In this tutorial, you will learn how to configure CreateReactApp with IE11. IE11 is old and for the majority of projects not supported and rightly so. If you do need to support IE this quick start guide will get you going.
Within package.json, find the development object and add this:
Most apps will require AJAX so you will likely want to use fetch. IE11 does not support fetch natively, so you will need to add a polyfill. To do this, use:
index.jsat the very top of the file, add this:
That should be it. Your site and API request should now work n IE11... commiserations!