Bug Fixes

• typings: ensure compatibility with TypeScript 3.x (#4259) (02c87a8)

Features

• add support for catch-all listeners for outgoing packets (531104d)

This is similar to onAny(), but for outgoing packets.

Syntax:

socket.onAnyOutgoing((event, ...args) => {
  console.log(event);
});

• broadcast and expect multiple acks (8b20457)

Syntax:

io.timeout(1000).emit("some-event", (err, responses) => {
  // ...
});

• add the "maxPayload" field in the handshake details (088dcb4)

So that clients in HTTP long-polling can decide how many packets they have to send to stay under the maxHttpBufferSize value.

This is a backward compatible change which should not mandate a new major revision of the protocol (we stay in v4), as we only add a field in the JSON-encoded handshake data:

0{"sid":"lv_VI97HAXpY6yYWAAAC","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":5000,"maxPayload":1000000}

Links:

• Diff: https://github.com/socketio/socket.io/compare/4.4.1...4.5.0
• Client release: 4.5.0
• engine.io version: ~6.2.0 (diff)
• ws version: ~8.2.3