import { RefCallback, RefObject } from 'react';
type Size = {
    width: number;
    height: number;
    rect: DOMRectReadOnly | null;
};
type UseSizeReturn<TElement extends Element = Element> = Size & {
    ref: RefCallback<TElement>;
};
export declare function useSize<TElement extends Element = Element>(externalRef?: RefObject<TElement | null>): UseSizeReturn<TElement>;
export type { Size, UseSizeReturn };