import type { StorageService as IStorageService } from './types';
export declare class StorageService implements IStorageService {
    #private;
    constructor(adapter: IStorageService);
    getItem<Value = unknown>(key: string): Promise<Value | null>;
    getItemSync<Value = unknown>(key: string): Value | null;
    setItem<Value = unknown>(key: string, value: Value): Promise<void>;
    setItemSync<Value = unknown>(key: string, value: Value): void;
    clearItem(key: string): void;
    clear(): void;
    has(key: string): boolean;
}