yarn add react-app-polyfill core-js
在index.js
import ‘react-app-polyfill/ie9‘;//兼容ie9 import ‘react-app-polyfill/stable‘; import "core-js/es/map" import "core-js/es/set"
create-react-app 兼容 ie9
原文：https://www.cnblogs.com/lxz-blogs/p/13718787.html
