interface ElementSize { width: number; height: number; } type ElementSizeCallback = (size: ElementSize | undefined) => void; declare function trackElementSize(element: HTMLElement | null, callback: ElementSizeCallback): (() => void) | undefined; interface TrackElementsSizeOptions { getNodes: () => T[]; observeMutation?: boolean | undefined; callback: (size: ElementSize | undefined, index: number) => void; } declare function trackElementsSize(options: TrackElementsSizeOptions): () => void; export { type ElementSize, type ElementSizeCallback, trackElementSize, trackElementsSize };