遇见的问题TypeError: Cannot read property ‘tap’ of undefined

先看项目目录结构 ：关于项目的修改及改造 再项目完事的时候会发布的

如果你也遇见这个问题的话 这一篇博客应该完全可以解决
问题描述：

building for sit environment...D:\EVDownload\adminMPA\node_modules\script-ext-html-webpack-plugin\lib\plugin.js:50
      compilation.hooks.htmlWebpackPluginAlterAssetTags.tap(PLUGIN, alterAssetTags);
                                                        ^

TypeError: Cannot read property 'tap' of undefined
    at ScriptExtHtmlWebpackPlugin.compilationCallback (D:\EVDownload\adminMPA\node_modules\script-ext-html-webpack-plugin\lib\plugin.js:50:57)
    at SyncHook.eval [as call] (eval at create (D:\EVDownload\adminMPA\node_modules\tapable\lib\HookCodeFactory.js:19:10), <anonymous>:11:1)
    at SyncHook.lazyCompileHook (D:\EVDownload\adminMPA\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.newCompilation (D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:504:26)
    at D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:540:29
    at AsyncSeriesHook.eval [as callAsync] (eval at create (D:\EVDownload\adminMPA\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:6:1)
    at AsyncSeriesHook.lazyCompileHook (D:\EVDownload\adminMPA\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.compile (D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:535:28)
    at D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:274:11
    at Compiler.readRecords (D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:402:11)
    at D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:271:10
    at AsyncSeriesHook.eval [as callAsync] (eval at create (D:\EVDownload\adminMPA\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:6:1)
    at AsyncSeriesHook.lazyCompileHook (D:\EVDownload\adminMPA\node_modules\tapable\lib\Hook.js:154:20)
    at D:\EVDownload\adminMPA\node_modules\webpack\lib\Compiler.js:268:19
    at AsyncSeriesHook.eval [as callAsync] (eval at create (D:\EVDownload\adminMPA\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:15:1)
    at AsyncSeriesHook.lazyCompileHook (D:\EVDownload\adminMPA\node_modules\tapable\lib\Hook.js:154:20)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! admin@1.0.0 build:sit: `cross-env NODE_ENV=production env_config=sit node build/build.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the admin@1.0.0 build:sit 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\l\AppData\Roaming\npm-cache\_logs\2020-11-10T02_45_03_911Z-debug.log

这个问题全网只有两个人写过博客 但是不适合我这个 （我也不知道为啥 ）
如果你也有这样的问题可以尝试下：
第一篇博客解决办法发是 webpack 和 webpackServe 及 html-webpack-plugin 版本冲突 这个直接去重写install 个版本就好了
博客链接 ： https://blog.csdn.net/qq_31290307/article/details/86158770
第二篇博客解决办法如下 ：
set “html-webpack-plugin”: “^4.0.0-alpha” => “4.0.0-alpha”
remove node_modules
remove package-lock.json
npm install
博客链接： https://www.cnblogs.com/ybz94/p/9625864.html

以上两篇博客如果还不能解决你的问题 那你就跟着我走吧！ 以下是我的解决思路
第一点 ： 检查入口文件 是不是有多余的东西
打印结果如下 ：

对比图

在这里我们发现入口文件 多了几个js 分别是 errorLog.js 和 permission.js
所以我们要做的操作是 将多余的js删除
入口函数写法如下

//多入口配置
// 通过glob模块读取views文件夹下的所有对应文件夹下的js后缀文件，如果该文件存在
// 那么就作为入口处理
exports.entries = function() { 
  var entryFiles = glob.sync(PAGE_PATH + '*.html')
  let arr = []
  entryHtml.forEach((filePath) => { 
      let filename = filePath.substring(filePath.lastIndexOf('\/') + 1, filePath.lastIndexOf('.'))
      let conf = { 
          // 模板来源
          template: filePath,
          // 文件名称
          filename: filename + '.html',
          // 页面模板需要加对应的js脚本，如果不加这行则每个页面都会引入所有的js脚本
          chunks: ['manifest', 'vendor', filename],
          inject: true,
          templateParameters: { 
                BASE_URL: config.build.assetsPublicPath + config.build.assetsSubDirectory,
              },
      }
      if (process.env.NODE_ENV === 'production') { 
          conf = merge(conf, { 
              minify: { 
                  removeComments: true,
                  collapseWhitespace: true,
                  removeAttributeQuotes: true
              },
              chunksSortMode: 'dependency'
          })
      }
      arr.push(new HtmlWebpackPlugin(conf))
  })
  console.log(arr , 'arr')
  return arr
}

