chore(release): 4.5.3

Diff: https://github.com/socketio/socket.io/compare/4.5.2...4.5.3

.github/workflows/ci.yml

@@ -6,21 +6,31 @@ on:
   schedule:
     - cron: '0 0 * * 0'
 
+permissions:
+  contents: read
+
 jobs:
   test-node:
     runs-on: ubuntu-latest
+    timeout-minutes: 10
 
     strategy:
       matrix:
         node-version: [12, 14, 16]
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v2
+        uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node-version }}
-      - run: npm ci
-      - run: npm test
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test
         env:
           CI: true

CHANGELOG.md

@@ -1,3 +1,54 @@
+# History
+
+- [4.5.3](#453-2022-10-15) (2022-10-15)
+- [4.5.2](#452-2022-09-02) (2022-09-02)
+- [4.5.1](#451-2022-05-17) (2022-05-17)
+- [4.5.0](#450-2022-04-23) (2022-04-23)
+- [4.4.1](#441-2022-01-06) (2022-01-06)
+- [4.4.0](#440-2021-11-18) (2021-11-18)
+- [4.3.2](#432-2021-11-08) (2021-11-08)
+- [4.3.1](#431-2021-10-16) (2021-10-16)
+- [4.3.0](#430-2021-10-14) (2021-10-14)
+- [4.2.0](#420-2021-08-30) (2021-08-30)
+- [4.1.3](#413-2021-07-10) (2021-07-10)
+- [4.1.2](#412-2021-05-17) (2021-05-17)
+- [4.1.1](#411-2021-05-11) (2021-05-11)
+- [4.1.0](#410-2021-05-11) (2021-05-11)
+- [4.0.2](#402-2021-05-06) (2021-05-06)
+- [4.0.1](#401-2021-03-31) (2021-03-31)
+- [4.0.0](#400-2021-03-10) (2021-03-10)
+- [3.1.2](#312-2021-02-26) (2021-02-26)
+- [3.1.1](#311-2021-02-03) (2021-02-03)
+- [3.1.0](#310-2021-01-15) (2021-01-15)
+- [3.0.5](#305-2021-01-05) (2021-01-05)
+- [3.0.4](#304-2020-12-07) (2020-12-07)
+- [3.0.3](#303-2020-11-19) (2020-11-19)
+- [3.0.2](#302-2020-11-17) (2020-11-17)
+- [3.0.1](#301-2020-11-09) (2020-11-09)
+- [3.0.0](#300-2020-11-05) (2020-11-05)
+
+# Release notes
+
+## [4.5.3](https://github.com/socketio/socket.io/compare/4.5.2...4.5.3) (2022-10-15)
+
+
+### Bug Fixes
+
+* **typings:** accept an HTTP2 server in the constructor ([d3d0a2d](https://github.com/socketio/socket.io/commit/d3d0a2d5beaff51fd145f810bcaf6914213f8a06))
+* **typings:** apply types to "io.timeout(...).emit()" calls ([e357daf](https://github.com/socketio/socket.io/commit/e357daf5858560bc84e7e50cd36f0278d6721ea1))
+
+
+
+## [4.5.2](https://github.com/socketio/socket.io/compare/4.5.1...4.5.2) (2022-09-02)
+
+
+### Bug Fixes
+
+* prevent the socket from joining a room after disconnection ([18f3fda](https://github.com/socketio/socket.io/commit/18f3fdab12947a9fee3e9c37cfc1da97027d1473))
+* **uws:** prevent the server from crashing after upgrade ([ba497ee](https://github.com/socketio/socket.io/commit/ba497ee3eb52c4abf1464380d015d8c788714364))
+
+
+
 ## [4.5.1](https://github.com/socketio/socket.io/compare/4.5.0...4.5.1) (2022-05-17)
 
 

client-dist/socket.io.js

@@ -1,5 +1,5 @@
 /*!
- * Socket.IO v4.5.1
+ * Socket.IO v4.5.3
  * (c) 2014-2022 Guillermo Rauch
  * Released under the MIT License.
  */
@@ -12,17 +12,11 @@
   function _typeof(obj) {
     "@babel/helpers - typeof";
 
-    if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") {
-      _typeof = function (obj) {
-        return typeof obj;
-      };
-    } else {
-      _typeof = function (obj) {
-        return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
-      };
-    }
-
-    return _typeof(obj);
+    return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (obj) {
+      return typeof obj;
+    } : function (obj) {
+      return obj && "function" == typeof Symbol && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
+    }, _typeof(obj);
   }
 
   function _classCallCheck(instance, Constructor) {
@@ -44,11 +38,14 @@
   function _createClass(Constructor, protoProps, staticProps) {
     if (protoProps) _defineProperties(Constructor.prototype, protoProps);
     if (staticProps) _defineProperties(Constructor, staticProps);
+    Object.defineProperty(Constructor, "prototype", {
+      writable: false
+    });
     return Constructor;
   }
 
   function _extends() {
-    _extends = Object.assign || function (target) {
+    _extends = Object.assign ? Object.assign.bind() : function (target) {
       for (var i = 1; i < arguments.length; i++) {
         var source = arguments[i];
 
@@ -61,7 +58,6 @@
 
       return target;
     };
-
     return _extends.apply(this, arguments);
   }
 
@@ -77,22 +73,24 @@
         configurable: true
       }
     });
+    Object.defineProperty(subClass, "prototype", {
+      writable: false
+    });
     if (superClass) _setPrototypeOf(subClass, superClass);
   }
 
   function _getPrototypeOf(o) {
-    _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) {
+    _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf.bind() : function _getPrototypeOf(o) {
       return o.__proto__ || Object.getPrototypeOf(o);
     };
     return _getPrototypeOf(o);
   }
 
   function _setPrototypeOf(o, p) {
-    _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) {
+    _setPrototypeOf = Object.setPrototypeOf ? Object.setPrototypeOf.bind() : function _setPrototypeOf(o, p) {
       o.__proto__ = p;
       return o;
     };
-
     return _setPrototypeOf(o, p);
   }
 
@@ -111,7 +109,7 @@
 
   function _construct(Parent, args, Class) {
     if (_isNativeReflectConstruct()) {
-      _construct = Reflect.construct;
+      _construct = Reflect.construct.bind();
     } else {
       _construct = function _construct(Parent, args, Class) {
         var a = [null];
@@ -210,9 +208,9 @@
     return object;
   }
 
-  function _get(target, property, receiver) {
+  function _get() {
     if (typeof Reflect !== "undefined" && Reflect.get) {
-      _get = Reflect.get;
+      _get = Reflect.get.bind();
     } else {
       _get = function _get(target, property, receiver) {
         var base = _superPropBase(target, property);
@@ -221,14 +219,14 @@
         var desc = Object.getOwnPropertyDescriptor(base, property);
 
         if (desc.get) {
-          return desc.get.call(receiver);
+          return desc.get.call(arguments.length < 3 ? target : receiver);
         }
 
         return desc.value;
       };
     }
 
-    return _get(target, property, receiver || target);
+    return _get.apply(this, arguments);
   }
 
   function _unsupportedIterableToArray(o, minLen) {
@@ -363,11 +361,6 @@
     return fileReader.readAsDataURL(data);
   };
 
-  /*
-   * base64-arraybuffer 1.0.1 <https://github.com/niklasvh/base64-arraybuffer>
-   * Copyright (c) 2022 Niklas von Hertzen <https://hertzen.com>
-   * Released under MIT License
-   */
   var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'; // Use a lookup table to find the index.
 
   var lookup$1 = typeof Uint8Array === 'undefined' ? [] : new Uint8Array(256);
@@ -375,7 +368,6 @@
   for (var i$1 = 0; i$1 < chars.length; i$1++) {
     lookup$1[chars.charCodeAt(i$1)] = i$1;
   }
-
   var decode$1 = function decode(base64) {
     var bufferLength = base64.length * 0.75,
         len = base64.length,
@@ -667,7 +659,7 @@
     return !!this.listeners(event).length;
   };
 
-  var globalThis = (function () {
+  var globalThisShim = function () {
     if (typeof self !== "undefined") {
       return self;
     } else if (typeof window !== "undefined") {
@@ -675,7 +667,7 @@
     } else {
       return Function("return this")();
     }
-  })();
+  }();
 
   function pick(obj) {
     for (var _len = arguments.length, attr = new Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
@@ -695,11 +687,11 @@
   var NATIVE_CLEAR_TIMEOUT = clearTimeout;
   function installTimerFunctions(obj, opts) {
     if (opts.useNativeTimers) {
-      obj.setTimeoutFn = NATIVE_SET_TIMEOUT.bind(globalThis);
-      obj.clearTimeoutFn = NATIVE_CLEAR_TIMEOUT.bind(globalThis);
+      obj.setTimeoutFn = NATIVE_SET_TIMEOUT.bind(globalThisShim);
+      obj.clearTimeoutFn = NATIVE_CLEAR_TIMEOUT.bind(globalThisShim);
     } else {
-      obj.setTimeoutFn = setTimeout.bind(globalThis);
-      obj.clearTimeoutFn = clearTimeout.bind(globalThis);
+      obj.setTimeoutFn = setTimeout.bind(globalThisShim);
+      obj.clearTimeoutFn = clearTimeout.bind(globalThisShim);
     }
   } // base64 encoded buffers are about 33% bigger (https://en.wikipedia.org/wiki/Base64)
 
@@ -753,7 +745,7 @@
       return _this;
     }
 
-    return TransportError;
+    return _createClass(TransportError);
   }( /*#__PURE__*/_wrapNativeSuper(Error));
 
   var Transport = /*#__PURE__*/function (_Emitter) {
@@ -998,7 +990,7 @@
   var hasCORS = value;
 
   // browser shim for xmlhttprequest module
-  function XMLHttpRequest$1 (opts) {
+  function XHR(opts) {
     var xdomain = opts.xdomain; // XMLHttpRequest can be disabled on IE
 
     try {
@@ -1009,7 +1001,7 @@
 
     if (!xdomain) {
       try {
-        return new globalThis[["Active"].concat("Object").join("X")]("Microsoft.XMLHTTP");
+        return new globalThisShim[["Active"].concat("Object").join("X")]("Microsoft.XMLHTTP");
       } catch (e) {}
     }
   }
@@ -1017,7 +1009,7 @@
   function empty() {}
 
   var hasXHR2 = function () {
-    var xhr = new XMLHttpRequest$1({
+    var xhr = new XHR({
       xdomain: false
     });
     return null != xhr.responseType;
@@ -1362,7 +1354,7 @@
         var opts = pick(this.opts, "agent", "pfx", "key", "passphrase", "cert", "ca", "ciphers", "rejectUnauthorized", "autoUnref");
         opts.xdomain = !!this.opts.xd;
         opts.xscheme = !!this.opts.xs;
-        var xhr = this.xhr = new XMLHttpRequest$1(opts);
+        var xhr = this.xhr = new XHR(opts);
 
         try {
           xhr.open(this.method, this.uri, this.async);
@@ -1513,7 +1505,7 @@
       // @ts-ignore
       attachEvent("onunload", unloadHandler);
     } else if (typeof addEventListener === "function") {
-      var terminationEvent = "onpagehide" in globalThis ? "pagehide" : "unload";
+      var terminationEvent = "onpagehide" in globalThisShim ? "pagehide" : "unload";
       addEventListener(terminationEvent, unloadHandler, false);
     }
   }
@@ -1539,7 +1531,7 @@
       };
     }
   }();
-  var WebSocket = globalThis.WebSocket || globalThis.MozWebSocket;
+  var WebSocket = globalThisShim.WebSocket || globalThisShim.MozWebSocket;
   var usingBrowserWebSocket = true;
   var defaultBinaryType = "arraybuffer";
 
@@ -1745,7 +1737,7 @@
     }, {
       key: "check",
       value: function check() {
-        return !!WebSocket && !("__initialize" in WebSocket && this.name === WS.prototype.name);
+        return !!WebSocket;
       }
     }]);
 
@@ -1800,11 +1792,11 @@
     var regx = /\/{2,9}/g,
         names = path.replace(regx, "/").split("/");
 
-    if (path.substr(0, 1) == '/' || path.length === 0) {
+    if (path.slice(0, 1) == '/' || path.length === 0) {
       names.splice(0, 1);
     }
 
-    if (path.substr(path.length - 1, 1) == '/') {
+    if (path.slice(-1) == '/') {
       names.splice(names.length - 1, 1);
     }
 
@@ -1904,14 +1896,16 @@
           // Firefox closes the connection when the "beforeunload" event is emitted but not Chrome. This event listener
           // ensures every browser behaves the same (no "disconnect" event at the Socket.IO level when the page is
           // closed/reloaded)
-          addEventListener("beforeunload", function () {
+          _this.beforeunloadEventListener = function () {
             if (_this.transport) {
               // silently close the transport
               _this.transport.removeAllListeners();
 
               _this.transport.close();
             }
-          }, false);
+          };
+
+          addEventListener("beforeunload", _this.beforeunloadEventListener, false);
         }
 
         if (_this.hostname !== "localhost") {
@@ -2459,6 +2453,7 @@
           this.transport.removeAllListeners();
 
           if (typeof removeEventListener === "function") {
+            removeEventListener("beforeunload", this.beforeunloadEventListener, false);
             removeEventListener("offline", this.offlineEventListener, false);
           } // set ready state
 
@@ -2501,6 +2496,8 @@
   }(Emitter);
   Socket$1.protocol = protocol$1;
 
+  Socket$1.protocol;
+
   /**
    * URL parser.
    *
@@ -3088,6 +3085,31 @@
     newListener: 1,
     removeListener: 1
   });
+  /**
+   * A Socket is the fundamental class for interacting with the server.
+   *
+   * A Socket belongs to a certain Namespace (by default /) and uses an underlying {@link Manager} to communicate.
+   *
+   * @example
+   * const socket = io();
+   *
+   * socket.on("connect", () => {
+   *   console.log("connected");
+   * });
+   *
+   * // send an event to the server
+   * socket.emit("foo", "bar");
+   *
+   * socket.on("foobar", () => {
+   *   // an event was received from the server
+   * });
+   *
+   * // upon disconnection
+   * socket.on("disconnect", (reason) => {
+   *   console.log(`disconnected due to ${reason}`);
+   * });
+   */
+
   var Socket = /*#__PURE__*/function (_Emitter) {
     _inherits(Socket, _Emitter);
 
@@ -3095,8 +3117,6 @@
 
     /**
      * `Socket` constructor.
-     *
-     * @public
      */
     function Socket(io, nsp, opts) {
       var _this;
@@ -3104,8 +3124,31 @@
       _classCallCheck(this, Socket);
 
       _this = _super.call(this);
+      /**
+       * Whether the socket is currently connected to the server.
+       *
+       * @example
+       * const socket = io();
+       *
+       * socket.on("connect", () => {
+       *   console.log(socket.connected); // true
+       * });
+       *
+       * socket.on("disconnect", () => {
+       *   console.log(socket.connected); // false
+       * });
+       */
+
       _this.connected = false;
+      /**
+       * Buffer for packets received before the CONNECT packet
+       */
+
       _this.receiveBuffer = [];
+      /**
+       * Buffer for packets that will be sent once the socket is connected
+       */
+
       _this.sendBuffer = [];
       _this.ids = 0;
       _this.acks = {};
@@ -3122,6 +3165,17 @@
     }
     /**
      * Whether the socket is currently disconnected
+     *
+     * @example
+     * const socket = io();
+     *
+     * socket.on("connect", () => {
+     *   console.log(socket.disconnected); // false
+     * });
+     *
+     * socket.on("disconnect", () => {
+     *   console.log(socket.disconnected); // true
+     * });
      */
 
 
@@ -3144,7 +3198,21 @@
         this.subs = [on(io, "open", this.onopen.bind(this)), on(io, "packet", this.onpacket.bind(this)), on(io, "error", this.onerror.bind(this)), on(io, "close", this.onclose.bind(this))];
       }
       /**
-       * Whether the Socket will try to reconnect when its Manager connects or reconnects
+       * Whether the Socket will try to reconnect when its Manager connects or reconnects.
+       *
+       * @example
+       * const socket = io();
+       *
+       * console.log(socket.active); // true
+       *
+       * socket.on("disconnect", (reason) => {
+       *   if (reason === "io server disconnect") {
+       *     // the disconnection was initiated by the server, you need to manually reconnect
+       *     console.log(socket.active); // false
+       *   }
+       *   // else the socket will automatically try to reconnect
+       *   console.log(socket.active); // true
+       * });
        */
 
