/**
 * Tracks visual viewport scale.
 *
 * ⚗️ _The underlying technology is experimental. Please be aware about browser compatibility before using this in production._
 *
 * @returns Pinch-zoom scaling factor, falling back to `0` when unavailable.
 *
 * @example
 * function Component() {
 *   const viewportScale = useViewportScale();
 *   // ...
 * }
 */
export default function useViewportScale(): number;