我们看下打印的数据对不对

[
  HtmlWebpackPlugin { 
    options: { 
      template: 'D:/EVDownload/adminMPA/src/views/index/index.html',
      templateContent: false,
      templateParameters: [Object],
      filename: 'index.html',
      hash: false,
      inject: true,
      compile: true,
      favicon: false,
      minify: false,
      cache: true,
      showErrors: true,
      chunks: [Array],
      excludeChunks: [],
      chunksSortMode: 'auto',
      meta: { },
      title: 'Webpack App',
      xhtml: false
    },
    childCompilerHash: undefined,
    childCompilationOutputName: undefined,
    assetJson: undefined,
    hash: undefined,
    version: 4
  },
  HtmlWebpackPlugin { 
    options: { 
      template: 'D:/EVDownload/adminMPA/src/views/page/page.html',
      templateContent: false,
      templateParameters: [Object],
      filename: 'page.html',
      hash: false,
      inject: true,
      compile: true,
      favicon: false,
      minify: false,
      cache: true,
      showErrors: true,
      chunks: [Array],
      excludeChunks: [],
      chunksSortMode: 'auto',
      meta: { },
      title: 'Webpack App',
      xhtml: false
    },
    childCompilerHash: undefined,
    childCompilationOutputName: undefined,
    assetJson: undefined,
    hash: undefined,
    version: 4
  },
  HtmlWebpackPlugin { 
    options: { 
      template: 'D:/EVDownload/adminMPA/src/views/pagetwo/pagetwo.html',
      templateContent: false,
      templateParameters: [Object],
      filename: 'pagetwo.html',
      hash: false,
      inject: true,
      compile: true,
      favicon: false,
      minify: false,
      cache: true,
      showErrors: true,
      chunks: [Array],
      excludeChunks: [],
      chunksSortMode: 'auto',
      meta: { },
      title: 'Webpack App',
      xhtml: false
    },
    childCompilerHash: undefined,
    childCompilationOutputName: undefined,
    assetJson: undefined,
    hash: undefined,
    version: 4
  }
]

仔细瞅了一下 ， 也没有大问题 ，但是当我打开config文件时 发现我在这里竟然也设置了build路径 【奔溃】，那么再重新修改下打包路径吧 。
第一步在 webpack.dev.conf.js 里修改

 plugins: [
    new webpack.DefinePlugin({ 
      'process.env': require('../config/dev.env')
    }),
    new webpack.HotModuleReplacementPlugin(),
    

    new htmlWebpackPlugin({ 
      filename : 'index.html',//输出的html路径
      template : 'index.html', //html模板路径
      //inject : 'head', //js文件在head中，若为body则在body中
      inject : true,
      title : 'index',
      chunks : ['app'], //打包时只打包main和a的js文件，见entry，注意使用chunks时模板index.html文件里面不允许有script标签，即使注释掉也会报错
      templateParameters: { 
        BASE_URL: config.dev.assetsPublicPath + config.dev.assetsSubDirectory
      }
    }),
    
  new htmlWebpackPlugin({ 
    filename : 'page.html',//输出的html路径
    template : 'page.html', //html模板路径
    //inject : 'head', //js文件在head中，若为body则在body中
    inject : true,
    title : 'page',
    chunks : ['page'], //打包时只打包main和a的js文件，见entry，注意使用chunks时模板index.html文件里面不允许有script标签，即使注释掉也会报错
    templateParameters: { 
      BASE_URL: config.dev.assetsPublicPath + config.dev.assetsSubDirectory
    }
  }),
  new htmlWebpackPlugin({ 
    filename : 'pagetwo.html',//输出的html路径
    template : 'pagetwo.html', //html模板路径
    //inject : 'head', //js文件在head中，若为body则在body中
    inject : true,
    title : 'pagetwo',
    chunks : ['pagetwo'], //打包时只打包main和a的js文件，见entry，注意使用chunks时模板index.html文件里面不允许有script标签，即使注释掉也会报错
    templateParameters: { 
      BASE_URL: config.dev.assetsPublicPath + config.dev.assetsSubDirectory
    }
  }),
  

    new webpack.NamedModulesPlugin(), // HMR shows correct file names in console on update.
    new webpack.NoEmitOnErrorsPlugin(),
    new CopyWebpackPlugin([
      { 
        from: path.resolve(__dirname, '../static'),
        to: config.dev.assetsSubDirectory,
        ignore: ['.*']
      }
    ])
   
  ]
})

