import { TTL, GetValue } from '../types';
declare class BaseStorageApi {
    private persistent;
    private _lootBag;
    private _ttl;
    constructor(persistent: boolean);
    /**
    * @public
    * @param ttlValue - number of seconds to set. applies to all
    *                   keys that don't have a key-leve ttl set.
    */
    set timeoutInSeconds(ttlValue: TTL);
    /**
    * @public
    * @returns ttl in seconds which applies to all keys that don't
    *          have a key-level ttl set.
    */
    get timeoutInSeconds(): TTL;
    /**
    * @public
    * @param key - name of key
    * @param val - data to be stored
    * @param keyTimeout - optional key-level ttl in seconds. The key level
    *                     ttl overrides the global ttl if it had been set.
    */
    put(key: string, val: any, keyTimeout?: TTL): void;
    /**
    * @public
    * @param key - key to access stored data
    * @param defaultValue - optional data if key does not exist.
    * @returns any or null
    */
    get(key: string, defaultValue?: GetValue): GetValue;
    /**
    * @public
    * @param key
    */
    removeKey(key: string): void;
    /**
    * @public
    * @param key - key used to store data
    * @returns true if key exists and not stale, false otherwise
    */
    keyExists(key: string): boolean;
    /**
    * Remove all keys in storage
    * @public
    */
    clear(): void;
    /**
     * @public
     * @returns list of keys
     */
    keys(): string[];
    /**
    * Remove keys that are detected to be stale. Leave other keys intact. This
    * method is executed only if invoked by an explicit call by the developer who
    * uses this library; it is not an automatic garbage collector mechanism.
    * @public
    * @returns list of keys that were deleted
    */
    runGarbageCollector(): string[];
    /**
     * @public
     * @returns true if browser's localStorage is available, false otherwise
     */
    isLocalStorageAvailable(): boolean;
    /**
    * @private
    * @returns unix time
    */
    private _getNow;
    /**
    * This method is called only when at least one of the timeouts has been set.
    * key timeout has priority. global this._ttl is used only if a key-level
    * timeout hasn't been set.
    *
    * @private
    * @param obj - retrieved data from storage
    * @returns true if key is stale, false otherwise
    */
    private _isCacheStale;
    /**
    * @private
    * @param n - ostensibly a positive integer
    * @returns true if a positive integer, false otherwise
    */
    private static isPositiveInteger;
}
export { BaseStorageApi };