Looks like @ionic/app-scripts isn't installed in this project.

百度之后参考以下链接

https://blog.csdn.net/liweibo348/article/details/83625221

本地删除node_modules文件夹，然后npm install 报错：Failed at the [email protected] postinstall script.

不管它，继续ionic serve，报错

 之后执行：npm install @ionic/[email protected] --save-dev

根据提示，执行 npm audit fix，npm audit fix --force

最后执行 ionic serve，成功啦