运行npm install报错：npm WARN deprecated core-js@2.6.12: core-js@<3.23.3 is no longer maintained and not recommended for usage due to the number of issues. Because of the V8 engine whims, feature detection in old core-js versions could cause a slowdown up to 100x even if nothing is polyfilled. Some versions have web compatibility issues. Please, upgrade your dependencies to the actual version of core-js.
字面意思是版本过低不维护，但是使用如下命令还是报错：
npm i core-js 正确方法：
安装淘宝镜像： npm config set registryhttps://registry.npm.taobao.org
（根本原因： npm是国外的，没配置代理 就默认用国外的镜像源， 国内访问国外 肯定访问不同）
然后npm install 就OK啦！