import { Dispatch, SetStateAction } from 'react';
export type PersistentStateStorage = 'localStorage' | 'sessionStorage' | 'cookie';
/**
 * 'effect' (default): the stored value is read in a useEffect after mount,
 * so `value` starts as `initialValue` on every render — including the
 * first client render of a component that was server-rendered — and only
 * updates once the effect runs. This is what makes it hydration-safe.
 *
 * 'sync': the stored value is read synchronously during the initial
 * render, so there's no post-mount update and no flash of `initialValue`.
 * Only use this for components that are never part of an SSR/hydration
 * pass (e.g. mounted purely client-side, behind a data-loading gate) —
 * otherwise the server and the first client render will disagree and
 * React will emit a hydration mismatch and force a visible patch-up,
 * which is the exact flash this mode is meant to avoid.
 */
export type PersistentStateHydration = 'effect' | 'sync';
export interface UsePersistentStateOptions<T> {
    initialValue: T;
    storageKey?: string;
    isControlled?: boolean;
    validate?: (value: unknown) => value is T;
    storage?: PersistentStateStorage;
    hydration?: PersistentStateHydration;
    /** Only used when storage is 'cookie'. Defaults to one year. */
    maxAgeSeconds?: number;
}
export interface UsePersistentStateResult<T> {
    value: T;
    setValue: Dispatch<SetStateAction<T>>;
    hydrated: boolean;
}
export declare function usePersistentState<T>({ initialValue, storageKey, isControlled, validate, storage, hydration, maxAgeSeconds, }: UsePersistentStateOptions<T>): UsePersistentStateResult<T>;