export declare let optionsSupported: boolean; export declare let onceSupported: boolean; export declare type EventHandler = (this: HTMLElement, event: HTMLElementEventMap[K]) => any; export declare type TaggedEventHandler = EventHandler & { __once?: EventHandler; }; /** * An `addEventListener` ponyfill, supports the `once` option */ declare function addEventListener(node: HTMLElement, eventName: K, handler: TaggedEventHandler, options?: boolean | AddEventListenerOptions): void; export default addEventListener;