import { IUseCountryReturn } from '../types';
/**
 * A unified hook that returns all metadata and helper values related to a country in a single call.
 * Highly optimized with multi-level caching, early exits, and minimal string operations.
 *
 * Performance optimizations:
 * - Two-level cache by length for O(1) rejection of invalid codes
 * - Skips toUpperCase() if string is already uppercase (common case)
 * - Early exit for null/undefined inputs
 * - Memoized normalization to prevent unnecessary re-computations
 *
 * @param countryIso2 ISO2 country code (case-insensitive)
 * @returns Country metadata including divisions, timezones, currency, phone format, and tax/postal info
 */
export declare function useCountry(countryIso2?: string | null): IUseCountryReturn;