老师，我的js里面使用contenthashbuild成功了
'use strict';

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


console.log(__dirname, 'dist');
console.log(path.join(__dirname, 'dist'));
// __dirname 当前目录 /remaineey/workspace/webpack
module.exports = {
    entry: './src/index.js', // 单入口
    entry: { // 多入口
        index: './src/index.js',
        search: './src/search.js',
    },
    output: {
        path: path.join(__dirname, 'dist'),
        filename: '[name][contenthash:8].js',
    },
    mode: 'development',
    module: {
        rules: [
            { test: /\.js$/, use: 'babel-loader' },
            {
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader',
                ]
            },
            {
                test: /\.less$/,
                use: [
                    'style-loader',
                    'css-loader',
                    'less-loader'
                ]
            },
            {
                test: /\.(jpeg|png|jpg)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            limit: 333330,
                        }
                    }
                ]
            }
        ]
    },
    // 默认是false，不开启
    // 参考： https://www.webpackjs.com/configuration/watch/
    // watch: true,
    // // 只有开启监听模式时，watch才有意义
    // watchOptions: {
    // // 不监听的文件或者文件目录，支持正则匹配
    // ignored: /node_modules/,
    // // 当第一个文件更改，会在重新构建前增加延迟。这个选项允许 webpack 将这段时间内进行的任何其他更改都聚合到一次重新构建里。以毫秒为单位
    // aggregateTimeout: 300,
    // // 通过传递 true 开启 polling，或者指定毫秒为单位进行轮询。
    // poll: 1000 // 每秒检查一次变动
    // },
    // 热替换影响了chunkhash的使用，你要确保hotModuleReplacementPlugin(）函数没在生产环境下执行
    // plugins: [
    // new webpack.HotModuleReplacementPlugin()
    // ],
    devServer: {
        contentBase: './dist',
        hot: true
    }
};

经过亲自实验，发现如果output name 设置为 [chunkhash:8] 就会报错

错误信息如下：

ERROR in chunk index [entry]
[name]_[chunkhash:8].js
Cannot use [chunkhash] or [contenthash] for chunk in '[name]_[chunkhash:8].js' (use [hash] instead)

ERROR in chunk search [entry]
[name]_[chunkhash:8].js
Cannot use [chunkhash] or [contenthash] for chunk in '[name]_[chunkhash:8].js' (use [hash] instead)

如果修改为 filename: '[name]_[hash:8].js' 正常，

所以

像图片，字体文件，css文件是不是应该是contenthash

js文件应该是 filename: '[name]_[hash:8].js'

老师这个报错是什么原因：
webpack-dev-server --config webpack.dev.js --open

i ｢wds｣: Project is running at http://localhost:8080/
i ｢wds｣: webpack output is served from /
i ｢wds｣: Content not from webpack is served from D:\A项目-project\demo\my-project\dist
events.js:174
      throw er; // Unhandled 'error' event
      ^

按照老师的写的，加入MiniCssExtractPlugin后报了这个错：
> my-project@1.0.0 build C:\Users\HP\Desktop\my-project
> webpack --config webpack.prod.js

Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
 - configuration has an unknown property 'plugin'. These properties are valid:
   object { amd?, bail?, cache?, context?, dependencies?, devServer?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions? }
   For typos: please correct them.
   For loader options: webpack >= v2.0.0 no longer allows custom properties in configuration.
     Loaders should be updated to allow passing options via loader options in module.rules.
     Until loaders are updated one can use the LoaderOptionsPlugin to pass these options to the loader:
     plugins: [
       new webpack.LoaderOptionsPlugin({
         // test: /\.xxx$/, // may apply this only for some modules
         options: {
           plugin: …
         }
       })
     ]
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! my-project@1.0.0 build: `webpack --config webpack.prod.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the my-project@1.0.0 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\HP\AppData\Roaming\npm-cache\_logs\2019-07-14T03_39_18_270Z-debug.log