#import 
// https://html.spec.whatwg.org/#promiserejectionevent
[Exposed=(Window,Worker)]
interface PromiseRejectionEvent : Event {
    constructor(DOMString type, PromiseRejectionEventInit eventInitDict);
    readonly attribute Promise promise;
    readonly attribute any reason;
};
dictionary PromiseRejectionEventInit : EventInit {
    required Promise promise;
    any reason;
};