PromiseRejectionEvent

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

The PromiseRejectionEvent interface represents events which are sent to the global script context when JavaScript {{jsxref("Promise")}}s are rejected. These events are particularly useful for telemetry and debugging purposes.

For details, see Promise rejection events.

{{InheritanceDiagram}}

Constructor

• {{domxref("PromiseRejectionEvent.PromiseRejectionEvent", "PromiseRejectionEvent()")}}
  • : Creates a PromiseRejectionEvent event, given the type of event (unhandledrejection or rejectionhandled) and other details.

Instance properties

Also inherits properties from its parent {{domxref("Event")}}.

• {{domxref("PromiseRejectionEvent.promise")}} {{ReadOnlyInline}}
  • : The JavaScript {{jsxref("Promise")}} that was rejected.
• {{domxref("PromiseRejectionEvent.reason")}} {{ReadOnlyInline}}
  • : A value or {{jsxref("Object")}} indicating why the promise was rejected, as passed to {{jsxref("Promise.reject()")}}.

Instance methods

This interface has no unique methods; inherits methods from its parent {{domxref("Event")}}.

Events

• {{domxref("Window/rejectionhandled_event", "rejectionhandled")}}
  • : Fired when a JavaScript {{jsxref("Promise")}} is rejected, and after the rejection is handled by the promise's rejection handling code.
• {{domxref("Window/unhandledrejection_event", "unhandledrejection")}}
  • : Fired when a JavaScript {{jsxref("Promise")}} is rejected but there is no rejection handler to deal with the rejection.

Examples

This simple example catches unhandled promise rejections and logs them for debugging purposes.

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Using promises
• {{jsxref("Promise")}}
• {{domxref("Window/rejectionhandled_event", "rejectionhandled")}}
• {{domxref("Window/unhandledrejection_event", "unhandledrejection")}}