// @flow class DOMRectReadOnly { +x: number; +y: number; +width: number; +height: number; +top: number; +right: number; +bottom: number; +left: number; } class ResizeObserverEntry { +target: Element; +contentRect: DOMRectReadOnly; } type Entries = $ReadOnlyArray; type ResizeObserverCallback = { (entries: Entries, observer: ResizeObserver): void }; declare class ResizeObserver { constructor(ResizeObserverCallback): ResizeObserver; observe(target: Element): void; unobserve(target: Element): void; disconnect(): void; }; declare export default typeof ResizeObserver;