How do I support IE 11 with Create React App 3.0?

To stop the errors and get a default create-react-app React application working in IE 11:

1. Create your basic application with npx create-react-app [AppName]
2. Add import 'react-app-polyfill/ie11'; to the VERY top of index.js
3. If you need common standard functions like Array.find() that are not supported in IE 11 add import 'react-app-polyfill/stable'; just below the first line in index.js
4. In package.json copy the production browserlist to development so you can test in IE11 and all other browsers that will work in production
5. Delete the node_modules/.cache directory