interface GetOptions {
    removeStale?: boolean;
    updateAge?: boolean;
}
interface SetOptions {
    ttl?: number | string;
}
declare class StorageEnhancer {
    storage: Storage;
    constructor(storage: Storage);
    /**
     * detect whether key is in storage
     *
     * @param {string} key
     * @returns {boolean}
     */
    hasItem(key: string): boolean;
    /**
     * detect whether key is still alive
     *
     * @param {string} key
     * @returns {boolean} - return true only if key existed and staled
     */
    staleItem(key: string): boolean;
    /**
     * get item via key
     *
     * @param {string} key
     * @param {GetOptions} options
     * @param {boolean} options.removeStale - whether remove item when key staled
     * @param {boolean} options.updateAge - whether delay key ttl
     * @returns {string | null}
     */
    getItem(key: string, { removeStale, updateAge }?: GetOptions): string | null;
    /**
     * set item via key
     *
     * @param {string} key
     * @param {string} value
     * @param {SetOptions} options
     * @param {number} options.ttl - key's time to live, ms
     * @returns {void}
     */
    setItem(key: string, value: string, { ttl }?: SetOptions): void;
    /**
     * get json via key
     *
     * @param {string} key
     * @param {GetOptions} options
     * @param {boolean} options.removeStale - whether remove item when key staled
     * @param {boolean} options.updateAge - whether delay key ttl
     * @returns {string | object | null}
     */
    getJson(key: string, options?: GetOptions): any;
    /**
     * set json via key
     *
     * @param {string} key
     * @param {string} value
     * @param {SetOptions} options
     * @param {number} options.ttl - key's time to live, ms
     * @returns {void}
     */
    setJson(key: string, value: object, options?: SetOptions): void;
    /**
     * remove item via key
     *
     * @param {string} key
     * @returns {void}
     */
    removeItem(key: string): void;
    /**
     * clear all keys and items
     *
     * @returns {void}
     */
    clear(): void;
    _prependExpire(value: string, ttl?: number | string | null): string;
    _parseValue(value: string): {
        value: string;
        start: string | null;
        ttl: string | null;
    };
    _isStale(start?: number | string | null, ttl?: number | string | null): boolean;
    _isNumber(n: any): boolean;
}

export { StorageEnhancer };