问题一.vue项目启动时npm run serve报错：Error: Cannot find module ‘webpack’ Require stack

项目拉下来以后，正常安装完依赖，启动项目时报Error: Cannot find module ‘webpack’ Require stack，发现是缺少webpack模块，

Error: Cannot find module 'webpack'
Require stack:
  at Function.Module._load (internal/modules/cjs/loader.js:725:27)
    at Module.require (internal/modules/cjs/loader.js:952:19)
    at require (internal/modules/cjs/helpers.js:88:18)

但是我已经安装过webpack了，这里需要重新打开cmd，全局安装webpack

原因：

就算之前你装了webpack，那肯定是非全局安装

解决：

npm install  -g webpack

安装完成以后，启动项目发现又报错了！！！
报错：Error: Rule can only have one resource source (provided resource and test + include + exclude) in

问题二：项目报错：Error: Rule can only have one resource source (provided resource and test + include + exclude) in

Error: Rule can only have one resource source (provided resource and test + include + exclude) in {
    
    
  "exclude": [
    null
  ]

原因：

package.json中webpack版本冲突问题。

解决：

删除webpack，重新装以前的版本。

npm uninstall webpack
npm install webpack@^4.0.0 --save-dev