import { MiddlewareFn } from '@pql/client';
export interface ICacheStorage {
    read(hash: any): Promise<any>;
    write(hash: any, value: any): Promise<any>;
    invalidate(hash: any): Promise<any>;
    invalidateAll(): Promise<any>;
}
export declare function cache(storage: ICacheStorage): MiddlewareFn<any, any>;
export declare class DefaultStorage implements ICacheStorage {
    private cache;
    constructor(initial?: {
        [hash: string]: any;
    });
    read(hash: any): Promise<any>;
    write(hash: any, value: any): Promise<unknown>;
    invalidate(hash: any): Promise<unknown>;
    invalidateAll(): Promise<{}>;
}