PromiseRejectionEvent: reason property

{{APIRef("HTML DOM")}}{{AvailableInWorkers}}

The {{domxref("PromiseRejectionEvent")}} reason read-only property is any JavaScript value or {{jsxref("Object")}} which provides the reason passed into {{jsxref("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

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{jsxref("Promise")}}
• {{domxref("PromiseRejectionEvent")}}
• {{domxref("Window.rejectionhandled_event", "rejectionhandled")}}
• {{domxref("Window.unhandledrejection_event", "unhandledrejection")}}