socket.io 3.0.0

on Node.js NPM

More details about this release in the blog post: https://socket.io/blog/socket-io-3-release/

Dedicated migration guide: https://socket.io/docs/migrating-from-2-x-to-3-0/

Bug Fixes

• close clients with no namespace (91cd255)

Features

• emit an Error object upon middleware error (54bf4a4)
• serve msgpack bundle (aa7574f)
• add support for catch-all listeners (5c73733)
• make Socket#join() and Socket#leave() synchronous (129c641)
• remove prod dependency to socket.io-client (7603da7)
• move binary detection back to the parser (669592d)
• add ES6 module export (8b6b100)
• do not reuse the Engine.IO id (2875d2c)
• remove Server#set() method (029f478)
• remove Socket#rooms object (1507b41)
• remove the 'origins' option (a8c0600)
• remove the implicit connection to the default namespace (3289f7e)
• throw upon reserved event names (4bd5b23)

BREAKING CHANGES

• the Socket#use() method is removed (see 5c73733)

• Socket#join() and Socket#leave() do not accept a callback argument anymore.

Before:

socket.join("room1", () => {
 io.to("room1").emit("hello");
});

After:

socket.join("room1");
io.to("room1").emit("hello");
// or await socket.join("room1"); for custom adapters

• the "connected" map is renamed to "sockets"
• the Socket#binary() method is removed, as this use case is now covered by the ability to provide your own parser.
• the 'origins' option is removed

Before:

new Server(3000, {
  origins: ["https://example.com"]
});

The 'origins' option was used in the allowRequest method, in order to
determine whether the request should pass or not. And the Engine.IO
server would implicitly add the necessary Access-Control-Allow-xxx
headers.

After:

new Server(3000, {
  cors: {
    origin: "https://example.com",
    methods: ["GET", "POST"],
    allowedHeaders: ["content-type"]
  }
});

The already existing 'allowRequest' option can be used for validation:

new Server(3000, {
  allowRequest: (req, callback) => {
    callback(null, req.headers.referer.startsWith("https://example.com"));
  }
});

• Socket#rooms is now a Set instead of an object

• Namespace#connected is now a Map instead of an object

• there is no more implicit connection to the default namespace:

// client-side
const socket = io("/admin");

// server-side
io.on("connect", socket => {
  // not triggered anymore
})

io.use((socket, next) => {
  // not triggered anymore
});

io.of("/admin").use((socket, next) => {
  // triggered
});

• the Server#set() method was removed

This method was kept for backward-compatibility with pre-1.0 versions.

Links:

• Diff: 2.3.0...3.0.0
• Client release: 3.0.0
• engine.io version: ~4.0.0
• ws version: ^7.1.2