react ecom toturial 源码

笔记 较旧的React版本 "react": "^16.13.1", "react-dom": "^16.13.1", "react-scripts": "3.4.3", 当前的React版本 "react": "^17.0.1", "react-dom": "^17.0.1", "react-scripts": "4.0.0",