/**
 * A React hook to manage a single cookie value.
 * The component will re-render when the cookie value changes.
 *
 * @param key The name of the cookie.
 * @param defaultValue The default value if the cookie is not set.
 * @returns A state-like array: [value, updateValue, removeValue].
 */
export declare function useCookie(key: string, defaultValue?: string): [string | undefined, (newValue: string, days?: number) => void, () => void];