/**
 * Tracks visual viewport size.
 *
 * ⚗️ _The underlying technology is experimental. Please be aware about browser compatibility before using this in production._
 *
 * @returns Dimensions `[width, height]`, falling back to `[0, 0]` when unavailable.
 *
 * @example
 * function Component() {
 *   const [viewportWidth, viewportHeight] = useViewportSize();
 *   // ...
 * }
 */
export default function useViewportSize(): Readonly<[number, number]>;