type OpaqueStore = {
    set: (key: string, value: Record<string, unknown>, options?: {
        expiresIn?: string | number;
    }) => Promise<void>;
    /**
     *   Must return `null` once the entry's TTL has passed — expiry is the
     *   store's responsibility, not this package's.
     */
    get: (key: string) => Promise<Record<string, unknown> | null>;
    delete: (key: string) => Promise<boolean>;
};

/**
 * @typedef {object} MemoryStoreOptions
 * @property {number} [sweepMs=60000]  Interval for the background TTL sweep.
 */
/**
 * @param {MemoryStoreOptions} [options]
 * @returns {import('../index.js').OpaqueStore & { _size: () => number, stop: () => void }}
 */
declare function memoryStore(options?: MemoryStoreOptions): OpaqueStore & {
    _size: () => number;
    stop: () => void;
};
type MemoryStoreOptions = {
    /**
     * Interval for the background TTL sweep.
     */
    sweepMs?: number | undefined;
};

/**
 * @typedef {object} RedisStoreOptions
 * @property {string} [keyPrefix='opaque:']
 */
/**
 * @param {any} client
 * @param {RedisStoreOptions} [options]
 * @returns {import('../index.js').OpaqueStore}
 */
declare function redisStore(client: any, options?: RedisStoreOptions): OpaqueStore;
type RedisStoreOptions = {
    keyPrefix?: string | undefined;
};

declare const customStore: (impl: object) => Record<string, (...args: any[]) => Promise<any>>;

export { customStore, memoryStore, redisStore };