React 啓動報錯：
Failed to compile.
./node_modules/react-dev-utils/formatWebpackMessages.js
Module not found: Can't resolve 'D:\react\yunkj\node_modules\babel-preset-react-app\node_modules\@babel\runtime/helpers/slicedToArray' in 'D:\react\yunkj\node_modules\react-dev-utils'
Compiling...
執行指令：
npm add @babel/runtime
問題解決。