export declare class ResizeObserver { constructor ( callback ) ; disconnect : ( ) => void ; observe : ( target : Element , options ? : ResizeObserverObserveOptions ) => void ; unobserve : ( target : Element ) => void ; } export interface ResizeObserverEntry { readonly borderBoxSize : ResizeObserverEntryBoxSize ; readonly contentBoxSize : ResizeObserverEntryBoxSize ; readonly contentRect : DOMRectReadOnly ; readonly target : Element ; } export interface ResizeObserverObserveOptions { box ? : 'content-box' | 'border-box' ; } export type ResizeObserverCallback = ( entries : ResizeObserverEntry [ ] , observer : ResizeObserver ) => void ; export interface ResizeObserverEntryBoxSize { blockSize : number ; inlineSize : number ; }