/**
 * Adds an event listener that is removed after the first call.
 *
 * @param el - The target element.
 * @param event - The event name.
 * @param handler - The event handler.
 * @returns A cleanup function.
 *
 * @example
 * const el = document.createElement('button')
 * document.body.appendChild(el)
 * onceEvent(el, 'click', () => console.log('clicked once'))
 * el.click()
 *
 * @since 1.0.0
 */
declare const onceEvent: <K extends keyof GlobalEventHandlersEventMap>(el: EventTarget, event: K, handler: (event: GlobalEventHandlersEventMap[K]) => void) => (() => void);
export default onceEvent;