     }, {
@@ -3155,7 +3223,12 @@
       /**
        * "Opens" the socket.
        *
-       * @public
+       * @example
+       * const socket = io({
+       *   autoConnect: false
+       * });
+       *
+       * socket.connect();
        */
 
     }, {
@@ -3169,7 +3242,7 @@
         return this;
       }
       /**
-       * Alias for connect()
+       * Alias for {@link connect()}.
        */
 
     }, {
@@ -3180,8 +3253,17 @@
       /**
        * Sends a `message` event.
        *
+       * This method mimics the WebSocket.send() method.
+       *
+       * @see https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/send
+       *
+       * @example
+       * socket.send("hello");
+       *
+       * // this is equivalent to
+       * socket.emit("message", "hello");
+       *
        * @return self
-       * @public
        */
 
     }, {
@@ -3199,15 +3281,25 @@
        * Override `emit`.
        * If the event is in `events`, it's emitted normally.
        *
+       * @example
+       * socket.emit("hello", "world");
+       *
+       * // all serializable datastructures are supported (no need to call JSON.stringify)
+       * socket.emit("hello", 1, "2", { 3: ["4"], 5: Uint8Array.from([6]) });
+       *
+       * // with an acknowledgement from the server
+       * socket.emit("hello", "world", (val) => {
+       *   // ...
+       * });
+       *
        * @return self
-       * @public
        */
 
     }, {
       key: "emit",
       value: function emit(ev) {
         if (RESERVED_EVENTS.hasOwnProperty(ev)) {
-          throw new Error('"' + ev + '" is a reserved event name');
+          throw new Error('"' + ev.toString() + '" is a reserved event name');
         }
 
         for (var _len2 = arguments.length, args = new Array(_len2 > 1 ? _len2 - 1 : 0), _key2 = 1; _key2 < _len2; _key2++) {
@@ -3558,10 +3650,20 @@
         this.io["_destroy"](this);
       }
       /**
-       * Disconnects the socket manually.
+       * Disconnects the socket manually. In that case, the socket will not try to reconnect.
+       *
+       * If this is the last active Socket instance of the {@link Manager}, the low-level connection will be closed.
+       *
+       * @example
+       * const socket = io();
+       *
+       * socket.on("disconnect", (reason) => {
+       *   // console.log(reason); prints "io client disconnect"
+       * });
+       *
+       * socket.disconnect();
        *
        * @return self
-       * @public
        */
 
     }, {
@@ -3584,10 +3686,9 @@
         return this;
       }
       /**
-       * Alias for disconnect()
+       * Alias for {@link disconnect()}.
        *
        * @return self
-       * @public
        */
 
     }, {
@@ -3598,9 +3699,11 @@
       /**
        * Sets the compress flag.
        *
+       * @example
+       * socket.compress(false).emit("hello");
+       *
        * @param compress - if `true`, compresses the sending data
        * @return self
-       * @public
        */
 
     }, {
@@ -3613,8 +3716,10 @@
        * Sets a modifier for a subsequent event emission that the event message will be dropped when this socket is not
        * ready to send messages.
        *
+       * @example
+       * socket.volatile.emit("hello"); // the server may or may not receive it
+       *
        * @returns self
-       * @public
        */
 
     }, {
@@ -3627,16 +3732,14 @@
        * Sets a modifier for a subsequent event emission that the callback will be called with an error when the
        * given number of milliseconds have elapsed without an acknowledgement from the server:
        *
-       * ```
+       * @example
        * socket.timeout(5000).emit("my-event", (err) => {
        *   if (err) {
        *     // the server did not acknowledge the event in the given delay
        *   }
        * });
-       * ```
        *
        * @returns self
-       * @public
        */
 
     }, {
@@ -3649,8 +3752,12 @@
        * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
        * callback.
        *
+       * @example
+       * socket.onAny((event, ...args) => {
+       *   console.log(`got ${event}`);
+       * });
+       *
        * @param listener
-       * @public
        */
 
     }, {
@@ -3666,8 +3773,12 @@
        * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
        * callback. The listener is added to the beginning of the listeners array.
        *
+       * @example
+       * socket.prependAny((event, ...args) => {
+       *   console.log(`got event ${event}`);
+       * });
+       *
        * @param listener
-       * @public
        */
 
     }, {
@@ -3682,8 +3793,20 @@
       /**
        * Removes the listener that will be fired when any event is emitted.
        *
+       * @example
+       * const catchAllListener = (event, ...args) => {
+       *   console.log(`got event ${event}`);
+       * }
+       *
+       * socket.onAny(catchAllListener);
+       *
+       * // remove a specific listener
+       * socket.offAny(catchAllListener);
+       *
+       * // or remove all listeners
+       * socket.offAny();
+       *
        * @param listener
-       * @public
        */
 
     }, {
@@ -3711,8 +3834,6 @@
       /**
        * Returns an array of listeners that are listening for any event that is specified. This array can be manipulated,
        * e.g. to remove listeners.
-       *
-       * @public
        */
 
     }, {
@@ -3724,17 +3845,14 @@
        * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
        * callback.
        *
-       * @param listener
-       *
-       * <pre><code>
+       * Note: acknowledgements sent to the server are not included.
        *
+       * @example
        * socket.onAnyOutgoing((event, ...args) => {
-       *   console.log(event);
+       *   console.log(`sent event ${event}`);
        * });
        *
-       * </pre></code>
-       *
-       * @public
+       * @param listener
        */
 
     }, {
@@ -3750,17 +3868,14 @@
        * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
        * callback. The listener is added to the beginning of the listeners array.
        *
-       * @param listener
-       *
-       * <pre><code>
+       * Note: acknowledgements sent to the server are not included.
        *
+       * @example
        * socket.prependAnyOutgoing((event, ...args) => {
-       *   console.log(event);
+       *   console.log(`sent event ${event}`);
        * });
        *
-       * </pre></code>
-       *
-       * @public
+       * @param listener
        */
 
     }, {
@@ -3775,22 +3890,20 @@
       /**
        * Removes the listener that will be fired when any event is emitted.
        *
-       * @param listener
-       *
-       * <pre><code>
-       *
-       * const handler = (event, ...args) => {
-       *   console.log(event);
+       * @example
+       * const catchAllListener = (event, ...args) => {
+       *   console.log(`sent event ${event}`);
        * }
        *
-       * socket.onAnyOutgoing(handler);
+       * socket.onAnyOutgoing(catchAllListener);
        *
-       * // then later
-       * socket.offAnyOutgoing(handler);
+       * // remove a specific listener
+       * socket.offAnyOutgoing(catchAllListener);
        *
-       * </pre></code>
+       * // or remove all listeners
+       * socket.offAnyOutgoing();
        *
-       * @public
+       * @param [listener] - the catch-all listener (optional)
        */
 
     }, {
@@ -3818,8 +3931,6 @@
       /**
        * Returns an array of listeners that are listening for any event that is specified. This array can be manipulated,
        * e.g. to remove listeners.
-       *
-       * @public
        */
 
     }, {
@@ -4179,7 +4290,11 @@
     }, {
       key: "ondata",
       value: function ondata(data) {
-        this.decoder.add(data);
+        try {
+          this.decoder.add(data);
+        } catch (e) {
+          this.onclose("parse error", e);
+        }
       }
       /**
        * Called when parser fully decodes a packet.
@@ -4190,7 +4305,12 @@
     }, {
       key: "ondecoded",
       value: function ondecoded(packet) {
-        this.emitReserved("packet", packet);
+        var _this3 = this;
+
+        // the nextTick call prevents an exception in a user-provided event listener from triggering a disconnection due to a "parse error"
+        nextTick(function () {
+          _this3.emitReserved("packet", packet);
+        }, this.setTimeoutFn);
       }
       /**
        * Called upon socket error.
@@ -4328,7 +4448,7 @@
     }, {
       key: "reconnect",
       value: function reconnect() {
-        var _this3 = this;
+        var _this4 = this;
 
         if (this._reconnecting || this.skipReconnect) return this;
         var self = this;
@@ -4343,7 +4463,7 @@
           var timer = this.setTimeoutFn(function () {
             if (self.skipReconnect) return;
 
-            _this3.emitReserved("reconnect_attempt", self.backoff.attempts); // check again for the case socket closed in above events
+            _this4.emitReserved("reconnect_attempt", self.backoff.attempts); // check again for the case socket closed in above events
 
 
             if (self.skipReconnect) return;
@@ -4352,7 +4472,7 @@
                 self._reconnecting = false;
                 self.reconnect();
 
-                _this3.emitReserved("reconnect_error", err);
+                _this4.emitReserved("reconnect_error", err);
               } else {
                 self.onreconnect();
               }

examples/basic-crud-application/server/package.json

@@ -24,14 +24,14 @@
     "uuid": "^8.3.2"
   },
   "devDependencies": {
-    "@types/mocha": "^8.2.3",
     "@types/chai": "^4.2.16",
+    "@types/mocha": "^10.0.0",
     "@types/uuid": "^8.3.0",
     "chai": "^4.3.4",
-    "mocha": "^8.3.2",
+    "mocha": "^10.0.0",
     "nyc": "^15.1.0",
     "socket.io-client": "^4.0.1",
-    "ts-node": "^9.1.1",
+    "ts-node": "^10.9.1",
     "typescript": "^4.2.4"
   }
 }

lib/broadcast-operator.ts

@@ -22,18 +22,27 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   /**
    * Targets a room when emitting.
    *
-   * @param room
-   * @return a new BroadcastOperator instance
-   * @public
+   * @example
+   * // the “foo” event will be broadcast to all connected clients in the “room-101” room
+   * io.to("room-101").emit("foo", "bar");
+   *
+   * // with an array of rooms (a client will be notified at most once)
+   * io.to(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   * // with multiple chained calls
+   * io.to("room-101").to("room-102").emit("foo", "bar");
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
+  public to(room: Room | Room[]) {
     const rooms = new Set(this.rooms);
     if (Array.isArray(room)) {
       room.forEach((r) => rooms.add(r));
     } else {
       rooms.add(room);
     }
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       rooms,
       this.exceptRooms,
@@ -42,33 +51,43 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   }
 
   /**
-   * Targets a room when emitting.
+   * Targets a room when emitting. Similar to `to()`, but might feel clearer in some cases:
    *
-   * @param room
-   * @return a new BroadcastOperator instance
-   * @public
+   * @example
+   * // disconnect all clients in the "room-101" room
+   * io.in("room-101").disconnectSockets();
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
+  public in(room: Room | Room[]) {
     return this.to(room);
   }
 
   /**
    * Excludes a room when emitting.
    *
-   * @param room
-   * @return a new BroadcastOperator instance
-   * @public
+   * @example
+   * // the "foo" event will be broadcast to all connected clients, except the ones that are in the "room-101" room
+   * io.except("room-101").emit("foo", "bar");
+   *
+   * // with an array of rooms
+   * io.except(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   * // with multiple chained calls
+   * io.except("room-101").except("room-102").emit("foo", "bar");
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public except(
-    room: Room | Room[]
-  ): BroadcastOperator<EmitEvents, SocketData> {
+  public except(room: Room | Room[]) {
     const exceptRooms = new Set(this.exceptRooms);
     if (Array.isArray(room)) {
       room.forEach((r) => exceptRooms.add(r));
     } else {
       exceptRooms.add(room);
     }
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       this.rooms,
       exceptRooms,
@@ -79,15 +98,15 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   /**
    * Sets the compress flag.
    *
+   * @example
+   * io.compress(false).emit("hello");
+   *
    * @param compress - if `true`, compresses the sending data
    * @return a new BroadcastOperator instance
-   * @public
    */
-  public compress(
-    compress: boolean
-  ): BroadcastOperator<EmitEvents, SocketData> {
+  public compress(compress: boolean) {
     const flags = Object.assign({}, this.flags, { compress });
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       this.rooms,
       this.exceptRooms,
@@ -100,12 +119,14 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
    * receive messages (because of network slowness or other issues, or because they’re connected through long polling
    * and is in the middle of a request-response cycle).
    *
+   * @example
+   * io.volatile.emit("hello"); // the clients may or may not receive it
+   *
    * @return a new BroadcastOperator instance
-   * @public
    */
-  public get volatile(): BroadcastOperator<EmitEvents, SocketData> {
+  public get volatile() {
     const flags = Object.assign({}, this.flags, { volatile: true });
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       this.rooms,
       this.exceptRooms,
@@ -116,12 +137,15 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   /**
    * Sets a modifier for a subsequent event emission that the event data will only be broadcast to the current node.
    *
-   * @return a new BroadcastOperator instance
-   * @public
+   * @example
+   * // the “foo” event will be broadcast to all connected clients on this node
+   * io.local.emit("foo", "bar");
+   *
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public get local(): BroadcastOperator<EmitEvents, SocketData> {
+  public get local() {
     const flags = Object.assign({}, this.flags, { local: true });
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       this.rooms,
       this.exceptRooms,
@@ -132,19 +156,20 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   /**
    * Adds a timeout in milliseconds for the next operation
    *
-   * <pre><code>
-   *
+   * @example
    * io.timeout(1000).emit("some-event", (err, responses) => {
-   *   // ...
+   *   if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
    * });
    *
-   * </pre></code>
-   *
    * @param timeout
    */
   public timeout(timeout: number) {
     const flags = Object.assign({}, this.flags, { timeout });
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       this.rooms,
       this.exceptRooms,
@@ -155,15 +180,30 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   /**
    * Emits to all clients.
    *
+   * @example
+   * // the “foo” event will be broadcast to all connected clients
+   * io.emit("foo", "bar");
+   *
+   * // the “foo” event will be broadcast to all connected clients in the “room-101” room
+   * io.to("room-101").emit("foo", "bar");
+   *
+   * // with an acknowledgement expected from all connected clients
+   * io.timeout(1000).emit("some-event", (err, responses) => {
+   *   if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
+   * });
+   *
    * @return Always true
-   * @public
    */
   public emit<Ev extends EventNames<EmitEvents>>(
     ev: Ev,
     ...args: EventParams<EmitEvents, Ev>
   ): boolean {
     if (RESERVED_EVENTS.has(ev)) {
-      throw new Error(`"${ev}" is a reserved event name`);
+      throw new Error(`"${String(ev)}" is a reserved event name`);
     }
     // set up packet object
     const data = [ev, ...args];
@@ -239,7 +279,8 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   /**
    * Gets a list of clients.
    *
-   * @public
+   * @deprecated this method will be removed in the next major release, please use {@link Server#serverSideEmit} or
+   * {@link fetchSockets} instead.
    */
   public allSockets(): Promise<Set<SocketId>> {
     if (!this.adapter) {
@@ -251,13 +292,30 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   }
 
   /**
-   * Returns the matching socket instances
+   * Returns the matching socket instances. This method works across a cluster of several Socket.IO servers.
    *
-   * @public
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * // return all Socket instances
+   * const sockets = await io.fetchSockets();
+   *
+   * // return all Socket instances in the "room1" room
+   * const sockets = await io.in("room1").fetchSockets();
+   *
+   * for (const socket of sockets) {
+   *   console.log(socket.id);
+   *   console.log(socket.handshake);
+   *   console.log(socket.rooms);
+   *   console.log(socket.data);
+   *
+   *   socket.emit("hello");
+   *   socket.join("room1");
+   *   socket.leave("room2");
+   *   socket.disconnect();
+   * }
    */
-  public fetchSockets<SocketData = any>(): Promise<
-    RemoteSocket<EmitEvents, SocketData>[]
-  > {
+  public fetchSockets(): Promise<RemoteSocket<EmitEvents, SocketData>[]> {
     return this.adapter
       .fetchSockets({
         rooms: this.rooms,
@@ -280,10 +338,19 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   }
 
   /**
-   * Makes the matching socket instances join the specified rooms
+   * Makes the matching socket instances join the specified rooms.
    *
-   * @param room
-   * @public
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   *
+   * // make all socket instances join the "room1" room
+   * io.socketsJoin("room1");
+   *
+   * // make all socket instances in the "room1" room join the "room2" and "room3" rooms
+   * io.in("room1").socketsJoin(["room2", "room3"]);
+   *
+   * @param room - a room, or an array of rooms
    */
   public socketsJoin(room: Room | Room[]): void {
     this.adapter.addSockets(
@@ -297,10 +364,18 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   }
 
