import { ArCacheInterface } from '../faces/utils/arCache';
/**
 * Implementation of a simple in-memory cache.
 */
export default class ArCache implements ArCacheInterface {
    private _cache;
    private _size;
    private _maxMemSize;
    private _itemsToDelete;
    private _defaultTtl;
    get size(): number;
    get memSize(): number;
    /**
     * @param {number=0} ttl - Time to live in seconds, Default 0 (never).
     * @param  {number=2e+6} maxMemSize - Maximum memory size in bytes, default is 2MB.
     * @param  {number=3} itemsToDelete - Number of items to delete when cache is full.
     */
    constructor(ttl?: number, maxMemSize?: number, itemsToDelete?: number);
    /**
     * Add a new item to the cache.
     * @param  {string} key
     * @param  {any} value
     * @param {number} ttl - Time to live in seconds, 0 or null means never expires.
     * @returns {Promise<void>}
     */
    set(key: string, value: any, ttl?: number): Promise<void>;
    /**
     * Get a specific item from the cache.
     * @param  {string} key
     * @returns {any}
     */
    get(key: string): Promise<any>;
    /**
     * Delete a specific item from the cache.
     * @param  {string} key
     */
    del(key: string): void;
    /**
     * Clear the cache.
     */
    clear(): void;
    /**
     * Check wether an item has expired.
     * @param  {string} key
     * @returns boolean
     */
    hasExpired(key: string): boolean;
    /**
     * Delete old stored data from cache when the maxMemSize is reached to make room for new content.
     * @private
     */
    private makeRoom;
    /**
     * Get the rough size of the cache.
     * @param {object} obj
     * @private
     */
    private roughSizeof;
}