As discussed in an earlier meeting, there are some improvements we should look to make in core-js and across the code base.

1. Avoid swallowing of promise errors by using a different promise lib / polyfill. Bluebird looks promising:
   • http://bluebirdjs.com/docs/features.html#surfacing-unhandled-errors
   • http://jamesknelson.com/are-es6-promises-swallowing-your-errors/
2. We should add test coverage for core-js' Fetch utility especially around the area of error handling. We've just recently had to add more intricate logic for error handling (validation in creation flows) and we should assert these errors propagate when they should, and are caught properly when the UI can gracefully recover.
   • Nock can be used to facilitate this; see this example from smart-fetch: https://github.com/jenkinsci/blueocean-plugin/blob/master/blueocean-dashboard/src/test/js/smart-fetch-spec.js#L16