   /**
-   * Makes the matching socket instances leave the specified rooms
+   * Makes the matching socket instances leave the specified rooms.
    *
-   * @param room
-   * @public
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * // make all socket instances leave the "room1" room
+   * io.socketsLeave("room1");
+   *
+   * // make all socket instances in the "room1" room leave the "room2" and "room3" rooms
+   * io.in("room1").socketsLeave(["room2", "room3"]);
+   *
+   * @param room - a room, or an array of rooms
    */
   public socketsLeave(room: Room | Room[]): void {
     this.adapter.delSockets(
@@ -314,10 +389,18 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   }
 
   /**
-   * Makes the matching socket instances disconnect
+   * Makes the matching socket instances disconnect.
+   *
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * // make all socket instances disconnect (the connections might be kept alive for other namespaces)
+   * io.disconnectSockets();
+   *
+   * // make all socket instances in the "room1" room disconnect and close the underlying connections
+   * io.in("room1").disconnectSockets(true);
    *
    * @param close - whether to close the underlying connection
-   * @public
    */
   public disconnectSockets(close: boolean = false): void {
     this.adapter.disconnectSockets(
@@ -359,7 +442,10 @@ export class RemoteSocket<EmitEvents extends EventsMap, SocketData>
     this.handshake = details.handshake;
     this.rooms = new Set(details.rooms);
     this.data = details.data;
-    this.operator = new BroadcastOperator(adapter, new Set([this.id]));
+    this.operator = new BroadcastOperator<EmitEvents, SocketData>(
+      adapter,
+      new Set([this.id])
+    );
   }
 
   public emit<Ev extends EventNames<EmitEvents>>(
@@ -373,7 +459,6 @@ export class RemoteSocket<EmitEvents extends EventsMap, SocketData>
    * Joins a room.
    *
    * @param {String|Array} room - room or array of rooms
-   * @public
    */
   public join(room: Room | Room[]): void {
     return this.operator.socketsJoin(room);
@@ -383,7 +468,6 @@ export class RemoteSocket<EmitEvents extends EventsMap, SocketData>
    * Leaves a room.
    *
    * @param {String} room
-   * @public
    */
   public leave(room: Room): void {
     return this.operator.socketsLeave(room);
@@ -394,8 +478,6 @@ export class RemoteSocket<EmitEvents extends EventsMap, SocketData>
    *
    * @param {Boolean} close - if `true`, closes the underlying connection
    * @return {Socket} self
-   *
-   * @public
    */
   public disconnect(close = false): this {
     this.operator.disconnectSockets(close);

lib/client.ts

@@ -18,6 +18,13 @@ interface WriteOptions {
   wsPreEncoded?: string;
 }
 
+type CloseReason =
+  | "transport error"
+  | "transport close"
+  | "forced close"
+  | "ping timeout"
+  | "parse error";
+
 export class Client<
   ListenEvents extends EventsMap,
   EmitEvents extends EventsMap,
@@ -306,7 +313,7 @@ export class Client<
    * @param reason
    * @private
    */
-  private onclose(reason: string): void {
+  private onclose(reason: CloseReason | "forced server close"): void {
     debug("client close with reason %s", reason);
 
     // ignore a potential subsequent `close` event

lib/index.ts

@@ -1,5 +1,6 @@
 import http = require("http");
 import type { Server as HTTPSServer } from "https";
+import type { Http2SecureServer } from "http2";
 import { createReadStream } from "fs";
 import { createDeflate, createGzip, createBrotliCompress } from "zlib";
 import accepts = require("accepts");
@@ -72,6 +73,32 @@ interface ServerOptions extends EngineOptions, AttachOptions {
   connectTimeout: number;
 }
 
+/**
+ * Represents a Socket.IO server.
+ *
+ * @example
+ * import { Server } from "socket.io";
+ *
+ * const io = new Server();
+ *
+ * io.on("connection", (socket) => {
+ *   console.log(`socket ${socket.id} connected`);
+ *
+ *   // send an event to the client
+ *   socket.emit("foo", "bar");
+ *
+ *   socket.on("foobar", () => {
+ *     // an event was received from the client
+ *   });
+ *
+ *   // upon disconnection
+ *   socket.on("disconnect", (reason) => {
+ *     console.log(`socket ${socket.id} disconnected due to ${reason}`);
+ *   });
+ * });
+ *
+ * io.listen(3000);
+ */
 export class Server<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
@@ -96,11 +123,8 @@ export class Server<
   /**
    * A reference to the underlying Engine.IO server.
    *
-   * Example:
-   *
-   * <code>
-   *   const clientsCount = io.engine.clientsCount;
-   * </code>
+   * @example
+   * const clientsCount = io.engine.clientsCount;
    *
    */
   public engine: any;
@@ -132,18 +156,17 @@ export class Server<
    * @private
    */
   _connectTimeout: number;
-  private httpServer: http.Server | HTTPSServer;
+  private httpServer: http.Server | HTTPSServer | Http2SecureServer;
 
   /**
    * Server constructor.
    *
    * @param srv http server, port, or options
    * @param [opts]
-   * @public
    */
   constructor(opts?: Partial<ServerOptions>);
   constructor(
-    srv?: http.Server | HTTPSServer | number,
+    srv?: http.Server | HTTPSServer | Http2SecureServer | number,
     opts?: Partial<ServerOptions>
   );
   constructor(
@@ -152,6 +175,7 @@ export class Server<
       | Partial<ServerOptions>
       | http.Server
       | HTTPSServer
+      | Http2SecureServer
       | number,
     opts?: Partial<ServerOptions>
   );
@@ -161,6 +185,7 @@ export class Server<
       | Partial<ServerOptions>
       | http.Server
       | HTTPSServer
+      | Http2SecureServer
       | number,
     opts: Partial<ServerOptions> = {}
   ) {
@@ -182,7 +207,9 @@ export class Server<
     this.sockets = this.of("/");
     this.opts = opts;
     if (srv || typeof srv == "number")
-      this.attach(srv as http.Server | HTTPSServer | number);
+      this.attach(
+        srv as http.Server | HTTPSServer | Http2SecureServer | number
+      );
   }
 
   /**
@@ -190,7 +217,6 @@ export class Server<
    *
    * @param v - whether to serve client code
    * @return self when setting or value when getting
-   * @public
    */
   public serveClient(v: boolean): this;
   public serveClient(): boolean;
@@ -253,7 +279,6 @@ export class Server<
    *
    * @param {String} v pathname
    * @return {Server|String} self when setting or value when getting
-   * @public
    */
   public path(v: string): this;
   public path(): string;
@@ -275,7 +300,6 @@ export class Server<
   /**
    * Set the delay after which a client without namespace is closed
    * @param v
-   * @public
    */
   public connectTimeout(v: number): this;
   public connectTimeout(): number;
@@ -291,7 +315,6 @@ export class Server<
    *
    * @param v pathname
    * @return self when setting or value when getting
-   * @public
    */
   public adapter(): AdapterConstructor | undefined;
   public adapter(v: AdapterConstructor): this;
@@ -312,10 +335,9 @@ export class Server<
    * @param srv - server or port
    * @param opts - options passed to engine.io
    * @return self
-   * @public
    */
   public listen(
-    srv: http.Server | HTTPSServer | number,
+    srv: http.Server | HTTPSServer | Http2SecureServer | number,
     opts: Partial<ServerOptions> = {}
   ): this {
     return this.attach(srv, opts);
@@ -327,10 +349,9 @@ export class Server<
    * @param srv - server or port
    * @param opts - options passed to engine.io
    * @return self
-   * @public
    */
   public attach(
-    srv: http.Server | HTTPSServer | number,
+    srv: http.Server | HTTPSServer | Http2SecureServer | number,
     opts: Partial<ServerOptions> = {}
   ): this {
     if ("function" == typeof srv) {
@@ -436,7 +457,7 @@ export class Server<
    * @private
    */
   private initEngine(
-    srv: http.Server | HTTPSServer,
+    srv: http.Server | HTTPSServer | Http2SecureServer,
     opts: EngineOptions & AttachOptions
   ): void {
     // initialize engine
@@ -459,7 +480,9 @@ export class Server<
    * @param srv http server
    * @private
    */
-  private attachServe(srv: http.Server | HTTPSServer): void {
+  private attachServe(
+    srv: http.Server | HTTPSServer | Http2SecureServer
+  ): void {
     debug("attaching client serving req handler");
 
     const evs = srv.listeners("request").slice(0);
@@ -561,7 +584,6 @@ export class Server<
    *
    * @param {engine.Server} engine engine.io (or compatible) server
    * @return self
-   * @public
    */
   public bind(engine): this {
     this.engine = engine;
@@ -589,9 +611,20 @@ export class Server<
   /**
    * Looks up a namespace.
    *
-   * @param {String|RegExp|Function} name nsp name
+   * @example
+   * // with a simple string
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // with a regex
+   * const dynamicNsp = io.of(/^\/dynamic-\d+$/).on("connection", (socket) => {
+   *   const namespace = socket.nsp; // newNamespace.name === "/dynamic-101"
+   *
+   *   // broadcast to all clients in the given sub-namespace
+   *   namespace.emit("hello");
+   * });
+   *
+   * @param name - nsp name
    * @param fn optional, nsp `connection` ev handler
-   * @public
    */
   public of(
     name: string | RegExp | ParentNspNameMatchFn,
@@ -637,7 +670,6 @@ export class Server<
    * Closes server connection
    *
    * @param [fn] optional, called as `fn([err])` on error OR all conns closed
-   * @public
    */
   public close(fn?: (err?: Error) => void): void {
     for (const socket of this.sockets.sockets.values()) {
@@ -657,10 +689,15 @@ export class Server<
   }
 
   /**
-   * Sets up namespace middleware.
+   * Registers a middleware, which is a function that gets executed for every incoming {@link Socket}.
    *
-   * @return self
-   * @public
+   * @example
+   * io.use((socket, next) => {
+   *   // ...
+   *   next();
+   * });
+   *
+   * @param fn - the middleware function
    */
   public use(
     fn: (
@@ -675,43 +712,71 @@ export class Server<
   /**
    * Targets a room when emitting.
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * // the “foo” event will be broadcast to all connected clients in the “room-101” room
+   * io.to("room-101").emit("foo", "bar");
+   *
+   * // with an array of rooms (a client will be notified at most once)
+   * io.to(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   * // with multiple chained calls
+   * io.to("room-101").to("room-102").emit("foo", "bar");
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
+  public to(room: Room | Room[]) {
     return this.sockets.to(room);
   }
 
   /**
-   * Targets a room when emitting.
+   * Targets a room when emitting. Similar to `to()`, but might feel clearer in some cases:
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * // disconnect all clients in the "room-101" room
+   * io.in("room-101").disconnectSockets();
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
+  public in(room: Room | Room[]) {
     return this.sockets.in(room);
   }
 
   /**
    * Excludes a room when emitting.
    *
-   * @param name
-   * @return self
-   * @public
+   * @example
+   * // the "foo" event will be broadcast to all connected clients, except the ones that are in the "room-101" room
+   * io.except("room-101").emit("foo", "bar");
+   *
+   * // with an array of rooms
+   * io.except(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   * // with multiple chained calls
+   * io.except("room-101").except("room-102").emit("foo", "bar");
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public except(
-    name: Room | Room[]
-  ): BroadcastOperator<EmitEvents, SocketData> {
-    return this.sockets.except(name);
+  public except(room: Room | Room[]) {
+    return this.sockets.except(room);
   }
 
   /**
    * Sends a `message` event to all clients.
    *
+   * This method mimics the WebSocket.send() method.
+   *
+   * @see https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/send
+   *
+   * @example
+   * io.send("hello");
+   *
+   * // this is equivalent to
+   * io.emit("message", "hello");
+   *
    * @return self
-   * @public
    */
   public send(...args: EventParams<EmitEvents, "message">): this {
     this.sockets.emit("message", ...args);
@@ -719,10 +784,9 @@ export class Server<
   }
 
   /**
-   * Sends a `message` event to all clients.
+   * Sends a `message` event to all clients. Alias of {@link send}.
    *
    * @return self
-   * @public
    */
   public write(...args: EventParams<EmitEvents, "message">): this {
     this.sockets.emit("message", ...args);
@@ -730,11 +794,30 @@ export class Server<
   }
 
   /**
-   * Emit a packet to other Socket.IO servers
+   * Sends a message to the other Socket.IO servers of the cluster.
+   *
+   * @example
+   * io.serverSideEmit("hello", "world");
+   *
+   * io.on("hello", (arg1) => {
+   *   console.log(arg1); // prints "world"
+   * });
+   *
+   * // acknowledgements (without binary content) are supported too:
+   * io.serverSideEmit("ping", (err, responses) => {
+   *  if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
+   * });
+   *
+   * io.on("ping", (cb) => {
+   *   cb("pong");
+   * });
    *
    * @param ev - the event name
    * @param args - an array of arguments, which may include an acknowledgement callback at the end
-   * @public
    */
   public serverSideEmit<Ev extends EventNames<ServerSideEvents>>(
     ev: Ev,
@@ -746,7 +829,8 @@ export class Server<
   /**
    * Gets a list of socket ids.
    *
-   * @public
+   * @deprecated this method will be removed in the next major release, please use {@link Server#serverSideEmit} or
+   * {@link Server#fetchSockets} instead.
    */
   public allSockets(): Promise<Set<SocketId>> {
     return this.sockets.allSockets();
@@ -755,13 +839,13 @@ export class Server<
   /**
    * Sets the compress flag.
    *
+   * @example
+   * io.compress(false).emit("hello");
+   *
    * @param compress - if `true`, compresses the sending data
-   * @return self
-   * @public
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public compress(
-    compress: boolean
-  ): BroadcastOperator<EmitEvents, SocketData> {
+  public compress(compress: boolean) {
     return this.sockets.compress(compress);
   }
 
@@ -770,34 +854,40 @@ export class Server<
    * receive messages (because of network slowness or other issues, or because they’re connected through long polling
    * and is in the middle of a request-response cycle).
    *
-   * @return self
-   * @public
+   * @example
+   * io.volatile.emit("hello"); // the clients may or may not receive it
+   *
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public get volatile(): BroadcastOperator<EmitEvents, SocketData> {
+  public get volatile() {
     return this.sockets.volatile;
   }
 
   /**
    * Sets a modifier for a subsequent event emission that the event data will only be broadcast to the current node.
    *
-   * @return self
-   * @public
+   * @example
+   * // the “foo” event will be broadcast to all connected clients on this node
+   * io.local.emit("foo", "bar");
+   *
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public get local(): BroadcastOperator<EmitEvents, SocketData> {
+  public get local() {
     return this.sockets.local;
   }
 
   /**
-   * Adds a timeout in milliseconds for the next operation
-   *
-   * <pre><code>
+   * Adds a timeout in milliseconds for the next operation.
    *
+   * @example
    * io.timeout(1000).emit("some-event", (err, responses) => {
-   *   // ...
+   *   if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
    * });
    *
-   * </pre></code>
-   *
    * @param timeout
    */
   public timeout(timeout: number) {
@@ -805,41 +895,85 @@ export class Server<
   }
 
   /**
-   * Returns the matching socket instances
+   * Returns the matching socket instances.
    *
-   * @public
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * // return all Socket instances
+   * const sockets = await io.fetchSockets();
+   *
+   * // return all Socket instances in the "room1" room
+   * const sockets = await io.in("room1").fetchSockets();
+   *
+   * for (const socket of sockets) {
+   *   console.log(socket.id);
+   *   console.log(socket.handshake);
+   *   console.log(socket.rooms);
+   *   console.log(socket.data);
+   *
+   *   socket.emit("hello");
+   *   socket.join("room1");
+   *   socket.leave("room2");
+   *   socket.disconnect();
+   * }
    */
   public fetchSockets(): Promise<RemoteSocket<EmitEvents, SocketData>[]> {
     return this.sockets.fetchSockets();
   }
 
   /**
-   * Makes the matching socket instances join the specified rooms
+   * Makes the matching socket instances join the specified rooms.
    *
-   * @param room
-   * @public
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   *
+   * // make all socket instances join the "room1" room
+   * io.socketsJoin("room1");
+   *
+   * // make all socket instances in the "room1" room join the "room2" and "room3" rooms
+   * io.in("room1").socketsJoin(["room2", "room3"]);
+   *
+   * @param room - a room, or an array of rooms
    */
-  public socketsJoin(room: Room | Room[]): void {
+  public socketsJoin(room: Room | Room[]) {
     return this.sockets.socketsJoin(room);
   }
 
