PromiseRejectionEvent: promise property
Note: This feature is available in Web Workers.
The PromiseRejectionEvent
interface's
promise
read-only property indicates the JavaScript
Promise
which was rejected. You can examine the event's
PromiseRejectionEvent.reason
property to learn why the promise was
rejected.
Value
The JavaScript Promise
which was rejected, and whose rejection went
unhandled.
Examples
This example listens for unhandled promises and, if the
reason
is an object with a
code
field containing the text "Module not ready", it sets up an idle
callback that will retry the task that failed to execute correctly.
event.preventDefault()
is called to indicate that the promise has now
been handled.
js
window.onunhandledrejection = (event) => {
if (event.reason?.code === "Module not ready") {
requestIdleCallback((deadline) => {
loadModule(event.reason.moduleName).then(performStartup);
});
event.preventDefault();
}
};
Specifications
Specification |
---|
HTML Standard # dom-promiserejectionevent-promise |
Browser compatibility
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