import type { ListenerTimer, Register, Unregister } from "../types";
/**
 * Calls `callback` after at least `duration` milliseconds. Returns a function that cancels the future call of `callback`, if not already called.
 * If the `duration` is `0`, it uses `requestAnimationFrame` if available.
 *
 * @param duration Timeout duration in milliseconds.
 * @param callback Called after the `duration` elapsed.
 * @returns Function that cancels the call of `callback`.
 */
export declare function timeout(duration: number, callback: ListenerTimer): Unregister;
/**
 * Returns a function that registers a `callback` to be called after at least `duration` milliseconds elapsed.
 * If the `duration` is `0`, if uses `requestAnimationFrame` if available.
 * The timer is set during this call.
 *
 * @param duration Timeout duration in milliseconds.
 * @returns Function that registers a callback to call after the `duration` elapsed, and returns a function that unregisters it. If the latter function unregisters the last callback, it clears the timeout.
 */
export declare function timeout(duration: number): Register<ListenerTimer, undefined>;