This error was reported when configuring the loader in vue.config.js. The reason is that there is no module configuration item in vue-cli.
The module is used to configure the loader in webpack.config.js
css is used to configure the loader in vue.config.js
correct answer:
Attachment: vue-cli css.loaderOptions official website link
Finally, if you find a problem, welcome to criticize and correct in the comment area, welcome to communicate with each other ^0^!