如果跟着webpack走，到清理 /dist 文件夹 这个部分。按照文档教程。

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

  module.exports = {
    entry: {
      app: './src/index.js',
      print: './src/print.js'
    },
    plugins: [
+     new CleanWebpackPlugin(['dist']),
      new HtmlWebpackPlugin({
        title: 'Output Management'
      })
    ],
    output: {
      filename: '[name].bundle.js',
      path: path.resolve(__dirname, 'dist')
    }
  };

这样如果是webpack4会报错，TypeError: CleanWebpackPlugin is not a constructor

原因是CleanWebpackPlugin写法更改，修改成如下即可。
参考：https://www.npmjs.com/package/clean-webpack-plugin

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

module.exports = {
    entry: {
        app: './src/index.js',
        print: './src/print.js'
    },
    plugins: [
    +   new CleanWebpackPlugin(),
        new HtmlWebpackPlugin({
            title: 'Output Management'
        })
    ],
    output: {
        filename: '[name].bundle.js',
        path: path.resolve(__dirname, 'dist')
    }

最后，关于中文文档的这部分问题，已经提交修改。
遇到webpack一些问题可以到
https://github.com/docschina/webpack.js.org/issues
这里查看