Looks like a déjà vu of #9.
See on this package viewer:
https://www.jsdelivr.com/package/npm/react-promise?version=2.1.0&path=dist
Clicking on the main file produces 'not found' error:
https://cdn.jsdelivr.net/npm/react-promise@2.1.0/dist/react-promise.cjs.min.js
All seemed fine in 2.0.3: https://cdn.jsdelivr.net/npm/react-promise@2.0.3/dist/react-promise.cjs.min.js
For our create-react-app setup, this causes problem loading the module for testing by Jest, which makes any component using this module untestable.