401 (Unauthorized) in Chrome, but not in IE
I suppose you have cookie-based authentication on server. In this case it could be related to credentials key for fetch. XHR requests, that used in jQuery always send your cookie, but using fetch you should pass credentials option with
same-originif you make request to the same origin (domain)includeotherwise
Like this:
...fetch(API_URI_HERE, {credentials: 'same-origin'})...I assume that it works in IE because fetch polyfill uses XHR requests under the hood.