ThePromiseRejectionEvent interface represents events which are sent to the global script context when JavaScriptPromises are rejected. These events are particularly useful for telemetry and debugging purposes.

For details, seePromise rejection events.

Constructor

PromiseRejectionEvent()

Creates aPromiseRejectionEvent event, given the type of event (unhandledrejection orrejectionhandled) and other details.

Instance properties

Also inherits properties from its parentEvent.

PromiseRejectionEvent.promiseRead only

The JavaScriptPromise that was rejected.

PromiseRejectionEvent.reasonRead only

A value orObject indicating why the promise was rejected, as passed toPromise.reject().

Instance methods

This interface has no unique methods; inherits methods from its parentEvent.

Events

rejectionhandled

Fired when a JavaScriptPromise is rejected, and after the rejection is handled by the promise's rejection handling code.

unhandledrejection

Fired when a JavaScriptPromise 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

Browser compatibility

See also

• Using promises
• Promise
• rejectionhandled
• unhandledrejection