index.js.flow

// @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<ResizeObserverEntry>;

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;