The PromiseRejectionEvent interface represents events which are sent to the global script context when JavaScript Promises are rejected. These events are particularly useful for telemetry and debugging purposes.
PromiseRejectionEvent
Promise
For details on promise rejection events, see Promise rejection events in Using Promises.
PromiseRejectionEvent()
Creates a PromiseRejectionEvent event, given the type of event (unhandledrejection or rejectionhandled) and other details.
unhandledrejection
rejectionhandled
Also inherits properties from its parent Event.
Event
PromiseRejectionEvent.promise
The JavaScript Promise that was rejected.
PromiseRejectionEvent.reason
A value or Object indicating why the promise was rejected, as passed to Promise.reject().
Object
Promise.reject()
This interface has no unique methods; inherits methods from its parent Event.
Fired when a JavaScript Promise is rejected, and after the rejection is handled by the promise's rejection handling code.
Fired when a JavaScript Promise is rejected but there is no rejection handler to deal with the rejection.
This simple example catches unhandled promise rejections and logs them for debugging purposes.
window.onunhandledrejection = function(e) { console.log(e.reason); }
promise
reason
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