import { CheckChatUsernameResultUnion, ErrorUnion } from '../outputs';
/**
 * Checks whether a username can be set for a chat
 * @param {Object} params
 * @param {number} [params.chatId] - Chat identifier; should be identifier of a supergroup
 * chat, or a channel chat, or a private chat with self, or zero if chat is being created
 * @param {string} [params.username] - Username to be checked
 * @param {Object} state
 * @returns {CheckChatUsernameResultUnion | ErrorUnion}
 */
export declare type CheckChatUsernameMethod = <ResponseT = CheckChatUsernameResultUnion>(params: CheckChatUsernameParams, state?: Record<string, any>) => Promise<ResponseT | ErrorUnion>;
export interface CheckChatUsernameParams {
    /**
     * Chat identifier; should be identifier of a supergroup chat, or a channel chat, or
     * a private chat with self, or zero if chat is being created
     */
    chatId?: number;
    /** Username to be checked */
    username?: string;
}