ie浏览器兼容

npm install react-app-polyfill --save

import "react-app-polyfill/ie11";
import "react-app-polyfill/stable";

  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all",
      "ie 11"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version",
      "ie 11"
    ]
  }