Ir para o conteúdo principal
Version: 4.x

Version 4.8.0

September 21, 2024

Server

Bug Fixes

  • allow to join a room in a middleware (uws) (b04fa64)
  • correctly await async close on adapters (#4971) (e347a3c)
  • expose type of default engine (132d05f)

Dependencies

Client

Features

Custom transport implementations

The transports option now accepts an array of transport implementations:

import { io } from "socket.io-client";
import { Fetch, WebSocket } from "engine.io-client";

const socket = io({
transports: [Fetch, WebSocket]
});

Here is the list of provided implementations:

TransportDescription
FetchHTTP long-polling based on the built-in fetch() method.
NodeXHRHTTP long-polling based on the XMLHttpRequest object provided by the xmlhttprequest-ssl package.
XHRHTTP long-polling based on the built-in XMLHttpRequest object.
NodeWebSocketWebSocket transport based on the WebSocket object provided by the ws package.
WebSocketWebSocket transport based on the built-in WebSocket object.
WebTransportWebTransport transport based on the built-in WebTransport object.

Usage:

TransportbrowserNode.jsDenoBun
Fetch✅ (1)
NodeXHR
XHR
NodeWebSocket
WebSocket✅ (2)
WebTransport

(1) since v18.0.0 (2) since v21.0.0

Added in f4d898e and b11763b.

Test each low-level transports

When setting the tryAllTransports option to true, if the first transport (usually, HTTP long-polling) fails, then the other transports will be tested too:

import { io } from "socket.io-client";

const socket = io({
tryAllTransports: true
});

This feature is useful in two cases:

  • when HTTP long-polling is disabled on the server, or if CORS fails
  • when WebSocket is tested first (with transports: ["websocket", "polling"])

The only potential downside is that the connection attempt could take more time in case of failure, as there have been reports of WebSocket connection errors taking several seconds before being detected (that's one reason for using HTTP long-polling first). That's why the option defaults to false for now.

Added in 579b243.

Bug Fixes

  • accept string | undefined as init argument (bis) (60c757f)
  • allow to manually stop the reconnection loop (13c6d2e)
  • close the engine upon decoding exception (04c8dd9)
  • do not send a packet on an expired connection (#5134) (8adcfbf)

Dependencies