   /**
-   * Makes the matching socket instances leave the specified rooms
+   * Makes the matching socket instances leave the specified rooms.
    *
-   * @param room
-   * @public
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * // make all socket instances leave the "room1" room
+   * io.socketsLeave("room1");
+   *
+   * // make all socket instances in the "room1" room leave the "room2" and "room3" rooms
+   * io.in("room1").socketsLeave(["room2", "room3"]);
+   *
+   * @param room - a room, or an array of rooms
    */
-  public socketsLeave(room: Room | Room[]): void {
+  public socketsLeave(room: Room | Room[]) {
     return this.sockets.socketsLeave(room);
   }
 
   /**
-   * Makes the matching socket instances disconnect
+   * Makes the matching socket instances disconnect.
+   *
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * // make all socket instances disconnect (the connections might be kept alive for other namespaces)
+   * io.disconnectSockets();
+   *
+   * // make all socket instances in the "room1" room disconnect and close the underlying connections
+   * io.in("room1").disconnectSockets(true);
    *
    * @param close - whether to close the underlying connection
-   * @public
    */
-  public disconnectSockets(close: boolean = false): void {
+  public disconnectSockets(close: boolean = false) {
     return this.sockets.disconnectSockets(close);
   }
 }

lib/namespace.ts

@@ -33,9 +33,9 @@ export interface NamespaceReservedEventsMap<
 }
 
 export interface ServerReservedEventsMap<
-  ListenEvents,
-  EmitEvents,
-  ServerSideEvents,
+  ListenEvents extends EventsMap,
+  EmitEvents extends EventsMap,
+  ServerSideEvents extends EventsMap,
   SocketData
 > extends NamespaceReservedEventsMap<
     ListenEvents,
@@ -52,6 +52,59 @@ export const RESERVED_EVENTS: ReadonlySet<string | Symbol> = new Set<
   keyof ServerReservedEventsMap<never, never, never, never>
 >(<const>["connect", "connection", "new_namespace"]);
 
+/**
+ * A Namespace is a communication channel that allows you to split the logic of your application over a single shared
+ * connection.
+ *
+ * Each namespace has its own:
+ *
+ * - event handlers
+ *
+ * ```
+ * io.of("/orders").on("connection", (socket) => {
+ *   socket.on("order:list", () => {});
+ *   socket.on("order:create", () => {});
+ * });
+ *
+ * io.of("/users").on("connection", (socket) => {
+ *   socket.on("user:list", () => {});
+ * });
+ * ```
+ *
+ * - rooms
+ *
+ * ```
+ * const orderNamespace = io.of("/orders");
+ *
+ * orderNamespace.on("connection", (socket) => {
+ *   socket.join("room1");
+ *   orderNamespace.to("room1").emit("hello");
+ * });
+ *
+ * const userNamespace = io.of("/users");
+ *
+ * userNamespace.on("connection", (socket) => {
+ *   socket.join("room1"); // distinct from the room in the "orders" namespace
+ *   userNamespace.to("room1").emit("holà");
+ * });
+ * ```
+ *
+ * - middlewares
+ *
+ * ```
+ * const orderNamespace = io.of("/orders");
+ *
+ * orderNamespace.use((socket, next) => {
+ *   // ensure the socket has access to the "orders" namespace
+ * });
+ *
+ * const userNamespace = io.of("/users");
+ *
+ * userNamespace.use((socket, next) => {
+ *   // ensure the socket has access to the "users" namespace
+ * });
+ * ```
+ */
 export class Namespace<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
@@ -123,10 +176,17 @@ export class Namespace<
   }
 
   /**
-   * Sets up namespace middleware.
+   * Registers a middleware, which is a function that gets executed for every incoming {@link Socket}.
    *
-   * @return self
-   * @public
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * myNamespace.use((socket, next) => {
+   *   // ...
+   *   next();
+   * });
+   *
+   * @param fn - the middleware function
    */
   public use(
     fn: (
@@ -171,36 +231,63 @@ export class Namespace<
   /**
    * Targets a room when emitting.
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // the “foo” event will be broadcast to all connected clients in the “room-101” room
+   * myNamespace.to("room-101").emit("foo", "bar");
+   *
+   * // with an array of rooms (a client will be notified at most once)
+   * myNamespace.to(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   * // with multiple chained calls
+   * myNamespace.to("room-101").to("room-102").emit("foo", "bar");
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
-    return new BroadcastOperator(this.adapter).to(room);
+  public to(room: Room | Room[]) {
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).to(room);
   }
 
   /**
-   * Targets a room when emitting.
+   * Targets a room when emitting. Similar to `to()`, but might feel clearer in some cases:
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // disconnect all clients in the "room-101" room
+   * myNamespace.in("room-101").disconnectSockets();
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
-    return new BroadcastOperator(this.adapter).in(room);
+  public in(room: Room | Room[]) {
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).in(room);
   }
 
   /**
    * Excludes a room when emitting.
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // the "foo" event will be broadcast to all connected clients, except the ones that are in the "room-101" room
+   * myNamespace.except("room-101").emit("foo", "bar");
+   *
+   * // with an array of rooms
+   * myNamespace.except(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   * // with multiple chained calls
+   * myNamespace.except("room-101").except("room-102").emit("foo", "bar");
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public except(
-    room: Room | Room[]
-  ): BroadcastOperator<EmitEvents, SocketData> {
-    return new BroadcastOperator(this.adapter).except(room);
+  public except(room: Room | Room[]) {
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).except(
+      room
+    );
   }
 
   /**
@@ -218,34 +305,38 @@ export class Namespace<
     const socket = new Socket(this, client, query);
     this.run(socket, (err) => {
       process.nextTick(() => {
-        if ("open" == client.conn.readyState) {
-          if (err) {
-            if (client.conn.protocol === 3) {
-              return socket._error(err.data || err.message);
-            } else {
-              return socket._error({
-                message: err.message,
-                data: err.data,
-              });
-            }
-          }
-
-          // track socket
-          this.sockets.set(socket.id, socket);
-
-          // it's paramount that the internal `onconnect` logic
-          // fires before user-set events to prevent state order
-          // violations (such as a disconnection before the connection
-          // logic is complete)
-          socket._onconnect();
-          if (fn) fn();
-
-          // fire user-set events
-          this.emitReserved("connect", socket);
-          this.emitReserved("connection", socket);
-        } else {
+        if ("open" !== client.conn.readyState) {
           debug("next called after client was closed - ignoring socket");
+          socket._cleanup();
+          return;
         }
+
+        if (err) {
+          debug("middleware error, sending CONNECT_ERROR packet to the client");
+          socket._cleanup();
+          if (client.conn.protocol === 3) {
+            return socket._error(err.data || err.message);
+          } else {
+            return socket._error({
+              message: err.message,
+              data: err.data,
+            });
+          }
+        }
+
+        // track socket
+        this.sockets.set(socket.id, socket);
+
+        // it's paramount that the internal `onconnect` logic
+        // fires before user-set events to prevent state order
+        // violations (such as a disconnection before the connection
+        // logic is complete)
+        socket._onconnect();
+        if (fn) fn();
+
+        // fire user-set events
+        this.emitReserved("connect", socket);
+        this.emitReserved("connection", socket);
       });
     });
     return socket;
@@ -267,10 +358,26 @@ export class Namespace<
   }
 
   /**
-   * Emits to all clients.
+   * Emits to all connected clients.
+   *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * myNamespace.emit("hello", "world");
+   *
+   * // all serializable datastructures are supported (no need to call JSON.stringify)
+   * myNamespace.emit("hello", 1, "2", { 3: ["4"], 5: Uint8Array.from([6]) });
+   *
+   * // with an acknowledgement from the clients
+   * myNamespace.timeout(1000).emit("some-event", (err, responses) => {
+   *   if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
+   * });
    *
    * @return Always true
-   * @public
    */
   public emit<Ev extends EventNames<EmitEvents>>(
     ev: Ev,
@@ -285,8 +392,19 @@ export class Namespace<
   /**
    * Sends a `message` event to all clients.
    *
+   * This method mimics the WebSocket.send() method.
+   *
+   * @see https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/send
+   *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * myNamespace.send("hello");
+   *
+   * // this is equivalent to
+   * myNamespace.emit("message", "hello");
+   *
    * @return self
-   * @public
    */
   public send(...args: EventParams<EmitEvents, "message">): this {
     this.emit("message", ...args);
@@ -294,10 +412,9 @@ export class Namespace<
   }
 
   /**
-   * Sends a `message` event to all clients.
+   * Sends a `message` event to all clients. Sends a `message` event. Alias of {@link send}.
    *
    * @return self
-   * @public
    */
   public write(...args: EventParams<EmitEvents, "message">): this {
     this.emit("message", ...args);
@@ -305,18 +422,39 @@ export class Namespace<
   }
 
   /**
-   * Emit a packet to other Socket.IO servers
+   * Sends a message to the other Socket.IO servers of the cluster.
+   *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * myNamespace.serverSideEmit("hello", "world");
+   *
+   * myNamespace.on("hello", (arg1) => {
+   *   console.log(arg1); // prints "world"
+   * });
+   *
+   * // acknowledgements (without binary content) are supported too:
+   * myNamespace.serverSideEmit("ping", (err, responses) => {
+   *  if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
+   * });
+   *
+   * myNamespace.on("ping", (cb) => {
+   *   cb("pong");
+   * });
    *
    * @param ev - the event name
    * @param args - an array of arguments, which may include an acknowledgement callback at the end
-   * @public
    */
   public serverSideEmit<Ev extends EventNames<ServerSideEvents>>(
     ev: Ev,
     ...args: EventParams<ServerSideEvents, Ev>
   ): boolean {
     if (RESERVED_EVENTS.has(ev)) {
-      throw new Error(`"${ev}" is a reserved event name`);
+      throw new Error(`"${String(ev)}" is a reserved event name`);
     }
     args.unshift(ev);
     this.adapter.serverSideEmit(args);
@@ -337,24 +475,30 @@ export class Namespace<
   /**
    * Gets a list of clients.
    *
-   * @return self
-   * @public
+   * @deprecated this method will be removed in the next major release, please use {@link Namespace#serverSideEmit} or
+   * {@link Namespace#fetchSockets} instead.
    */
   public allSockets(): Promise<Set<SocketId>> {
-    return new BroadcastOperator(this.adapter).allSockets();
+    return new BroadcastOperator<EmitEvents, SocketData>(
+      this.adapter
+    ).allSockets();
   }
 
   /**
    * Sets the compress flag.
    *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * myNamespace.compress(false).emit("hello");
+   *
    * @param compress - if `true`, compresses the sending data
    * @return self
-   * @public
    */
-  public compress(
-    compress: boolean
-  ): BroadcastOperator<EmitEvents, SocketData> {
-    return new BroadcastOperator(this.adapter).compress(compress);
+  public compress(compress: boolean) {
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).compress(
+      compress
+    );
   }
 
   /**
@@ -362,76 +506,149 @@ export class Namespace<
    * receive messages (because of network slowness or other issues, or because they’re connected through long polling
    * and is in the middle of a request-response cycle).
    *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * myNamespace.volatile.emit("hello"); // the clients may or may not receive it
+   *
    * @return self
-   * @public
    */
-  public get volatile(): BroadcastOperator<EmitEvents, SocketData> {
-    return new BroadcastOperator(this.adapter).volatile;
+  public get volatile() {
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).volatile;
   }
 
   /**
    * Sets a modifier for a subsequent event emission that the event data will only be broadcast to the current node.
    *
-   * @return self
-   * @public
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // the “foo” event will be broadcast to all connected clients on this node
+   * myNamespace.local.emit("foo", "bar");
+   *
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public get local(): BroadcastOperator<EmitEvents, SocketData> {
-    return new BroadcastOperator(this.adapter).local;
+  public get local() {
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).local;
   }
 
   /**
-   * Adds a timeout in milliseconds for the next operation
+   * Adds a timeout in milliseconds for the next operation.
    *
-   * <pre><code>
+   * @example
+   * const myNamespace = io.of("/my-namespace");
    *
-   * io.timeout(1000).emit("some-event", (err, responses) => {
-   *   // ...
+   * myNamespace.timeout(1000).emit("some-event", (err, responses) => {
+   *   if (err) {
+   *     // some clients did not acknowledge the event in the given delay
+   *   } else {
+   *     console.log(responses); // one response per client
+   *   }
    * });
    *
-   * </pre></code>
-   *
    * @param timeout
    */
   public timeout(timeout: number) {
-    return new BroadcastOperator(this.adapter).timeout(timeout);
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).timeout(
+      timeout
+    );
   }
 
   /**
-   * Returns the matching socket instances
+   * Returns the matching socket instances.
    *
-   * @public
-   */
-  public fetchSockets(): Promise<RemoteSocket<EmitEvents, SocketData>[]> {
-    return new BroadcastOperator(this.adapter).fetchSockets();
-  }
-
-  /**
-   * Makes the matching socket instances join the specified rooms
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
    *
-   * @param room
-   * @public
-   */
-  public socketsJoin(room: Room | Room[]): void {
-    return new BroadcastOperator(this.adapter).socketsJoin(room);
-  }
-
-  /**
-   * Makes the matching socket instances leave the specified rooms
+   * @example
+   * const myNamespace = io.of("/my-namespace");
    *
-   * @param room
-   * @public
+   * // return all Socket instances
+   * const sockets = await myNamespace.fetchSockets();
+   *
+   * // return all Socket instances in the "room1" room
+   * const sockets = await myNamespace.in("room1").fetchSockets();
+   *
+   * for (const socket of sockets) {
+   *   console.log(socket.id);
+   *   console.log(socket.handshake);
+   *   console.log(socket.rooms);
+   *   console.log(socket.data);
+   *
+   *   socket.emit("hello");
+   *   socket.join("room1");
+   *   socket.leave("room2");
+   *   socket.disconnect();
+   * }
    */
-  public socketsLeave(room: Room | Room[]): void {
-    return new BroadcastOperator(this.adapter).socketsLeave(room);
+  public fetchSockets() {
+    return new BroadcastOperator<EmitEvents, SocketData>(
+      this.adapter
+    ).fetchSockets();
   }
 
   /**
-   * Makes the matching socket instances disconnect
+   * Makes the matching socket instances join the specified rooms.
+   *
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // make all socket instances join the "room1" room
+   * myNamespace.socketsJoin("room1");
+   *
+   * // make all socket instances in the "room1" room join the "room2" and "room3" rooms
+   * myNamespace.in("room1").socketsJoin(["room2", "room3"]);
+   *
+   * @param room - a room, or an array of rooms
+   */
+  public socketsJoin(room: Room | Room[]) {
+    return new BroadcastOperator<EmitEvents, SocketData>(
+      this.adapter
+    ).socketsJoin(room);
+  }
+
+  /**
+   * Makes the matching socket instances leave the specified rooms.
+   *
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // make all socket instances leave the "room1" room
+   * myNamespace.socketsLeave("room1");
+   *
+   * // make all socket instances in the "room1" room leave the "room2" and "room3" rooms
+   * myNamespace.in("room1").socketsLeave(["room2", "room3"]);
+   *
+   * @param room - a room, or an array of rooms
+   */
+  public socketsLeave(room: Room | Room[]) {
+    return new BroadcastOperator<EmitEvents, SocketData>(
+      this.adapter
+    ).socketsLeave(room);
+  }
+
+  /**
+   * Makes the matching socket instances disconnect.
+   *
+   * Note: this method also works within a cluster of multiple Socket.IO servers, with a compatible {@link Adapter}.
+   *
+   * @example
+   * const myNamespace = io.of("/my-namespace");
+   *
+   * // make all socket instances disconnect (the connections might be kept alive for other namespaces)
+   * myNamespace.disconnectSockets();
+   *
+   * // make all socket instances in the "room1" room disconnect and close the underlying connections
+   * myNamespace.in("room1").disconnectSockets(true);
    *
    * @param close - whether to close the underlying connection
-   * @public
    */
-  public disconnectSockets(close: boolean = false): void {
-    return new BroadcastOperator(this.adapter).disconnectSockets(close);
+  public disconnectSockets(close: boolean = false) {
+    return new BroadcastOperator<EmitEvents, SocketData>(
+      this.adapter
+    ).disconnectSockets(close);
   }
 }

lib/socket.ts

@@ -25,9 +25,23 @@ const debug = debugModule("socket.io:socket");
 
 type ClientReservedEvents = "connect_error";
 
