/**
 * Configuration options for the cache
 */
interface CacheOptions {
    /** Maximum age in ms for fresh data */
    maxAge: number;
    /** Maximum age in ms for stale data */
    staleWhileRevalidate: number;
    /** Maximum number of entries before LRU eviction */
    maxEntries?: number;
}
/**
 * In-memory cache with stale-while-revalidate semantics.
 * - Returns fresh data if within maxAge
 * - Returns stale data if within staleWhileRevalidate while refreshing in the background
 * - Fetches new data if beyond staleWhileRevalidate
 */
export declare class Cache<T> {
    private cache;
    private options;
    private fetchPromises;
    constructor(options?: Partial<CacheOptions>);
    /**
     * Evict the least recently used entries if we exceed the maximum size
     */
    private evictLRUIfNeeded;
    /**
     * Get an item from the cache or fetch it
     * @param key Cache key
     * @param fetchFn Function to fetch the data if not in cache
     * @returns The cached or newly fetched data
     */
    get(key: string, fetchFn: () => Promise<T>): Promise<T>;
    /**
     * Force a refresh of the cached item
     * @param key Cache key
     * @param fetchFn Function to fetch the data
     * @returns The newly fetched data
     */
    refresh(key: string, fetchFn: () => Promise<T>): Promise<T>;
    /**
     * Clear a specific item from the cache
     * @param key Cache key to clear
     */
    invalidate(key: string): void;
    /**
     * Clear the entire cache
     */
    clear(): void;
    /**
     * Check if an item exists in the cache
     * @param key Cache key
     * @returns True if the item exists in the cache
     */
    has(key: string): boolean;
    /**
     * Refresh data in the background without blocking
     */
    private refreshInBackground;
    /**
     * Fetch and cache data
     */
    private fetchAndCache;
}
export {};