1. 初始化react app

   npx create-react-app multiple-page-app
   

2. eject(eject前要commit)

   yarn eject
   

3. 在src文件夹里新建一个about.css(假如我们要做的另一个页面是about.html)

   body{
       background-color: yellow;
   }
   

4. 在src文件夹里新建一个about.js

   import React from 'react';
   import ReactDOM from 'react-dom';
   import './about.css';
   ReactDOM.render(<div>about</div>, document.getElementById('root'));
   

5. 增加入口配置，config/webpack.config.dev.js

   entry: {
       index:[
           require.resolve('./polyfills'),
           require.resolve('react-dev-utils/webpackHotDevClient'),
           paths.appIndexJs
       ],
       about: [
           require.resolve('./polyfills'),
           require.resolve('react-dev-utils/webpackHotDevClient'),
           paths.appSrc + "/about.js",
       ]
   },
   

6. 修改输出配置output选项

   filename: 'static/js/[name].bundle.js',
   

7. 增加HtmlWebpackPlugin

   new HtmlWebpackPlugin({
       inject: true,
       chunks: ["index"],
       template: paths.appHtml,
   }),
   new HtmlWebpackPlugin({
       inject: true,
       chunks: ["about"],
       template: paths.appHtml,
       filename: 'about.html',
   }),
   

8. 效果如下
   

9. 然后按照对dev.js的修改，同样修改好prod.js，就可以build出两个页面了。

完整代码可以在github上看到：
https://github.com/shengoo/react-demo/tree/master/multiple-page-app