Resolving Promise returned by fetch() is now deferred during page load

Published: | Categories: DOM, Networking


Starting with Firefox 69, a Promise returned by fetch() during page load won’t be resolved until an idle time is available or the loading is complete. This change aims at improving page load performance, just like similar changes recently made to setTimeout() and XMLHttpRequest, but unexpected race conditions may occur if the initialization code is not designed properly. Make sure to test your site if applicable.