type DisposeReason = 'set' | 'delete' | 'evict' | 'expired';
export interface LRUCacheOptions<K = string, V = unknown> {
    /** The maximum number of items that remain in the cache. default 500 */
    max?: number;
    /** how long to live in ms. default 0 */
    ttl?: number;
    updateAgeOnGet?: boolean;
    /** Function that is called on items when they are dropped from the cache */
    dispose?(val: LRUCacheItem<V>, key: K, reason: DisposeReason): void;
}
interface LRUCacheItem<V> {
    t: number;
    ttl: number;
    v: V;
}
export declare class LRUCache<K = string, V = unknown> {
    protected options: Required<LRUCacheOptions<K, V>>;
    protected cache: Map<K, LRUCacheItem<V>>;
    constructor(options: LRUCacheOptions<K, V>);
    /** Add a value to the cache */
    set<T extends V = V>(key: K, value: T, opts?: {
        ttl?: number;
    }): void;
    /** Return a value from the cache */
    get<T extends V = V>(key: K, options?: {
        updateAgeOnGet?: boolean;
    }): T | undefined;
    /** Deletes a key out of the cache */
    delete(key: K, reason?: DisposeReason): boolean;
    /** Clear the cache */
    clear(): void;
    dump(): [K, LRUCacheItem<V>][];
    load(entries: string | [K, LRUCacheItem<V>][]): void;
    /** Delete any stale entries. */
    purgeStale(): boolean;
    info(): {
        capacity: number;
        /** The total number of items held in the cache at the current moment */
        size: number;
    };
    keys(): K[];
    values(): V[];
}
export {};