+// TODO for next major release: cleanup disconnect reasons
+export type DisconnectReason =
+  // Engine.IO close reasons
+  | "transport error"
+  | "transport close"
+  | "forced close"
+  | "ping timeout"
+  | "parse error"
+  // Socket.IO disconnect reasons
+  | "server shutting down"
+  | "forced server close"
+  | "client namespace disconnect"
+  | "server namespace disconnect";
+
 export interface SocketReservedEventsMap {
-  disconnect: (reason: string) => void;
-  disconnecting: (reason: string) => void;
+  disconnect: (reason: DisconnectReason) => void;
+  disconnecting: (reason: DisconnectReason) => void;
   error: (err: Error) => void;
 }
 
@@ -112,6 +126,39 @@ export interface Handshake {
  */
 export type Event = [string, ...any[]];
 
+function noop() {}
+
+/**
+ * This is the main object for interacting with a client.
+ *
+ * A Socket belongs to a given {@link Namespace} and uses an underlying {@link Client} to communicate.
+ *
+ * Within each {@link Namespace}, you can also define arbitrary channels (called "rooms") that the {@link Socket} can
+ * join and leave. That provides a convenient way to broadcast to a group of socket instances.
+ *
+ * @example
+ * io.on("connection", (socket) => {
+ *   console.log(`socket ${socket.id} connected`);
+ *
+ *   // send an event to the client
+ *   socket.emit("foo", "bar");
+ *
+ *   socket.on("foobar", () => {
+ *     // an event was received from the client
+ *   });
+ *
+ *   // join the room named "room1"
+ *   socket.join("room1");
+ *
+ *   // broadcast to everyone in the room named "room1"
+ *   io.to("room1").emit("hello");
+ *
+ *   // upon disconnection
+ *   socket.on("disconnect", (reason) => {
+ *     console.log(`socket ${socket.id} disconnected due to ${reason}`);
+ *   });
+ * });
+ */
 export class Socket<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
@@ -122,13 +169,32 @@ export class Socket<
   EmitEvents,
   SocketReservedEventsMap
 > {
+  /**
+   * An unique identifier for the session.
+   */
   public readonly id: SocketId;
+  /**
+   * The handshake details.
+   */
   public readonly handshake: Handshake;
   /**
-   * Additional information that can be attached to the Socket instance and which will be used in the fetchSockets method
+   * Additional information that can be attached to the Socket instance and which will be used in the
+   * {@link Server.fetchSockets()} method.
    */
   public data: Partial<SocketData> = {};
-
+  /**
+   * Whether the socket is currently connected or not.
+   *
+   * @example
+   * io.use((socket, next) => {
+   *   console.log(socket.connected); // false
+   *   next();
+   * });
+   *
+   * io.on("connection", (socket) => {
+   *   console.log(socket.connected); // true
+   * });
+   */
   public connected: boolean = false;
 
   private readonly server: Server<
@@ -193,15 +259,27 @@ export class Socket<
   /**
    * Emits to this client.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.emit("hello", "world");
+   *
+   *   // all serializable datastructures are supported (no need to call JSON.stringify)
+   *   socket.emit("hello", 1, "2", { 3: ["4"], 5: Buffer.from([6]) });
+   *
+   *   // with an acknowledgement from the client
+   *   socket.emit("hello", "world", (val) => {
+   *     // ...
+   *   });
+   * });
+   *
    * @return Always returns `true`.
-   * @public
    */
   public emit<Ev extends EventNames<EmitEvents>>(
     ev: Ev,
     ...args: EventParams<EmitEvents, Ev>
   ): boolean {
     if (RESERVED_EVENTS.has(ev)) {
-      throw new Error(`"${ev}" is a reserved event name`);
+      throw new Error(`"${String(ev)}" is a reserved event name`);
     }
     const data: any[] = [ev, ...args];
     const packet: any = {
@@ -252,43 +330,83 @@ export class Socket<
   /**
    * Targets a room when broadcasting.
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * io.on("connection", (socket) => {
+   *   // the “foo” event will be broadcast to all connected clients in the “room-101” room, except this socket
+   *   socket.to("room-101").emit("foo", "bar");
+   *
+   *   // the code above is equivalent to:
+   *   io.to("room-101").except(socket.id).emit("foo", "bar");
+   *
+   *   // with an array of rooms (a client will be notified at most once)
+   *   socket.to(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   *   // with multiple chained calls
+   *   socket.to("room-101").to("room-102").emit("foo", "bar");
+   * });
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
+  public to(room: Room | Room[]) {
     return this.newBroadcastOperator().to(room);
   }
 
   /**
-   * Targets a room when broadcasting.
+   * Targets a room when broadcasting. Similar to `to()`, but might feel clearer in some cases:
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * io.on("connection", (socket) => {
+   *   // disconnect all clients in the "room-101" room, except this socket
+   *   socket.in("room-101").disconnectSockets();
+   * });
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
+  public in(room: Room | Room[]) {
     return this.newBroadcastOperator().in(room);
   }
 
   /**
    * Excludes a room when broadcasting.
    *
-   * @param room
-   * @return self
-   * @public
+   * @example
+   * io.on("connection", (socket) => {
+   *   // the "foo" event will be broadcast to all connected clients, except the ones that are in the "room-101" room
+   *   // and this socket
+   *   socket.except("room-101").emit("foo", "bar");
+   *
+   *   // with an array of rooms
+   *   socket.except(["room-101", "room-102"]).emit("foo", "bar");
+   *
+   *   // with multiple chained calls
+   *   socket.except("room-101").except("room-102").emit("foo", "bar");
+   * });
+   *
+   * @param room - a room, or an array of rooms
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public except(
-    room: Room | Room[]
-  ): BroadcastOperator<EmitEvents, SocketData> {
+  public except(room: Room | Room[]) {
     return this.newBroadcastOperator().except(room);
   }
 
   /**
    * Sends a `message` event.
    *
+   * This method mimics the WebSocket.send() method.
+   *
+   * @see https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/send
+   *
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.send("hello");
+   *
+   *   // this is equivalent to
+   *   socket.emit("message", "hello");
+   * });
+   *
    * @return self
-   * @public
    */
   public send(...args: EventParams<EmitEvents, "message">): this {
     this.emit("message", ...args);
@@ -296,10 +414,9 @@ export class Socket<
   }
 
   /**
-   * Sends a `message` event.
+   * Sends a `message` event. Alias of {@link send}.
    *
    * @return self
-   * @public
    */
   public write(...args: EventParams<EmitEvents, "message">): this {
     this.emit("message", ...args);
@@ -325,9 +442,17 @@ export class Socket<
   /**
    * Joins a room.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   // join a single room
+   *   socket.join("room1");
+   *
+   *   // join multiple rooms
+   *   socket.join(["room1", "room2"]);
+   * });
+   *
    * @param {String|Array} rooms - room or array of rooms
    * @return a Promise or nothing, depending on the adapter
-   * @public
    */
   public join(rooms: Room | Array<Room>): Promise<void> | void {
     debug("join room %s", rooms);
@@ -341,9 +466,17 @@ export class Socket<
   /**
    * Leaves a room.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   // leave a single room
+   *   socket.leave("room1");
+   *
+   *   // leave multiple rooms
+   *   socket.leave("room1").leave("room2");
+   * });
+   *
    * @param {String} room
    * @return a Promise or nothing, depending on the adapter
-   * @public
    */
   public leave(room: string): Promise<void> | void {
     debug("leave room %s", room);
@@ -507,11 +640,11 @@ export class Socket<
    *
    * @private
    */
-  _onclose(reason: string): this | undefined {
+  _onclose(reason: DisconnectReason): this | undefined {
     if (!this.connected) return this;
     debug("closing socket - reason %s", reason);
     this.emitReserved("disconnecting", reason);
-    this.leaveAll();
+    this._cleanup();
     this.nsp._remove(this);
     this.client._remove(this);
     this.connected = false;
@@ -519,6 +652,16 @@ export class Socket<
     return;
   }
 
+  /**
+   * Makes the socket leave all the rooms it was part of and prevents it from joining any other room
+   *
+   * @private
+   */
+  _cleanup() {
+    this.leaveAll();
+    this.join = noop;
+  }
+
   /**
    * Produces an `error` packet.
    *
@@ -533,10 +676,17 @@ export class Socket<
   /**
    * Disconnects this client.
    *
-   * @param {Boolean} close - if `true`, closes the underlying connection
-   * @return {Socket} self
+   * @example
+   * io.on("connection", (socket) => {
+   *   // disconnect this socket (the connection might be kept alive for other namespaces)
+   *   socket.disconnect();
    *
-   * @public
+   *   // disconnect this socket and close the underlying connection
+   *   socket.disconnect(true);
+   * })
+   *
+   * @param {Boolean} close - if `true`, closes the underlying connection
+   * @return self
    */
   public disconnect(close = false): this {
     if (!this.connected) return this;
@@ -552,9 +702,13 @@ export class Socket<
   /**
    * Sets the compress flag.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.compress(false).emit("hello");
+   * });
+   *
    * @param {Boolean} compress - if `true`, compresses the sending data
    * @return {Socket} self
-   * @public
    */
   public compress(compress: boolean): this {
     this.flags.compress = compress;
@@ -566,8 +720,12 @@ export class Socket<
    * receive messages (because of network slowness or other issues, or because they’re connected through long polling
    * and is in the middle of a request-response cycle).
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.volatile.emit("hello"); // the client may or may not receive it
+   * });
+   *
    * @return {Socket} self
-   * @public
    */
   public get volatile(): this {
     this.flags.volatile = true;
@@ -578,20 +736,30 @@ export class Socket<
    * Sets a modifier for a subsequent event emission that the event data will only be broadcast to every sockets but the
    * sender.
    *
-   * @return {Socket} self
-   * @public
+   * @example
+   * io.on("connection", (socket) => {
+   *   // the “foo” event will be broadcast to all connected clients, except this socket
+   *   socket.broadcast.emit("foo", "bar");
+   * });
+   *
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public get broadcast(): BroadcastOperator<EmitEvents, SocketData> {
+  public get broadcast() {
     return this.newBroadcastOperator();
   }
 
   /**
    * Sets a modifier for a subsequent event emission that the event data will only be broadcast to the current node.
    *
-   * @return {Socket} self
-   * @public
+   * @example
+   * io.on("connection", (socket) => {
+   *   // the “foo” event will be broadcast to all connected clients on this node, except this socket
+   *   socket.local.emit("foo", "bar");
+   * });
+   *
+   * @return a new {@link BroadcastOperator} instance for chaining
    */
-  public get local(): BroadcastOperator<EmitEvents, SocketData> {
+  public get local() {
     return this.newBroadcastOperator().local;
   }
 
@@ -599,16 +767,16 @@ export class Socket<
    * Sets a modifier for a subsequent event emission that the callback will be called with an error when the
    * given number of milliseconds have elapsed without an acknowledgement from the client:
    *
-   * ```
-   * socket.timeout(5000).emit("my-event", (err) => {
-   *   if (err) {
-   *     // the client did not acknowledge the event in the given delay
-   *   }
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.timeout(5000).emit("my-event", (err) => {
+   *     if (err) {
+   *       // the client did not acknowledge the event in the given delay
+   *     }
+   *   });
    * });
-   * ```
    *
    * @returns self
-   * @public
    */
   public timeout(timeout: number): this {
     this.flags.timeout = timeout;
@@ -640,9 +808,25 @@ export class Socket<
   /**
    * Sets up socket middleware.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.use(([event, ...args], next) => {
+   *     if (isUnauthorized(event)) {
+   *       return next(new Error("unauthorized event"));
+   *     }
+   *     // do not forget to call next
+   *     next();
+   *   });
+   *
+   *   socket.on("error", (err) => {
+   *     if (err && err.message === "unauthorized event") {
+   *       socket.disconnect();
+   *     }
+   *   });
+   * });
+   *
    * @param {Function} fn - middleware function (event, next)
    * @return {Socket} self
-   * @public
    */
   public use(fn: (event: Event, next: (err?: Error) => void) => void): this {
     this.fns.push(fn);
@@ -685,8 +869,6 @@ export class Socket<
 
   /**
    * A reference to the request that originated the underlying Engine.IO Socket.
-   *
-   * @public
    */
   public get request(): IncomingMessage {
     return this.client.request;
@@ -695,14 +877,30 @@ export class Socket<
   /**
    * A reference to the underlying Client transport connection (Engine.IO Socket object).
    *
-   * @public
+   * @example
+   * io.on("connection", (socket) => {
+   *   console.log(socket.conn.transport.name); // prints "polling" or "websocket"
+   *
+   *   socket.conn.once("upgrade", () => {
+   *     console.log(socket.conn.transport.name); // prints "websocket"
+   *   });
+   * });
    */
   public get conn() {
     return this.client.conn;
   }
 
   /**
-   * @public
+   * Returns the rooms the socket is currently in.
+   *
+   * @example
+   * io.on("connection", (socket) => {
+   *   console.log(socket.rooms); // Set { <socket.id> }
+   *
+   *   socket.join("room1");
+   *
+   *   console.log(socket.rooms); // Set { <socket.id>, "room1" }
+   * });
    */
   public get rooms(): Set<Room> {
     return this.adapter.socketRooms(this.id) || new Set();
@@ -712,8 +910,14 @@ export class Socket<
    * Adds a listener that will be fired when any event is received. The event name is passed as the first argument to
    * the callback.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.onAny((event, ...args) => {
+   *     console.log(`got event ${event}`);
+   *   });
+   * });
+   *
    * @param listener
-   * @public
    */
   public onAny(listener: (...args: any[]) => void): this {
     this._anyListeners = this._anyListeners || [];
@@ -726,7 +930,6 @@ export class Socket<
    * the callback. The listener is added to the beginning of the listeners array.
    *
    * @param listener
-   * @public
    */
   public prependAny(listener: (...args: any[]) => void): this {
     this._anyListeners = this._anyListeners || [];
@@ -737,8 +940,22 @@ export class Socket<
   /**
    * Removes the listener that will be fired when any event is received.
    *
+   * @example
+   * io.on("connection", (socket) => {
+   *   const catchAllListener = (event, ...args) => {
+   *     console.log(`got event ${event}`);
+   *   }
+   *
+   *   socket.onAny(catchAllListener);
+   *
+   *   // remove a specific listener
+   *   socket.offAny(catchAllListener);
+   *
+   *   // or remove all listeners
+   *   socket.offAny();
+   * });
+   *
    * @param listener
-   * @public
    */
   public offAny(listener?: (...args: any[]) => void): this {
     if (!this._anyListeners) {
@@ -761,28 +978,25 @@ export class Socket<
   /**
    * Returns an array of listeners that are listening for any event that is specified. This array can be manipulated,
    * e.g. to remove listeners.
-   *
-   * @public
    */
   public listenersAny() {
     return this._anyListeners || [];
   }
 
   /**
-   * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
-   * callback.
+   * Adds a listener that will be fired when any event is sent. The event name is passed as the first argument to
+   * the callback.
    *
-   * @param listener
+   * Note: acknowledgements sent to the client are not included.
    *
-   * <pre><code>
-   *
-   * socket.onAnyOutgoing((event, ...args) => {
-   *   console.log(event);
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.onAnyOutgoing((event, ...args) => {
+   *     console.log(`sent event ${event}`);
+   *   });
    * });
    *
-   * </pre></code>
-   *
-   * @public
+   * @param listener
    */
   public onAnyOutgoing(listener: (...args: any[]) => void): this {
     this._anyOutgoingListeners = this._anyOutgoingListeners || [];
@@ -794,17 +1008,14 @@ export class Socket<
    * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
    * callback. The listener is added to the beginning of the listeners array.
    *
-   * @param listener
-   *
-   * <pre><code>
-   *
-   * socket.prependAnyOutgoing((event, ...args) => {
-   *   console.log(event);
+   * @example
+   * io.on("connection", (socket) => {
+   *   socket.prependAnyOutgoing((event, ...args) => {
+   *     console.log(`sent event ${event}`);
+   *   });
    * });
    *
-   * </pre></code>
-   *
-   * @public
+   * @param listener
    */
   public prependAnyOutgoing(listener: (...args: any[]) => void): this {
     this._anyOutgoingListeners = this._anyOutgoingListeners || [];
@@ -813,24 +1024,24 @@ export class Socket<
   }
 
