Due to a change in the bundler configuration, the production bundle (socket.io.min.js) did not support sending and receiving binary data in version 4.8.0. This is now fixed.

• engine.io@~6.6.0 (no change)
• ws@~8.17.1 (no change)

• bundle: do not mangle the "_placeholder" attribute (ca9e994)

• engine.io-client@~6.6.1 (no change)
• ws@~8.17.1 (no change)

• types: remove ws type from .d.ts file (175a2c5)
• prevent infinite loop with Node.js built-in WebSocket (4865f2e)

• ws@~8.17.1 (no change)

This release contains a bump of the cookie dependency.

See also: https://github.com/advisories/GHSA-pxg6-pf52-xh8x

• ws@~8.17.1 (no change)

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

• engine.io@~6.6.0 (diff and diff)
• ws@~8.17.1 (diff)

The transports option now accepts an array of transport implementations:

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

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

Here is the list of provided implementations:

Usage:

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

Added in f4d898e and b11763b.

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.

• 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)

• engine.io-client@~6.6.1 (diff and diff)
• ws@~8.17.1 (diff)

• discard all pending packets when the server is closed (923a12e)
• uws: prevent the client from upgrading twice (d5095fe)

• ws@~8.17.1 (no change)

• move 'offline' event listener at the top (8a2f5a3)
• only remove the event listener if it exists (9b3c9ab)
• do not send a packet on an expired connection (#5134) (8adcfbf)

• do not reset the heartbeat timer on each packet (7a23dde)

• ws@~8.17.1 (no change)

• do not expose the TransformStream type (f9cb983)

• add a noop handler for the error event (d30630b)

• Diff: https://github.com/socketio/socket.io/compare/2.5.0...2.5.1
• Client release: -
• engine.io version: ~3.6.0 (no change)
• ws version: ~7.5.10