export declare type Cacheable = string | number | boolean | object;
export declare type OnCacheMiss<T extends Cacheable = Cacheable> = (key: string) => Promise<T>;
export interface CacheItem<T extends Cacheable = Cacheable> {
    data: T;
    expiresAt: number;
}
export interface CacheStore<T extends Cacheable = Cacheable> {
    get: (key: string) => Promise<CacheItem<T> | null>;
    set: (key: string, data: CacheItem<T>, ttl: number) => Promise<boolean>;
    del: (key: string) => Promise<boolean>;
    lock: (key: string, ttl: number) => Promise<string | false>;
    unlock: (key: string, lockId: string) => Promise<boolean>;
}
export interface LeprechaunCacheOptions<T extends Cacheable = Cacheable> {
    keyPrefix?: string;
    softTtlMs: number;
    hardTtlMs: number;
    lockTtlMs: number;
    waitTimeMs?: number;
    waitForUnlockMs: number;
    cacheStore: CacheStore<T>;
    spinMs: number;
    returnStale: boolean;
    onMiss: OnCacheMiss<T>;
    onBackgroundError?: (e: Error) => void;
}