Cannot find module ‘webpack‘ Require stack

一、Class extends value undefined is not a constructor or null

Building for production... ERROR  TypeError: Class extends value undefined is not a constructor or null
TypeError: Class extends value undefined is not a constructor or nullat Object.<anonymous> (D:\Users\IdeaProjects\node_modules\mini-css-extract-plugin\dist\CssDependency.js:12:46)at Module._compile (internal/modules/cjs/loader.js:1201:30)at Object.Module._extensions..js (internal/modules/cjs/loader.js:1221:10)at Module.load (internal/modules/cjs/loader.js:1050:32)at Function.Module._load (internal/modules/cjs/loader.js:938:14)at Module.require (internal/modules/cjs/loader.js:1090:19)at require (internal/modules/cjs/helpers.js:75:18)at Object.<anonymous> (D:\Users\IdeaProjects\node_modules\mini-css-extract-plugin\dist\index.js:    at Module._compile (internal/modules/cjs/loader.js:1201:30)at Object.Module._extensions..js (internal/modules/cjs/loader.js:1221:10)
npm ERR! errno 1
npm ERR! cms@1.0.0 build: `vue-cli-service build`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the cms@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:

解决：

安装 webpack。

管理员运行cmd，安装全局webpack

npm install  --save-dev webpack

npm install  --save-dev webpack-cli

或

npm install  -g webpack

二、虽然安装了 webpack，但还是提示找不到

Cannot find module 'webpack' Require stack:

 Building for production... ERROR  Error: Cannot find module 'webpack'Require stack:
- D:\Users\IdeaProjects\node_modules\vue-loader\lib\plugin.js
- D:\Users\IdeaProjects\node_modules\@vue\cli-service\lib\config\base.js
- D:\Users\IdeaProjects\node_modules\@vue\cli-service\lib\Service.js
- D:\Users\IdeaProjects\node_modules\@vue\cli-service\bin\vue-cli-service.js
Error: Cannot find module 'webpack'
Require stack:
- D:\Users\IdeaProjects\node_modules\vue-loader\lib\plugin.js
- D:\Users\IdeaProjects\node_modules\@vue\cli-service\lib\config\base.js
- D:\Users\IdeaProjects\node_modules\@vue\cli-service\lib\Service.js
- D:\Users\IdeaProjects\node_modules\@vue\cli-service\bin\vue-cli-service.jsat Function.Module._resolveFilename (internal/modules/cjs/loader.js:1030:15)at Function.Module._load (internal/modules/cjs/loader.js:899:27)at Module.require (internal/modules/cjs/loader.js:1090:19)at require (internal/modules/cjs/helpers.js:75:18)at Object.<anonymous> (D:\Users\IdeaProjects\node_modules\vue-loader\lib\plugin.js:1:17)        at Module._compile (internal/modules/cjs/loader.js:1201:30)at Object.Module._extensions..js (internal/modules/cjs/loader.js:1221:10)at Function.Module._load (internal/modules/cjs/loader.js:938:14)at Module.require (internal/modules/cjs/loader.js:1090:19)

解决：

npm link webpack

成功执行 npm run build