Node sass version 6.0.0 is not compatible with ^ 4.0.0
1. Uninstall the previous version of node sass
NPM install node sass
2. Install version 4.0.0 after uninstall
NPM install [email protected]
Here may fail, because you install the Taobao image problem.

If it fails, reload the Taobao image
NPM install – G cnpm — registry= https://registry.npm.taobao.org
After reassembling, perform the second step again

npm install [email protected]

Restart the project NPM run dev