使用WebPack CommonsChunkPlugin

Question

我使用 WebPack CommonsChunkPlugin 来提取重复代码并减少JavaScript代码大小。我有两个html页面和两个条目。我还添加了 ReactJs 供应商条目。到目前为止，在 webpack.config.js 中我们有：

var path = require("path");
var webpack = require('webpack');
var BundleTracker = require('webpack-bundle-tracker');
var BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;

module.exports = {
    context: __dirname,
    entry: {
        react: ["react", "react-dom"],
        home: './assets/js/home.jsx',
        about: './assets/js/about.jsx',
    },

    output: {
        path: path.resolve('./assets/bundles/'),
        filename: "[name].js",
    },

    plugins: [
        new BundleTracker({filename: './webpack-stats.json'}),

        new webpack.optimize.CommonsChunkPlugin({
            name: 'react',
            minChunks: Infinity
        }),

        new BundleAnalyzerPlugin(),
    ],

    module: {
        rules: [
            {
              test: /\.jsx?$/, 
              exclude: /node_modules/,
              loader: 'babel-loader',
              options: { 
                  plugins: [["lodash", { "id": ["semantic-ui-react"] }]],
                  presets: ["es2015", "react"]
              }  
            },
        ],
    },

    resolve: {
        modules: ['node_modules', 'bower_components'],
        extensions: ['*', '.js', '.jsx']
    },
};

此配置结果使用 webpack-bundle-analyzer ：

如您所见，有一些重复的代码，一些在红色区域，另一些在绿色区域。我想从家里提取这些js代码，并将捆绑包提取到一个单独的包中。要提取红色区域代码，即 lodash 库，我将这些行添加到webpack配置中：

new webpack.optimize.CommonsChunkPlugin({
    name: 'lodash',
    minChunks: function(module, count) {
        return module.context.indexOf('node_modules/lodash') >= 0;
    }
}), 

但是它没有按预期工作，并且lodash库代码仍然在home和bundle中，webpack也会创建一个名为lodash的包，它几乎是空的，不包含js库。

有关如何修复它的任何想法？如何提取绿色代码？

Answer 1

您的问题是您正在导入每个.js/.jsx文件中的第三方库，而不先将其导入公共文件（通常称为vendor.js）。
如果您有此文件导入所有依赖项并将其作为条目包含在 CommonsChunkPlugin 中，则webpack将不再包含您的最终包中的库（home.js和{{1} }）。该技术在webpack文档中称为代码拆分。

vendor.js （或适合您案件的名称）

about.js

<强> webpack.config.js

import 'react';
import 'react-dom';
import 'lodash';
import 'semantic-ui-react';
//... all your npm packages

<强>的index.html

var webpack = require('webpack');
var path = require('path');

module.exports = {
    context: __dirname,
    entry: {
        vendor: './assets/js/vendor.js,
        home: './assets/js/home.jsx',
        about: './assets/js/about.jsx',
    },
    output: {
        path: path.resolve('./assets/bundles/'),
        filename: '[name].js',
    },
    plugins: [
        new webpack.optimize.CommonsChunkPlugin({
            name: 'vendor',
            minChunks: Infinity
        }),
    ],

    //Rest of Your config ...
};

检查webpack代码拆分文档：

• 旧文档：https://webpack.github.io/docs/code-splitting.html#split-app-and-vendor-code
• 新文档：https://webpack.js.org/plugins/commons-chunk-plugin/#explicit-vendor-chunk

Answer 2

我设法通过向插件添加一个公共块来解决问题。所以最终的webpack配置是：

var path = require("path");
var webpack = require('webpack');
var BundleTracker = require('webpack-bundle-tracker');

module.exports = {

    context: __dirname,

    entry: {
        react: ["react", "react-dom"],
        home: './assets/js/home.jsx',
        about: './assets/js/about.jsx',
    },

    output: {
        path: path.resolve('./assets/bundles/'),
        filename: "[name].js",
    },

    plugins: [

        new BundleTracker({filename: './webpack-stats.json'}),

        new webpack.optimize.CommonsChunkPlugin({
            name: 'react',
            filename: '[name].js',
            minChunks: Infinity,
        }),

        new webpack.optimize.CommonsChunkPlugin({
            name: 'common',
            chunks: ['home', 'about'],
            filename: '[name].js',
        }),
    ],

    module: {
        rules: [
            {
                test: /\.jsx?$/, 
                exclude: /node_modules/,
                loader: 'babel-loader',
                options: { 
                    plugins: [
                      ["lodash", { "id": ["semantic-ui-react"] }]
                    ],
                    presets: ["es2015", "react"]
                }
            },
        ],
    },

    resolve: {
        modules: ['node_modules', 'bower_components'],
        extensions: ['*', '.js', '.jsx']
    },
};

现在捆绑分析仪输出如下：

如图所示，常见的语义 - ui-react和lodash库现在只是普通的捆绑而不再重复。