   /**
-   * Removes the listener that will be fired when any event is emitted.
+   * Removes the listener that will be fired when any event is sent.
    *
-   * @param listener
+   * @example
+   * io.on("connection", (socket) => {
+   *   const catchAllListener = (event, ...args) => {
+   *     console.log(`sent event ${event}`);
+   *   }
    *
-   * <pre><code>
+   *   socket.onAnyOutgoing(catchAllListener);
    *
-   * const handler = (event, ...args) => {
-   *   console.log(event);
-   * }
+   *   // remove a specific listener
+   *   socket.offAnyOutgoing(catchAllListener);
    *
-   * socket.onAnyOutgoing(handler);
+   *   // or remove all listeners
+   *   socket.offAnyOutgoing();
+   * });
    *
-   * // then later
-   * socket.offAnyOutgoing(handler);
-   *
-   * </pre></code>
-   *
-   * @public
+   * @param listener - the catch-all listener
    */
   public offAnyOutgoing(listener?: (...args: any[]) => void): this {
     if (!this._anyOutgoingListeners) {
@@ -853,8 +1064,6 @@ export class Socket<
   /**
    * Returns an array of listeners that are listening for any event that is specified. This array can be manipulated,
    * e.g. to remove listeners.
-   *
-   * @public
    */
   public listenersAnyOutgoing() {
     return this._anyOutgoingListeners || [];
@@ -876,10 +1085,10 @@ export class Socket<
     }
   }
 
-  private newBroadcastOperator(): BroadcastOperator<EmitEvents, SocketData> {
+  private newBroadcastOperator() {
     const flags = Object.assign({}, this.flags);
     this.flags = {};
-    return new BroadcastOperator(
+    return new BroadcastOperator<EmitEvents, SocketData>(
       this.adapter,
       new Set<Room>(),
       new Set<Room>([this.id]),

lib/uws.ts

@@ -25,7 +25,9 @@ export function patchAdapter(app /* : TemplatedApp */) {
     if (isNew) {
       socket.conn.on("upgrade", () => {
         const rooms = this.sids.get(id);
-        subscribe(this.nsp.name, socket, isNew, rooms);
+        if (rooms) {
+          subscribe(this.nsp.name, socket, isNew, rooms);
+        }
       });
     }
   };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "socket.io",
-  "version": "4.5.1",
+  "version": "4.5.3",
   "description": "node.js realtime framework server",
   "keywords": [
     "realtime",
@@ -40,7 +40,7 @@
     "compile": "rimraf ./dist && tsc",
     "test": "npm run format:check && npm run compile && npm run test:types && npm run test:unit",
     "test:types": "tsd",
-    "test:unit": "nyc mocha --require ts-node/register --reporter spec --slow 200 --bail --timeout 10000 test/socket.io.ts",
+    "test:unit": "nyc mocha --require ts-node/register --reporter spec --slow 200 --bail --timeout 10000 test/index.ts",
     "format:check": "prettier --check \"lib/**/*.ts\" \"test/**/*.ts\"",
     "format:fix": "prettier --write \"lib/**/*.ts\" \"test/**/*.ts\"",
     "prepack": "npm run compile"
@@ -51,21 +51,21 @@
     "debug": "~4.3.2",
     "engine.io": "~6.2.0",
     "socket.io-adapter": "~2.4.0",
-    "socket.io-parser": "~4.0.4"
+    "socket.io-parser": "~4.2.0"
   },
   "devDependencies": {
     "@types/mocha": "^9.0.0",
     "expect.js": "0.3.1",
-    "mocha": "^3.5.3",
+    "mocha": "^10.0.0",
     "nyc": "^15.1.0",
     "prettier": "^2.3.2",
     "rimraf": "^3.0.2",
-    "socket.io-client": "4.5.1",
+    "socket.io-client": "4.5.3",
     "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
-    "superagent": "^6.1.0",
+    "superagent": "^8.0.0",
     "supertest": "^6.1.6",
     "ts-node": "^10.2.1",
-    "tsd": "^0.17.0",
+    "tsd": "^0.21.0",
     "typescript": "^4.4.2",
     "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.0.0"
   },

test/close.ts

@@ -0,0 +1,181 @@
+import { createServer } from "http";
+import { io as ioc } from "socket.io-client";
+import { join } from "path";
+import { exec } from "child_process";
+import { Server } from "..";
+import expect from "expect.js";
+import { createClient, getPort } from "./support/util";
+import request from "supertest";
+
+// TODO: update superagent as latest release now supports promises
+const eioHandshake = (httpServer): Promise<string> => {
+  return new Promise((resolve) => {
+    request(httpServer)
+      .get("/socket.io/")
+      .query({ transport: "polling", EIO: 4 })
+      .end((err, res) => {
+        const sid = JSON.parse(res.text.substring(1)).sid;
+        resolve(sid);
+      });
+  });
+};
+
+const eioPush = (httpServer, sid: string, body: string): Promise<void> => {
+  return new Promise((resolve) => {
+    request(httpServer)
+      .post("/socket.io/")
+      .send(body)
+      .query({ transport: "polling", EIO: 4, sid })
+      .expect(200)
+      .end(() => {
+        resolve();
+      });
+  });
+};
+
+const eioPoll = (httpServer, sid): Promise<string> => {
+  return new Promise((resolve) => {
+    request(httpServer)
+      .get("/socket.io/")
+      .query({ transport: "polling", EIO: 4, sid })
+      .expect(200)
+      .end((err, res) => {
+        resolve(res.text);
+      });
+  });
+};
+
+describe("close", () => {
+  it("should be able to close sio sending a srv", (done) => {
+    const httpServer = createServer().listen(0);
+    const io = new Server(httpServer);
+    const port = getPort(io);
+    const net = require("net");
+    const server = net.createServer();
+
+    const clientSocket = createClient(io, "/", { reconnection: false });
+
+    clientSocket.on("disconnect", () => {
+      expect(io.sockets.sockets.size).to.equal(0);
+      server.listen(port);
+    });
+
+    clientSocket.on("connect", () => {
+      expect(io.sockets.sockets.size).to.equal(1);
+      io.close();
+    });
+
+    server.once("listening", () => {
+      // PORT should be free
+      server.close((error) => {
+        expect(error).to.be(undefined);
+        done();
+      });
+    });
+  });
+
+  it("should be able to close sio sending a srv", (done) => {
+    const io = new Server(0);
+    const port = getPort(io);
+    const net = require("net");
+    const server = net.createServer();
+
+    const clientSocket = ioc("ws://0.0.0.0:" + port, {
+      reconnection: false,
+    });
+
+    clientSocket.on("disconnect", () => {
+      expect(io.sockets.sockets.size).to.equal(0);
+      server.listen(port);
+    });
+
+    clientSocket.on("connect", () => {
+      expect(io.sockets.sockets.size).to.equal(1);
+      io.close();
+    });
+
+    server.once("listening", () => {
+      // PORT should be free
+      server.close((error) => {
+        expect(error).to.be(undefined);
+        done();
+      });
+    });
+  });
+
+  describe("graceful close", () => {
+    function fixture(filename) {
+      return (
+        '"' +
+        process.execPath +
+        '" "' +
+        join(__dirname, "fixtures", filename) +
+        '"'
+      );
+    }
+
+    it("should stop socket and timers", (done) => {
+      exec(fixture("server-close.ts"), done);
+    });
+  });
+
+  describe("protocol violations", () => {
+    it("should close the connection when receiving several CONNECT packets", async () => {
+      const httpServer = createServer();
+      const io = new Server(httpServer);
+
+      httpServer.listen(0);
+
+      const sid = await eioHandshake(httpServer);
+      // send a first CONNECT packet
+      await eioPush(httpServer, sid, "40");
+      // send another CONNECT packet
+      await eioPush(httpServer, sid, "40");
+      // session is cleanly closed (not discarded, see 'client.close()')
+      // first, we receive the Socket.IO handshake response
+      await eioPoll(httpServer, sid);
+      // then a close packet
+      const body = await eioPoll(httpServer, sid);
+      expect(body).to.be("6\u001e1");
+
+      io.close();
+    });
+
+    it("should close the connection when receiving an EVENT packet while not connected", async () => {
+      const httpServer = createServer();
+      const io = new Server(httpServer);
+
+      httpServer.listen(0);
+
+      const sid = await eioHandshake(httpServer);
+      // send an EVENT packet
+      await eioPush(httpServer, sid, '42["some event"]');
+      // session is cleanly closed, we receive a close packet
+      const body = await eioPoll(httpServer, sid);
+      expect(body).to.be("6\u001e1");
+
+      io.close();
+    });
+
+    it("should close the connection when receiving an invalid packet", async () => {
+      const httpServer = createServer();
+      const io = new Server(httpServer);
+
+      httpServer.listen(0);
+
+      const sid = await eioHandshake(httpServer);
+      // send a CONNECT packet
+      await eioPush(httpServer, sid, "40");
+      // send an invalid packet
+      await eioPush(httpServer, sid, "4abc");
+      // session is cleanly closed (not discarded, see 'client.close()')
+      // first, we receive the Socket.IO handshake response
+      await eioPoll(httpServer, sid);
+      // then a close packet
+      const body = await eioPoll(httpServer, sid);
+      expect(body).to.be("6\u001e1");
+
+      io.close();
+    });
+  });
+});

test/handshake.ts

@@ -0,0 +1,87 @@
+import { Server } from "..";
+import expect from "expect.js";
+import { getPort, success } from "./support/util";
+
+describe("handshake", () => {
+  const request = require("superagent");
+
+  it("should send the Access-Control-Allow-xxx headers on OPTIONS request", (done) => {
+    const io = new Server(0, {
+      cors: {
+        origin: "http://localhost:54023",
+        methods: ["GET", "POST"],
+        allowedHeaders: ["content-type"],
+        credentials: true,
+      },
+    });
+    request
+      .options(`http://localhost:${getPort(io)}/socket.io/default/`)
+      .query({ transport: "polling", EIO: 4 })
+      .set("Origin", "http://localhost:54023")
+      .end((err, res) => {
+        expect(res.status).to.be(204);
+
+        expect(res.headers["access-control-allow-origin"]).to.be(
+          "http://localhost:54023"
+        );
+        expect(res.headers["access-control-allow-methods"]).to.be("GET,POST");
+        expect(res.headers["access-control-allow-headers"]).to.be(
+          "content-type"
+        );
+        expect(res.headers["access-control-allow-credentials"]).to.be("true");
+        success(done, io);
+      });
+  });
+
+  it("should send the Access-Control-Allow-xxx headers on GET request", (done) => {
+    const io = new Server(0, {
+      cors: {
+        origin: "http://localhost:54024",
+        methods: ["GET", "POST"],
+        allowedHeaders: ["content-type"],
+        credentials: true,
+      },
+    });
+    request
+      .get(`http://localhost:${getPort(io)}/socket.io/default/`)
+      .query({ transport: "polling", EIO: 4 })
+      .set("Origin", "http://localhost:54024")
+      .end((err, res) => {
+        expect(res.status).to.be(200);
+
+        expect(res.headers["access-control-allow-origin"]).to.be(
+          "http://localhost:54024"
+        );
+        expect(res.headers["access-control-allow-credentials"]).to.be("true");
+        success(done, io);
+      });
+  });
+
+  it("should allow request if custom function in opts.allowRequest returns true", (done) => {
+    const io = new Server(0, {
+      allowRequest: (req, callback) => callback(null, true),
+    });
+
+    request
+      .get(`http://localhost:${getPort(io)}/socket.io/default/`)
+      .query({ transport: "polling", EIO: 4 })
+      .end((err, res) => {
+        expect(res.status).to.be(200);
+        success(done, io);
+      });
+  });
+
+  it("should disallow request if custom function in opts.allowRequest returns false", (done) => {
+    const io = new Server(0, {
+      allowRequest: (req, callback) => callback(null, false),
+    });
+    request
+      .get(`http://localhost:${getPort(io)}/socket.io/default/`)
+      .set("origin", "http://foo.example")
+      .query({ transport: "polling", EIO: 4 })
+      .end((err, res) => {
+        expect(res.status).to.be(403);
+        success(done, io);
+      });
+  });
+});

test/index.ts

@@ -0,0 +1,23 @@
+"use strict";
+
+import expect from "expect.js";
+
+describe("socket.io", () => {
+  it("should be the same version as client", () => {
+    const version = require("../package").version;
+    expect(version).to.be(require("socket.io-client/package.json").version);
+  });
+
+  require("./server-attachment");
+  require("./handshake");
+  require("./close");
+  require("./namespaces");
+  require("./socket");
+  require("./messaging-many");
+  require("./middleware");
+  require("./socket-middleware");
+  require("./v2-compatibility");
+  require("./socket-timeout");
+  require("./uws");
+  require("./utility-methods");
+});

