Browser Request Cancellation Test

https://request-cancellation-test.vercel.app

What Is This?

This website details the error when a fetch request gets cancelled in this browser.

Most browsers will cancel ongoing or queued fetch tasks, when unloading the document (spec). It usually happens when navigating away from the current page, which causes a fetch error if there is an unfinished request.

However, browsers are behaving differently and throwing different errors (listed below). It can be really annoying to differentiate them from normal errors if you are using Sentry, or showing a “failed to fetch” hint in the UI.

Test Results for Common Browsers

Field	Chrome 95	Safari 14	iOS Safari 14	Firefox 94
.toString()	TypeError: Failed to fetch	TypeError: cancelled	TypeError: cancelled	TypeError: NetworkError when attempting to fetch resource.
.name	TypeError	TypeError	TypeError	TypeError
.message	Failed to fetch	cancelled	cancelled	NetworkError when attempting to fetch resource.
.stack	TypeError: Failed to fetch at ...