因为我这有三个动态项目 目前插如三个 new htmlWebpackPlugin

在webpack.prod.conf.js 里修改如下

 plugins: [
    // http://vuejs.github.io/vue-loader/en/workflow/production.html
    new webpack.DefinePlugin({ 
      'process.env': env
    }),
    // extract css into its own file
    new MiniCssExtractPlugin({ 
      filename: utils.assetsPath('css/[name].[contenthash:8].css'),
      chunkFilename: utils.assetsPath('css/[name].[contenthash:8].css')
    }),
    
    new HtmlWebpackPlugin({ 
      filename: config.build.app,
      template: 'index.html',
      inject: true,
      favicon: resolve('favicon.ico'),
      title: 'index',
      templateParameters: { 
        BASE_URL: config.build.assetsPublicPath + config.build.assetsSubDirectory
      },
      chunks: ['manifest', 'vendor', 'app'],
      minify: { 
        removeComments: true,
        collapseWhitespace: true,
        removeAttributeQuotes: true
        // more options:
        // https://github.com/kangax/html-minifier#options-quick-reference
      }
      // default sort mode uses toposort which cannot handle cyclic deps
      // in certain cases, and in webpack 4, chunk order in HTML doesn't
      // matter anyway

    }),
    new HtmlWebpackPlugin({ 
      filename: config.build.page,
      template: 'page.html',
      inject: true,
      favicon: resolve('favicon.ico'),
      title: 'page',
      templateParameters: { 
        BASE_URL: config.build.assetsPublicPath + config.build.assetsSubDirectory
      },
      chunks: ['manifest', 'vendor', 'page'],
      minify: { 
        removeComments: true,
        collapseWhitespace: true,
        removeAttributeQuotes: true
        // more options:
        // https://github.com/kangax/html-minifier#options-quick-reference
      }
      // default sort mode uses toposort which cannot handle cyclic deps
      // in certain cases, and in webpack 4, chunk order in HTML doesn't
      // matter anyway

    }),
    new HtmlWebpackPlugin({ 
      filename: config.build.pagetwo,
      template: 'pagetwo.html',
      inject: true,
      favicon: resolve('favicon.ico'),
      title: 'pagetwo',
      templateParameters: { 
        BASE_URL: config.build.assetsPublicPath + config.build.assetsSubDirectory
      },
      chunks: ['manifest', 'vendor', 'pagetwo'],
      minify: { 
        removeComments: true,
        collapseWhitespace: true,
        removeAttributeQuotes: true
        // more options:
        // https://github.com/kangax/html-minifier#options-quick-reference
      }
      // default sort mode uses toposort which cannot handle cyclic deps
      // in certain cases, and in webpack 4, chunk order in HTML doesn't
      // matter anyway

    }),
      
    new ScriptExtHtmlWebpackPlugin({ 
      //`runtime` must same as runtimeChunk name. default is `runtime`
      inline: /runtime\..*\.js$/
    }),
    // keep chunk.id stable when chunk has no name
    new webpack.NamedChunksPlugin(chunk => { 
      if (chunk.name) { 
        return chunk.name
      }
      const modules = Array.from(chunk.modulesIterable)
      if (modules.length > 1) { 
        const hash = require('hash-sum')
        const joinedHash = hash(modules.map(m => m.id).join('_'))
        let len = nameLength
        while (seen.has(joinedHash.substr(0, len))) len++
        seen.add(joinedHash.substr(0, len))
        return `chunk-${ joinedHash.substr(0, len)}`
      } else { 
        return modules[0].id
      }
    }),
    // keep module.id stable when vender modules does not change
    new webpack.HashedModuleIdsPlugin(),
    // copy custom static assets
    new CopyWebpackPlugin([
      { 
        from: path.resolve(__dirname, '../static'),
        to: config.build.assetsSubDirectory,
        ignore: ['.*']
      }
    ])
  ] ,

在这里也插入代码 （注释里有标记哦！！！！！！！！！！！）
好了 现在在运行下吧 看看效果咋样呢？

打包完成 成功啦 ！

小记
这个bug 说白了 问题的根点在出口文件这 ， 为什么会在这呢 ? 相关文档有说 是因为 webpack 新增 hook 属性 造成的看的我迷迷糊糊的 没明白 大致就是说你的出口文件应该怎么设置啥的。 哎！脑壳疼
为什么出口文件不能放在公共的utils 里呢 ？ 目前这样打包问题虽然解决但是 每次的修改过于复杂 （脑壳疼）， 如果有大神的话感谢指导下哈！！！后期我会把这个项目开源 详细请到个人中心查看
再此特别鸣谢 @璠哥 （一个温文尔雅的漂亮妹子） @劲琪 （一个阳光帅气的小帅哥）