$ npm i
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR!
npm ERR! While resolving: undefined@undefined
npm ERR! Found: umi@3.3.9
npm ERR! node_modules/umi
npm ERR!   umi@"^3.3.7" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer umi@"3.0.0-beta.20" from @alitajs/hd@2.7.6
npm ERR! node_modules/@alitajs/hd
npm ERR!   @alitajs/hd@"^2.6.16" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR!
npm ERR! See C:\Users\Administrator\AppData\Local\npm-cache\eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\Administrator\AppData\Local\npm-cache\_logs\2021-03-01T08_44_38_190Z-debug.log

React重啟項目報錯是因為自己沒注意修改了淘寶鏡像，所以試試 cnpm
先刪除

rm -rf node_modules/

在安裝

 cnpm install gulp-sass --save-dev

最后

 cnpm install

啟動項目

npm   start