        compress: {
            warnings: false    //忽略警告,要不然会有一大堆的黄色字体出现……
        }
    })

开启 gzip 压缩

    var CompressionWebpackPlugin = require('compression-webpack-plugin');

    //在 plugin 中添加
    new CompressionWebpackPlugin({ //gzip 压缩
        asset: '[path].gz[query]',
        algorithm: 'gzip',
        test: new RegExp(
            '\\.(js|css)$'    //压缩 js 与 css
        ),
        threshold: 10240,
        minRatio: 0.8
    })

压缩 html, 自动添加上面生成的静态资源。

    var HtmlWebpackPlugin = require('html-webpack-plugin');
    
    new HtmlWebpackPlugin({
        filename: 'react.html',    //生成的文件，从 output.path 开始 output.path + "/react.html"
        template: '../client/react.html',  //读取的模板文件,这个路径是相对于当前这个配置文件的
        inject: true, // 自动注入
        minify: {
            removeComments: true,        //去注释
            collapseWhitespace: true,    //压缩空格
            removeAttributeQuotes: true  //去除属性引用
            // more options:
            // https://github.com/kangax/html-minifier#options-quick-reference
        },
        //必须通过上面的 CommonsChunkPlugin 的依赖关系自动添加 js，css 等
        chunksSortMode: 'dependency'
    })

项目中的配置

 // 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,
    }),
    // 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: process.env.NODE_ENV === 'testing'
        ? 'index.html'
        : 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'
    }),
    // new BundleAnalyzerPlugin(),
    // keep modules.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 modules 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: ['.*']
      }
    ])