test/messaging-many.ts

@@ -0,0 +1,501 @@
+import { Server } from "..";
+import expect from "expect.js";
+import {
+  createClient,
+  createPartialDone,
+  success,
+  successFn,
+  waitFor,
+} from "./support/util";
+
+describe("messaging many", () => {
+  it("emits to a namespace", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/test");
+
+    const partialDone = createPartialDone(
+      2,
+      successFn(done, io, socket1, socket2, socket3)
+    );
+
+    socket1.on("a", (a) => {
+      expect(a).to.be("b");
+      partialDone();
+    });
+    socket2.on("a", (a) => {
+      expect(a).to.be("b");
+      partialDone();
+    });
+    socket3.on("a", () => {
+      done(new Error("not"));
+    });
+
+    let sockets = 3;
+    io.on("connection", () => {
+      --sockets || emit();
+    });
+    io.of("/test", () => {
+      --sockets || emit();
+    });
+
+    function emit() {
+      io.emit("a", "b");
+    }
+  });
+
+  it("emits binary data to a namespace", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/test");
+
+    const partialDone = createPartialDone(
+      2,
+      successFn(done, io, socket1, socket2, socket3)
+    );
+
+    socket1.on("bin", (a) => {
+      expect(Buffer.isBuffer(a)).to.be(true);
+      partialDone();
+    });
+    socket2.on("bin", (a) => {
+      expect(Buffer.isBuffer(a)).to.be(true);
+      partialDone();
+    });
+    socket3.on("bin", () => {
+      done(new Error("not"));
+    });
+
+    let sockets = 3;
+    io.on("connection", () => {
+      --sockets || emit();
+    });
+    io.of("/test", () => {
+      --sockets || emit();
+    });
+
+    function emit() {
+      io.emit("bin", Buffer.alloc(10));
+    }
+  });
+
+  it("emits to the rest", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/test");
+
+    socket1.on("a", (a) => {
+      expect(a).to.be("b");
+      socket1.emit("finish");
+    });
+    socket2.emit("broadcast");
+    socket2.on("a", () => {
+      done(new Error("done"));
+    });
+    socket3.on("a", () => {
+      done(new Error("not"));
+    });
+
+    io.on("connection", (socket) => {
+      socket.on("broadcast", () => {
+        socket.broadcast.emit("a", "b");
+      });
+      socket.on("finish", () => {
+        success(done, io, socket1, socket2, socket3);
+      });
+    });
+  });
+
+  it("emits to rooms", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+
+    socket2.on("a", () => {
+      done(new Error("not"));
+    });
+    socket1.on("a", () => {
+      success(done, io, socket1, socket2);
+    });
+    socket1.emit("join", "woot");
+    socket1.emit("emit", "woot");
+
+    io.on("connection", (socket) => {
+      socket.on("join", (room, fn) => {
+        socket.join(room);
+        fn && fn();
+      });
+
+      socket.on("emit", (room) => {
+        io.in(room).emit("a");
+      });
+    });
+  });
+
+  it("emits to rooms avoiding dupes", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+
+    const partialDone = createPartialDone(
+      2,
+      successFn(done, io, socket1, socket2)
+    );
+
+    socket2.on("a", () => {
+      done(new Error("not"));
+    });
+    socket1.on("a", partialDone);
+    socket2.on("b", partialDone);
+
+    socket1.emit("join", "woot");
+    socket1.emit("join", "test");
+    socket2.emit("join", "third", () => {
+      socket2.emit("emit");
+    });
+
+    io.on("connection", (socket) => {
+      socket.on("join", (room, fn) => {
+        socket.join(room);
+        fn && fn();
+      });
+
+      socket.on("emit", () => {
+        io.in("woot").in("test").emit("a");
+        io.in("third").emit("b");
+      });
+    });
+  });
+
+  it("broadcasts to rooms", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    const partialDone = createPartialDone(
+      2,
+      successFn(done, io, socket1, socket2, socket3)
+    );
+
+    socket1.emit("join", "woot");
+    socket2.emit("join", "test");
+    socket3.emit("join", "test", () => {
+      socket3.emit("broadcast");
+    });
+
+    socket1.on("a", () => {
+      done(new Error("not"));
+    });
+    socket2.on("a", () => {
+      partialDone();
+    });
+    socket3.on("a", () => {
+      done(new Error("not"));
+    });
+    socket3.on("b", () => {
+      partialDone();
+    });
+
+    io.on("connection", (socket) => {
+      socket.on("join", (room, fn) => {
+        socket.join(room);
+        fn && fn();
+      });
+
+      socket.on("broadcast", () => {
+        socket.broadcast.to("test").emit("a");
+        socket.emit("b");
+      });
+    });
+  });
+
+  it("broadcasts binary data to rooms", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    const partialDone = createPartialDone(
+      2,
+      successFn(done, io, socket1, socket2, socket3)
+    );
+
+    socket1.emit("join", "woot");
+    socket2.emit("join", "test");
+    socket3.emit("join", "test", () => {
+      socket3.emit("broadcast");
+    });
+
+    socket1.on("bin", (data) => {
+      throw new Error("got bin in socket1");
+    });
+    socket2.on("bin", (data) => {
+      expect(Buffer.isBuffer(data)).to.be(true);
+      partialDone();
+    });
+    socket2.on("bin2", (data) => {
+      throw new Error("socket2 got bin2");
+    });
+    socket3.on("bin", (data) => {
+      throw new Error("socket3 got bin");
+    });
+    socket3.on("bin2", (data) => {
+      expect(Buffer.isBuffer(data)).to.be(true);
+      partialDone();
+    });
+
+    io.on("connection", (socket) => {
+      socket.on("join", (room, fn) => {
+        socket.join(room);
+        fn && fn();
+      });
+      socket.on("broadcast", () => {
+        socket.broadcast.to("test").emit("bin", Buffer.alloc(5));
+        socket.emit("bin2", Buffer.alloc(5));
+      });
+    });
+  });
+
+  it("keeps track of rooms", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io);
+
+    io.on("connection", (s) => {
+      s.join("a");
+      expect(s.rooms).to.contain(s.id, "a");
+      s.join("b");
+      expect(s.rooms).to.contain(s.id, "a", "b");
+      s.join("c");
+      expect(s.rooms).to.contain(s.id, "a", "b", "c");
+      s.leave("b");
+      expect(s.rooms).to.contain(s.id, "a", "c");
+      (s as any).leaveAll();
+      expect(s.rooms.size).to.eql(0);
+
+      success(done, io, socket);
+    });
+  });
+
+  it("deletes empty rooms", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io);
+
+    io.on("connection", (s) => {
+      s.join("a");
+      expect(s.nsp.adapter.rooms).to.contain("a");
+      s.leave("a");
+      expect(s.nsp.adapter.rooms).to.not.contain("a");
+
+      success(done, io, socket);
+    });
+  });
+
+  it("should properly cleanup left rooms", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io);
+
+    io.on("connection", (s) => {
+      s.join("a");
+      expect(s.rooms).to.contain(s.id, "a");
+      s.join("b");
+      expect(s.rooms).to.contain(s.id, "a", "b");
+      s.leave("unknown");
+      expect(s.rooms).to.contain(s.id, "a", "b");
+      (s as any).leaveAll();
+      expect(s.rooms.size).to.eql(0);
+
+      success(done, io, socket);
+    });
+  });
+
+  it("allows to join several rooms at once", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io);
+
+    io.on("connection", (s) => {
+      s.join(["a", "b", "c"]);
+      expect(s.rooms).to.contain(s.id, "a", "b", "c");
+      success(done, io, socket);
+    });
+  });
+
+  it("should exclude specific sockets when broadcasting", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    socket2.on("a", () => {
+      done(new Error("not"));
+    });
+    socket3.on("a", () => {
+      done(new Error("not"));
+    });
+    socket1.on("a", successFn(done, io, socket1, socket2, socket3));
+
+    io.on("connection", (socket) => {
+      socket.on("exclude", (id) => {
+        socket.broadcast.except(id).emit("a");
+      });
+    });
+
+    socket2.on("connect", () => {
+      socket3.emit("exclude", socket2.id);
+    });
+  });
+
+  it("should exclude a specific room when broadcasting", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    socket2.on("a", () => {
+      done(new Error("not"));
+    });
+    socket3.on("a", () => {
+      done(new Error("not"));
+    });
+    socket1.on("a", successFn(done, io, socket1, socket2, socket3));
+
+    io.on("connection", (socket) => {
+      socket.on("join", (room, cb) => {
+        socket.join(room);
+        cb();
+      });
+      socket.on("broadcast", () => {
+        socket.broadcast.except("room1").emit("a");
+      });
+    });
+
+    socket2.emit("join", "room1", () => {
+      socket3.emit("broadcast");
+    });
+  });
+
+  it("should return an immutable broadcast operator", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io);
+
+    io.on("connection", (socket) => {
+      const operator = socket.local
+        .compress(false)
+        .to(["room1", "room2"])
+        .except("room3");
+      operator.compress(true).emit("hello");
+      operator.volatile.emit("hello");
+      operator.to("room4").emit("hello");
+      operator.except("room5").emit("hello");
+      socket.emit("hello");
+      socket.to("room6").emit("hello");
+      // @ts-ignore
+      expect(operator.rooms).to.contain("room1", "room2");
+      // @ts-ignore
+      expect(operator.rooms).to.not.contain("room4", "room5", "room6");
+      // @ts-ignore
+      expect(operator.exceptRooms).to.contain("room3");
+      // @ts-ignore
+      expect(operator.flags).to.eql({ local: true, compress: false });
+
+      success(done, io, clientSocket);
+    });
+  });
+
+  it("should broadcast and expect multiple acknowledgements", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    socket1.on("some event", (cb) => {
+      cb(1);
+    });
+
+    socket2.on("some event", (cb) => {
+      cb(2);
+    });
+
+    socket3.on("some event", (cb) => {
+      cb(3);
+    });
+
+    Promise.all([
+      waitFor(socket1, "connect"),
+      waitFor(socket2, "connect"),
+      waitFor(socket3, "connect"),
+    ]).then(() => {
+      io.timeout(2000).emit("some event", (err, responses) => {
+        expect(err).to.be(null);
+        expect(responses).to.have.length(3);
+        expect(responses).to.contain(1, 2, 3);
+
+        success(done, io, socket1, socket2, socket3);
+      });
+    });
+  });
+
+  it("should fail when a client does not acknowledge the event in the given delay", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    socket1.on("some event", (cb) => {
+      cb(1);
+    });
+
+    socket2.on("some event", (cb) => {
+      cb(2);
+    });
+
+    socket3.on("some event", () => {
+      // timeout
+    });
+
+    Promise.all([
+      waitFor(socket1, "connect"),
+      waitFor(socket2, "connect"),
+      waitFor(socket3, "connect"),
+    ]).then(() => {
+      io.timeout(200).emit("some event", (err, responses) => {
+        expect(err).to.be.an(Error);
+        expect(responses).to.have.length(2);
+        expect(responses).to.contain(1, 2);
+
+        success(done, io, socket1, socket2, socket3);
+      });
+    });
+  });
+
+  it("should broadcast and return if the packet is sent to 0 client", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/", { multiplex: false });
+    const socket2 = createClient(io, "/", { multiplex: false });
+    const socket3 = createClient(io, "/", { multiplex: false });
+
+    socket1.on("some event", () => {
+      done(new Error("should not happen"));
+    });
+
+    socket2.on("some event", () => {
+      done(new Error("should not happen"));
+    });
+
+    socket3.on("some event", () => {
+      done(new Error("should not happen"));
+    });
+
+    io.to("room123")
+      .timeout(200)
+      .emit("some event", (err, responses) => {
+        expect(err).to.be(null);
+        expect(responses).to.have.length(0);
+
+        success(done, io, socket1, socket2, socket3);
+      });
+  });
+});

test/middleware.ts

@@ -0,0 +1,210 @@
+import { Server, Socket } from "..";
+import expect from "expect.js";
+import {
+  success,
+  createClient,
+  successFn,
+  createPartialDone,
+} from "./support/util";
+
+describe("middleware", () => {
+  it("should call functions", (done) => {
+    const io = new Server(0);
+
+    let run = 0;
+    io.use((socket, next) => {
+      expect(socket).to.be.a(Socket);
+      run++;
+      next();
+    });
+    io.use((socket, next) => {
+      expect(socket).to.be.a(Socket);
+      run++;
+      next();
+    });
+
+    const socket = createClient(io);
+    socket.on("connect", () => {
+      expect(run).to.be(2);
+
+      success(done, io, socket);
+    });
+  });
+
+  it("should pass errors", (done) => {
+    const io = new Server(0);
+
+    io.use((socket, next) => {
+      next(new Error("Authentication error"));
+    });
+    io.use((socket, next) => {
+      done(new Error("nope"));
+    });
+
+    const socket = createClient(io);
+    socket.on("connect", () => {
+      done(new Error("nope"));
+    });
+    socket.on("connect_error", (err) => {
+      expect(err.message).to.be("Authentication error");
+
+      success(done, io, socket);
+    });
+  });
+
+  it("should pass an object", (done) => {
+    const io = new Server(0);
+
+    io.use((socket, next) => {
+      const err = new Error("Authentication error");
+      // @ts-ignore
+      err.data = { a: "b", c: 3 };
+      next(err);
+    });
+
+    const socket = createClient(io);
+    socket.on("connect", () => {
+      done(new Error("nope"));
+    });
+    socket.on("connect_error", (err) => {
+      expect(err).to.be.an(Error);
+      expect(err.message).to.eql("Authentication error");
+      // @ts-ignore
+      expect(err.data).to.eql({ a: "b", c: 3 });
+
+      success(done, io, socket);
+    });
+  });
+
+  it("should only call connection after fns", (done) => {
+    const io = new Server(0);
+
+    io.use((socket: any, next) => {
+      socket.name = "guillermo";
+      next();
+    });
+
+    const clientSocket = createClient(io);
+    io.on("connection", (socket) => {
+      expect((socket as any).name).to.be("guillermo");
+
+      success(done, io, clientSocket);
+    });
+  });
+
+  it("should only call connection after (lengthy) fns", (done) => {
+    const io = new Server(0);
+
+    let authenticated = false;
+
+    io.use((socket, next) => {
+      setTimeout(() => {
+        authenticated = true;
+        next();
+      }, 300);
+    });
+
+    const socket = createClient(io);
+    socket.on("connect", () => {
+      expect(authenticated).to.be(true);
+
+      success(done, io, socket);
+    });
+  });
+
+  it("should be ignored if socket gets closed", (done) => {
+    const io = new Server(0);
+
+    let socket;
+    io.use((s, next) => {
+      socket.io.engine.close();
+      s.client.conn.on("close", () => {
+        process.nextTick(next);
+        setTimeout(() => {
+          success(done, io, socket);
+        }, 50);
+      });
+    });
+
+    socket = createClient(io);
+    io.on("connection", (socket) => {
+      done(new Error("should not fire"));
+    });
+  });
+
+  it("should call functions in expected order", (done) => {
+    const io = new Server(0);
+
+    const result: number[] = [];
+
+    io.use(() => {
+      done(new Error("should not fire"));
+    });
+    io.of("/chat").use((socket, next) => {
+      result.push(1);
+      setTimeout(next, 50);
+    });
+    io.of("/chat").use((socket, next) => {
+      result.push(2);
+      setTimeout(next, 50);
+    });
+    io.of("/chat").use((socket, next) => {
+      result.push(3);
+      setTimeout(next, 50);
+    });
+
+    const chat = createClient(io, "/chat");
+    chat.on("connect", () => {
+      expect(result).to.eql([1, 2, 3]);
+
+      success(done, io, chat);
+    });
+  });
+
+  it("should disable the merge of handshake packets", (done) => {
+    const io = new Server(0);
+
+    io.use((socket, next) => {
+      next();
+    });
+
+    const socket = createClient(io);
+    socket.on("connect", successFn(done, io, socket));
+  });
+
+  it("should work with a custom namespace", (done) => {
+    const io = new Server(0);
+    const socket1 = createClient(io, "/");
+    const socket2 = createClient(io, "/chat");
+
+    const partialDone = createPartialDone(
+      2,
+      successFn(done, io, socket1, socket2)
+    );
+
+    io.of("/chat").use((socket, next) => {
+      next();
+    });
+
+    socket1.on("connect", partialDone);
+    socket2.on("connect", partialDone);
+  });
+
+  it("should only set `connected` to true after the middleware execution", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io, "/");
+
+    io.use((socket, next) => {
+      expect(socket.connected).to.be(false);
+      expect(socket.disconnected).to.be(true);
+      next();
+    });
+
+    io.on("connection", (socket) => {
+      expect(socket.connected).to.be(true);
+      expect(socket.disconnected).to.be(false);
+
+      success(done, io, clientSocket);
+    });
+  });
+});

