使用vue-antd-jeecg前端 run build 的坑

> vue-cli-service build

-  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 null
    at Object. (Z:\code\yxt\yxt-web\node_modules\mini-css-extract-plugin\dist\CssDependency.js:12:46)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Module.require (internal/modules/cjs/loader.js:952:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at Object. (Z:\code\yxt\yxt-web\node_modules\mini-css-extract-plugin\dist\index.js:12:45)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] build: `vue-cli-service build`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

错误原因 : 使用npm install

正确方式如下：

1. 将node_modules文件删除
2. 安装yarn: npm i yarn
3. 使用yarn安装node_modules（注意！注意！注意！不能用其他方式，例如npm install） yarn install