IE11 support doesn't work in dev mode, even after adding all polyfills and enabling ie11 support

Describe the bug

IE11 support doesn’t work even after adding react-app-polyfill, enabling “ie 11” in browserslist in package.js and adding import ‘react-app-polyfill/ie11’ and import ‘react-app-polyfill/stable’ into src/index.js

Did you try recovering your dependencies?

yes

Which terms did you search for in User Guide?

followed instructions on https://create-react-app.dev/docs/supported-browsers-features/ and https://github.com/facebook/create-react-app/blob/master/packages/react-app-polyfill/README.md

Environment

MacOS node 11.15.0 npm 6.7.0 latest create-react-app Virtual Box with Microsoft’s test Window10 and IE11 image VM

Steps to reproduce

1. npx create-react-app test
2. cd test
3. npm i react-app-polyfill
4. edit package.json and add “ie 11” into “browserslist->development” section:

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

1. edit src/index.js and add 2 lines at the top:

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

1. rm -rf node_modules/.cache
2. npm run start
3. launch IE11 VM and open http://`<ip>`:3000 in IE11

Expected behavior

test create react page is supposed to show up

Actual behavior

SCRIPT5022: SyntaxError 0.chunk.js (19856,1)

[fgeorgsson]

Just ran into this issue as well. Even 3.2.0 does not work for me. Have added polyfill, have added ie11 to browserlist in package.json. Syntax error is thrown at first fat arrow function.

[eyerean]

I confirm the bug, just a small note that version react-scripts@3.2.0 still works, so for a quick fix you can revert back (and delete node_modules/.cache and the browsers’ cache).