import { BlockHash, StorageData, StorageKey } from '@dedot/codecs';
import type { Callback, Unsub } from '@dedot/types';
import { V2Client } from '../client/V2Client.js';
import { BaseStorageQuery } from './BaseStorageQuery.js';
/**
 * @name NewStorageQuery
 * @description
 * Implementation of BaseStorageQuery for the new JSON-RPC API (v2).
 * This service handles storage queries using the chainHead_storage RPC method
 * and chainHead events for subscriptions.
 *
 * It provides:
 * - One-time queries using chainHead_storage
 * - Subscriptions using chainHead 'bestBlock' events
 * - Efficient change detection for subscriptions
 */
export declare class NewStorageQuery extends BaseStorageQuery {
    protected client: V2Client<any>;
    constructor(client: V2Client<any>);
    /**
     * Query multiple storage items in a single call using chainHead_storage
     *
     * @param keys - Array of storage keys to query
     * @param at - Optional block hash to query at (defaults to best block)
     * @returns Promise resolving to a record mapping storage keys to their values
     */
    query(keys: StorageKey[], at?: BlockHash): Promise<Record<StorageKey, StorageData | undefined>>;
    /**
     * Subscribe to multiple storage items using chainHead 'bestBlock' events
     *
     * @param keys - Array of storage keys to subscribe to
     * @param callback - Function to call when storage values change
     * @returns Promise resolving to an unsubscribe function
     */
    subscribe(keys: StorageKey[], callback: Callback<Record<StorageKey, StorageData | undefined>>): Promise<Unsub>;
}