import type React from 'react';
export declare function useIframeContentHeight({ interval, skip, viewport, }: {
    interval?: number;
    skip?: boolean;
    viewport?: number | null;
}): [React.MutableRefObject<HTMLIFrameElement | null>, number | undefined, number];
type CallbackFn = () => void;
export declare function useInterval(callback: CallbackFn, interval: number): void;
export {};