PromiseRejectionEvent: reason property

Note: This feature is available in Web Workers.

The PromiseRejectionEvent reason read-only property is any JavaScript value or Object which provides the reason passed into Promise.reject(). This in theory provides information about why the promise was rejected.

Value

A value or object which provides information you can use to understand why the promise was rejected. This could be anything from an error code to an object with text, links, and whatever else you might wish to include.

Examples

js
window.onunhandledrejection = (e) => {
  console.log(e.reason);
};

Specifications

Specification
HTML
# dom-promiserejectionevent-reason

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
reason

Legend

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Full support
Full support

See also