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64 lines (42 loc) · 2.31 KB
title PromiseRejectionEvent
slug Web/API/PromiseRejectionEvent
page-type web-api-interface
browser-compat api.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()")}}

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")}}