/**
 * @module
 * WebSocket Helper for Hono.
 */
import type { Context } from '../../context';
import type { MiddlewareHandler } from '../../types';
/**
 * WebSocket Event Listeners type
 */
export interface WSEvents<T = unknown> {
    onOpen?: (evt: Event, ws: WSContext<T>) => void;
    onMessage?: (evt: MessageEvent<WSMessageReceive>, ws: WSContext<T>) => void;
    onClose?: (evt: CloseEvent, ws: WSContext<T>) => void;
    onError?: (evt: Event, ws: WSContext<T>) => void;
}
/**
 * Upgrade WebSocket Type
 */
export type UpgradeWebSocket<T = unknown, U = any> = (createEvents: (c: Context) => WSEvents<T> | Promise<WSEvents<T>>, options?: U) => MiddlewareHandler<any, string, {
    outputFormat: "ws";
}>;
export type WSReadyState = 0 | 1 | 2 | 3;
export type WSContext<T = unknown> = {
    send(source: string | ArrayBuffer | Uint8Array, options?: {
        compress: boolean;
    }): void;
    raw?: T;
    binaryType: BinaryType;
    readyState: WSReadyState;
    url: URL | null;
    protocol: string | null;
    close(code?: number, reason?: string): void;
};
export type WSMessageReceive = string | Blob | ArrayBufferLike;
export declare const createWSMessageEvent: (source: WSMessageReceive) => MessageEvent<WSMessageReceive>;