import { Clock } from '@croct/time';
import { CacheLoader, CacheProvider } from './cacheProvider';
import { TimestampedCacheEntry } from './timestampedCacheEntry';
type Configuration<K, V> = {
    /**
     * The underlying cache provider to use for storing the cached data.
     */
    cacheProvider: CacheProvider<K, TimestampedCacheEntry<V>>;
    /**
     * The freshness period of the cached data in seconds.
     *
     * It defines the time duration for which the cache entry
     * is considered fresh. Once the freshness period expires,
     * the data will be revalidated in the background while
     * still serving the stale value on subsequent gets.
     *
     * For example, if freshPeriod is set to 60 seconds,
     * the cache entry will be considered fresh for 60 seconds
     * after its creation or update. After 60 seconds, it will be
     * evaluated in the background on subsequent gets, but the stale value
     * will still be served until the revalidation is complete.
     */
    freshPeriod: number;
    /**
     * The clock to use for time-related operations.
     *
     * It is used for retrieving the current time and for time calculations.
     * If not provided, the default clock is used.
     *
     * @default DefaultClockProvider.getClock()
     */
    clock?: Clock;
    /**
     * The handler for background revalidation errors.
     *
     * It is a function that is called when an error occurs during
     * background revalidation of a cache entry. If not provided,
     * errors during background revalidation are ignored.
     *
     * The most common use case for this handler is logging.
     */
    errorHandler?: (error: Error) => void;
};
export declare class StaleWhileRevalidateCache<K, V> implements CacheProvider<K, V> {
    private readonly cacheProvider;
    private readonly freshPeriod;
    private readonly clock;
    private readonly errorHandler;
    constructor(config: Configuration<K, V>);
    get(key: K, loader: CacheLoader<K, V>): Promise<V>;
    set(key: K, value: V): Promise<void>;
    delete(key: K): Promise<void>;
}
export {};