/**
 * A ponyfill for requestIdleCallback that falls back to setTimeout.
 * Uses the native requestIdleCallback when available.
 *
 * @param callback - The function to call when the browser is idle.
 * @param options - Options object that may contain a timeout property.
 * @returns An ID that can be used to cancel the callback.
 * @public
 */
export declare function requestIdleCallback(callback: (deadline: IdleDeadline) => void, options?: {
    timeout: number;
}): ReturnType<typeof globalThis.requestIdleCallback | typeof setTimeout>;
/**
 * A ponyfill for cancelIdleCallback that falls back to clearTimeout.
 * Uses the native cancelIdleCallback when available.
 *
 * @param id - The ID of the callback to cancel.
 * @public
 */
export declare function cancelIdleCallback(id: ReturnType<typeof globalThis.requestIdleCallback | typeof setTimeout>): void;
/**
 * Waits for all custom element descendants of a target element to be connected.
 *
 * @param target - The target element to observe.
 * @param callback - The function to call when all custom element descendants are connected.
 * @param options - Options object that may contain a timeout property for the idle callback.
 *
 * @remarks
 * This function uses requestIdleCallback to periodically check if all custom element
 * descendants (elements with a hyphen in their tag name) are connected to the DOM.
 * Once all such elements are connected, the provided callback is invoked.
 *
 * The `timeout` option specifies the maximum time to wait for each idle callback before
 * rechecking, defaulting to 50 milliseconds.
 *
 * @public
 */
export declare function waitForConnectedDescendants(target: HTMLElement, callback: () => void, options?: {
    /**
     * Whether to only check direct children of the target element, rather than all descendants.
     * @defaultValue `false`
     */
    shallow?: boolean;
    /**
     * The maximum time to wait for each idle callback before rechecking for connected descendants, in milliseconds.
     * @defaultValue `50`
     */
    timeout?: number;
    /**
     * Whether to call the callback on the next idle period after descendants are connected, rather than immediately.
     * This can be used to defer work until after the browser has had a chance to perform any necessary updates
     * following the connection of the descendants.
     * @defaultValue `false`
     */
    idleCallback?: boolean;
}): void;