test/namespaces.ts

@@ -0,0 +1,575 @@
+import type { SocketId } from "socket.io-adapter";
+import { Server, Namespace, Socket } from "..";
+import expect from "expect.js";
+import {
+  success,
+  createClient,
+  successFn,
+  createPartialDone,
+} from "./support/util";
+
+describe("namespaces", () => {
+  it("should be accessible through .sockets", () => {
+    const io = new Server();
+    expect(io.sockets).to.be.a(Namespace);
+  });
+
+  it("should be aliased", () => {
+    const io = new Server();
+    expect(io.use).to.be.a("function");
+    expect(io.to).to.be.a("function");
+    expect(io["in"]).to.be.a("function");
+    expect(io.emit).to.be.a("function");
+    expect(io.send).to.be.a("function");
+    expect(io.write).to.be.a("function");
+    expect(io.allSockets).to.be.a("function");
+    expect(io.compress).to.be.a("function");
+  });
+
+  it("should return an immutable broadcast operator", () => {
+    const io = new Server();
+    const operator = io.local.to(["room1", "room2"]).except("room3");
+    operator.compress(true).emit("hello");
+    operator.volatile.emit("hello");
+    operator.to("room4").emit("hello");
+    operator.except("room5").emit("hello");
+    io.to("room6").emit("hello");
+    // @ts-ignore
+    expect(operator.rooms).to.contain("room1", "room2");
+    // @ts-ignore
+    expect(operator.exceptRooms).to.contain("room3");
+    // @ts-ignore
+    expect(operator.flags).to.eql({ local: true });
+  });
+
+  it("should automatically connect", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io);
+    socket.on("connect", successFn(done, io, socket));
+  });
+
+  it("should fire a `connection` event", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io);
+
+    io.on("connection", (socket) => {
+      expect(socket).to.be.a(Socket);
+      success(done, io, clientSocket);
+    });
+  });
+
+  it("should fire a `connect` event", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io);
+
+    io.on("connect", (socket) => {
+      expect(socket).to.be.a(Socket);
+      success(done, io, clientSocket);
+    });
+  });
+
+  it("should work with many sockets", (done) => {
+    const io = new Server(0);
+    io.of("/chat");
+    io.of("/news");
+    const chat = createClient(io, "/chat");
+    const news = createClient(io, "/news");
+
+    let total = 2;
+    chat.on("connect", () => {
+      --total || success(done, io, chat, news);
+    });
+    news.on("connect", () => {
+      --total || success(done, io, chat, news);
+    });
+  });
+
+  it('should be able to equivalently start with "" or "/" on server', (done) => {
+    const io = new Server(0);
+    const c1 = createClient(io, "/");
+    const c2 = createClient(io, "/abc");
+
+    let total = 2;
+    io.of("").on("connection", () => {
+      --total || success(done, io, c1, c2);
+    });
+    io.of("abc").on("connection", () => {
+      --total || success(done, io, c1, c2);
+    });
+  });
+
+  it('should be equivalent for "" and "/" on client', (done) => {
+    const io = new Server(0);
+    const c1 = createClient(io, "");
+
+    io.of("/").on("connection", successFn(done, io, c1));
+  });
+
+  it("should work with `of` and many sockets", (done) => {
+    const io = new Server(0);
+    const chat = createClient(io, "/chat");
+    const news = createClient(io, "/news");
+
+    let total = 2;
+    io.of("/news").on("connection", (socket) => {
+      expect(socket).to.be.a(Socket);
+      --total || success(done, io, chat, news);
+    });
+    io.of("/news").on("connection", (socket) => {
+      expect(socket).to.be.a(Socket);
+      --total || success(done, io, chat, news);
+    });
+  });
+
+  it("should work with `of` second param", (done) => {
+    const io = new Server(0);
+    const chat = createClient(io, "/chat");
+    const news = createClient(io, "/news");
+
+    let total = 2;
+    io.of("/news", (socket) => {
+      expect(socket).to.be.a(Socket);
+      --total || success(done, io, chat, news);
+    });
+    io.of("/news", (socket) => {
+      expect(socket).to.be.a(Socket);
+      --total || success(done, io, chat, news);
+    });
+  });
+
+  it("should disconnect upon transport disconnection", (done) => {
+    const io = new Server(0);
+    const chat = createClient(io, "/chat");
+    const news = createClient(io, "/news");
+
+    let total = 2;
+    let totald = 2;
+    let s;
+    io.of("/news", (socket) => {
+      socket.on("disconnect", (reason) => {
+        --totald || success(done, io, chat, news);
+      });
+      --total || close();
+    });
+    io.of("/chat", (socket) => {
+      s = socket;
+      socket.on("disconnect", (reason) => {
+        --totald || success(done, io, chat, news);
+      });
+      --total || close();
+    });
+    function close() {
+      s.disconnect(true);
+    }
+  });
+
+  it("should fire a `disconnecting` event just before leaving all rooms", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io);
+
+    io.on("connection", (s) => {
+      s.join("a");
+      // FIXME not sure why process.nextTick() is needed here
+      process.nextTick(() => s.disconnect());
+
+      let total = 2;
+      s.on("disconnecting", (reason) => {
+        expect(s.rooms).to.contain(s.id, "a");
+        total--;
+      });
+
+      s.on("disconnect", (reason) => {
+        expect(s.rooms.size).to.eql(0);
+        --total || success(done, io, socket);
+      });
+    });
+  });
+
+  it("should return error connecting to non-existent namespace", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io, "/doesnotexist");
+
+    socket.on("connect_error", (err) => {
+      expect(err.message).to.be("Invalid namespace");
+      success(done, io);
+    });
+  });
+
+  it("should not reuse same-namespace connections", (done) => {
+    const io = new Server(0);
+    const clientSocket1 = createClient(io);
+    const clientSocket2 = createClient(io);
+
+    let connections = 0;
+    io.on("connection", () => {
+      connections++;
+      if (connections === 2) {
+        success(done, io, clientSocket1, clientSocket2);
+      }
+    });
+  });
+
+  it("should find all clients in a namespace", (done) => {
+    const io = new Server(0);
+    const chatSids: string[] = [];
+    let otherSid: SocketId | null = null;
+
+    const c1 = createClient(io, "/chat");
+    const c2 = createClient(io, "/chat", { forceNew: true });
+    const c3 = createClient(io, "/other", { forceNew: true });
+
+    let total = 3;
+    io.of("/chat").on("connection", (socket) => {
+      chatSids.push(socket.id);
+      --total || getSockets();
+    });
+    io.of("/other").on("connection", (socket) => {
+      otherSid = socket.id;
+      --total || getSockets();
+    });
+
+    async function getSockets() {
+      const sids = await io.of("/chat").allSockets();
+
+      expect(sids).to.contain(chatSids[0], chatSids[1]);
+      expect(sids).to.not.contain(otherSid);
+      success(done, io, c1, c2, c3);
+    }
+  });
+
+  it("should find all clients in a namespace room", (done) => {
+    const io = new Server(0);
+    let chatFooSid: SocketId | null = null;
+    let chatBarSid: SocketId | null = null;
+    let otherSid: SocketId | null = null;
+
+    const c1 = createClient(io, "/chat");
+    const c2 = createClient(io, "/chat", { forceNew: true });
+    const c3 = createClient(io, "/other", { forceNew: true });
+
+    let chatIndex = 0;
+    let total = 3;
+    io.of("/chat").on("connection", (socket) => {
+      if (chatIndex++) {
+        socket.join("foo");
+        chatFooSid = socket.id;
+        --total || getSockets();
+      } else {
+        socket.join("bar");
+        chatBarSid = socket.id;
+        --total || getSockets();
+      }
+    });
+    io.of("/other").on("connection", (socket) => {
+      socket.join("foo");
+      otherSid = socket.id;
+      --total || getSockets();
+    });
+
+    async function getSockets() {
+      const sids = await io.of("/chat").in("foo").allSockets();
+
+      expect(sids).to.contain(chatFooSid);
+      expect(sids).to.not.contain(chatBarSid);
+      expect(sids).to.not.contain(otherSid);
+      success(done, io, c1, c2, c3);
+    }
+  });
+
+  it("should find all clients across namespace rooms", (done) => {
+    const io = new Server(0);
+    let chatFooSid: SocketId | null = null;
+    let chatBarSid: SocketId | null = null;
+    let otherSid: SocketId | null = null;
+
+    const c1 = createClient(io, "/chat");
+    const c2 = createClient(io, "/chat", { forceNew: true });
+    const c3 = createClient(io, "/other", { forceNew: true });
+
+    let chatIndex = 0;
+    let total = 3;
+    io.of("/chat").on("connection", (socket) => {
+      if (chatIndex++) {
+        socket.join("foo");
+        chatFooSid = socket.id;
+        --total || getSockets();
+      } else {
+        socket.join("bar");
+        chatBarSid = socket.id;
+        --total || getSockets();
+      }
+    });
+    io.of("/other").on("connection", (socket) => {
+      socket.join("foo");
+      otherSid = socket.id;
+      --total || getSockets();
+    });
+
+    async function getSockets() {
+      const sids = await io.of("/chat").allSockets();
+      expect(sids).to.contain(chatFooSid, chatBarSid);
+      expect(sids).to.not.contain(otherSid);
+      success(done, io, c1, c2, c3);
+    }
+  });
+
+  it("should not emit volatile event after regular event", (done) => {
+    const io = new Server(0);
+
+    let counter = 0;
+    io.of("/chat").on("connection", (s) => {
+      // Wait to make sure there are no packets being sent for opening the connection
+      setTimeout(() => {
+        io.of("/chat").emit("ev", "data");
+        io.of("/chat").volatile.emit("ev", "data");
+      }, 50);
+    });
+
+    const socket = createClient(io, "/chat");
+    socket.on("ev", () => {
+      counter++;
+    });
+
+    setTimeout(() => {
+      expect(counter).to.be(1);
+      success(done, io, socket);
+    }, 500);
+  });
+
+  it("should emit volatile event", (done) => {
+    const io = new Server(0);
+
+    let counter = 0;
+    io.of("/chat").on("connection", (s) => {
+      // Wait to make sure there are no packets being sent for opening the connection
+      setTimeout(() => {
+        io.of("/chat").volatile.emit("ev", "data");
+      }, 100);
+    });
+
+    const socket = createClient(io, "/chat");
+    socket.on("ev", () => {
+      counter++;
+    });
+
+    setTimeout(() => {
+      expect(counter).to.be(1);
+      success(done, io, socket);
+    }, 500);
+  });
+
+  it("should enable compression by default", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io, "/chat");
+
+    io.of("/chat").on("connection", (s) => {
+      s.conn.once("packetCreate", (packet) => {
+        expect(packet.options.compress).to.be(true);
+        success(done, io, socket);
+      });
+      io.of("/chat").emit("woot", "hi");
+    });
+  });
+
+  it("should disable compression", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io, "/chat");
+
+    io.of("/chat").on("connection", (s) => {
+      s.conn.once("packetCreate", (packet) => {
+        expect(packet.options.compress).to.be(false);
+        success(done, io, socket);
+      });
+      io.of("/chat").compress(false).emit("woot", "hi");
+    });
+  });
+
+  it("should throw on reserved event", () => {
+    const io = new Server();
+
+    expect(() => io.emit("connect")).to.throwException(
+      /"connect" is a reserved event name/
+    );
+  });
+
+  it("should close a client without namespace", (done) => {
+    const io = new Server(0, {
+      connectTimeout: 10,
+    });
+
+    const socket = createClient(io);
+
+    // @ts-ignore
+    socket.io.engine.write = () => {}; // prevent the client from sending a CONNECT packet
+
+    socket.on("disconnect", successFn(done, io, socket));
+  });
+
+  it("should exclude a specific socket when emitting", (done) => {
+    const io = new Server(0);
+
+    const socket1 = createClient(io, "/");
+    const socket2 = createClient(io, "/");
+
+    socket2.on("a", () => {
+      done(new Error("should not happen"));
+    });
+    socket1.on("a", successFn(done, io, socket1, socket2));
+
+    socket2.on("connect", () => {
+      io.except(socket2.id).emit("a");
+    });
+  });
+
+  it("should exclude a specific socket when emitting (in a namespace)", (done) => {
+    const io = new Server(0);
+
+    const nsp = io.of("/nsp");
+
+    const socket1 = createClient(io, "/nsp");
+    const socket2 = createClient(io, "/nsp");
+
+    socket2.on("a", () => {
+      done(new Error("not"));
+    });
+    socket1.on("a", successFn(done, io, socket1, socket2));
+
+    socket2.on("connect", () => {
+      nsp.except(socket2.id).emit("a");
+    });
+  });
+
+  it("should exclude a specific room when emitting", (done) => {
+    const io = new Server(0);
+
+    const nsp = io.of("/nsp");
+
+    const socket1 = createClient(io, "/nsp");
+    const socket2 = createClient(io, "/nsp");
+
+    socket1.on("a", successFn(done, io, socket1, socket2));
+    socket2.on("a", () => {
+      done(new Error("not"));
+    });
+
+    nsp.on("connection", (socket) => {
+      socket.on("broadcast", () => {
+        socket.join("room1");
+        nsp.except("room1").emit("a");
+      });
+    });
+
+    socket2.emit("broadcast");
+  });
+
+  it("should emit an 'new_namespace' event", (done) => {
+    const io = new Server();
+
+    io.on("new_namespace", (namespace) => {
+      expect(namespace.name).to.eql("/nsp");
+      done();
+    });
+
+    io.of("/nsp");
+  });
+
+  describe("dynamic namespaces", () => {
+    it("should allow connections to dynamic namespaces with a regex", (done) => {
+      const io = new Server(0);
+      const socket = createClient(io, "/dynamic-101");
+      const partialDone = createPartialDone(4, successFn(done, io, socket));
+
+      let dynamicNsp = io
+        .of(/^\/dynamic-\d+$/)
+        .on("connect", (socket) => {
+          expect(socket.nsp.name).to.be("/dynamic-101");
+          dynamicNsp.emit("hello", 1, "2", { 3: "4" });
+          partialDone();
+        })
+        .use((socket, next) => {
+          next();
+          partialDone();
+        });
+      socket.on("connect_error", (err) => {
+        expect().fail();
+      });
+      socket.on("connect", () => {
+        partialDone();
+      });
+      socket.on("hello", (a, b, c) => {
+        expect(a).to.eql(1);
+        expect(b).to.eql("2");
+        expect(c).to.eql({ 3: "4" });
+        partialDone();
+      });
+    });
+
+    it("should allow connections to dynamic namespaces with a function", (done) => {
+      const io = new Server(0);
+      const socket = createClient(io, "/dynamic-101");
+
+      io.of((name, query, next) => next(null, "/dynamic-101" === name));
+      socket.on("connect", successFn(done, io, socket));
+    });
+
+    it("should disallow connections when no dynamic namespace matches", (done) => {
+      const io = new Server(0);
+      const socket = createClient(io, "/abc");
+      io.of(/^\/dynamic-\d+$/);
+      io.of((name, query, next) => next(null, "/dynamic-101" === name));
+
+      socket.on("connect_error", (err) => {
+        expect(err.message).to.be("Invalid namespace");
+        success(done, io, socket);
+      });
+    });
+
+    it("should emit an 'new_namespace' event for a dynamic namespace", (done) => {
+      const io = new Server(0);
+      io.of(/^\/dynamic-\d+$/);
+      const socket = createClient(io, "/dynamic-101");
+
+      io.on("new_namespace", (namespace) => {
+        expect(namespace.name).to.be("/dynamic-101");
+
+        success(done, io, socket);
+      });
+    });
+
+    it("should handle race conditions with dynamic namespaces (#4136)", (done) => {
+      const io = new Server(0);
+      const counters = {
+        connected: 0,
+        created: 0,
+        events: 0,
+      };
+      const buffer: Function[] = [];
+      io.on("new_namespace", (namespace) => {
+        counters.created++;
+      });
+
+      const handler = () => {
+        if (++counters.events === 2) {
+          expect(counters.created).to.equal(1);
+          success(done, io, one, two);
+        }
+      };
+
+      io.of((name, query, next) => {
+        buffer.push(next);
+        if (buffer.length === 2) {
+          buffer.forEach((next) => next(null, true));
+        }
+      }).on("connection", (socket) => {
+        if (++counters.connected === 2) {
+          io.of("/dynamic-101").emit("message");
+        }
+      });
+
+      let one = createClient(io, "/dynamic-101");
+      let two = createClient(io, "/dynamic-101");
+      one.on("message", handler);
+      two.on("message", handler);
+    });
+  });
+});

test/server-attachment.ts

@@ -0,0 +1,170 @@
+import { Server } from "..";
+import { createServer } from "http";
+import request from "supertest";
+import expect from "expect.js";
+import { getPort, successFn } from "./support/util";
+
+describe("server attachment", () => {
+  describe("http.Server", () => {
+    const clientVersion = require("socket.io-client/package.json").version;
+
+    const testSource = (filename) => (done) => {
+      const srv = createServer();
+      new Server(srv);
+      request(srv)
+        .get("/socket.io/" + filename)
+        .buffer(true)
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.headers["content-type"]).to.be("application/javascript");
+          expect(res.headers.etag).to.be('"' + clientVersion + '"');
+          expect(res.headers["x-sourcemap"]).to.be(undefined);
+          expect(res.text).to.match(/engine\.io/);
+          expect(res.status).to.be(200);
+          done();
+        });
+    };
+
+    const testSourceMap = (filename) => (done) => {
+      const srv = createServer();
+      new Server(srv);
+      request(srv)
+        .get("/socket.io/" + filename)
+        .buffer(true)
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.headers["content-type"]).to.be("application/json");
+          expect(res.headers.etag).to.be('"' + clientVersion + '"');
+          expect(res.text).to.match(/engine\.io/);
+          expect(res.status).to.be(200);
+          done();
+        });
+    };
+
+    it("should serve client", testSource("socket.io.js"));
+    it(
+      "should serve client with query string",
+      testSource("socket.io.js?buster=" + Date.now())
+    );
+    it("should serve source map", testSourceMap("socket.io.js.map"));
+    it("should serve client (min)", testSource("socket.io.min.js"));
+
+    it("should serve source map (min)", testSourceMap("socket.io.min.js.map"));
+
+    it("should serve client (gzip)", (done) => {
+      const srv = createServer();
+      new Server(srv);
+      request(srv)
+        .get("/socket.io/socket.io.js")
+        .set("accept-encoding", "gzip,br,deflate")
+        .buffer(true)
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.headers["content-encoding"]).to.be("gzip");
+          expect(res.status).to.be(200);
+          done();
+        });
+    });
+
+    it(
+      "should serve bundle with msgpack parser",
+      testSource("socket.io.msgpack.min.js")
+    );
+
+    it(
+      "should serve source map for bundle with msgpack parser",
+      testSourceMap("socket.io.msgpack.min.js.map")
+    );
+
+    it("should serve the ESM bundle", testSource("socket.io.esm.min.js"));
+
+    it(
+      "should serve the source map for the ESM bundle",
+      testSourceMap("socket.io.esm.min.js.map")
+    );
+
+    it("should handle 304", (done) => {
+      const srv = createServer();
+      new Server(srv);
+      request(srv)
+        .get("/socket.io/socket.io.js")
+        .set("If-None-Match", '"' + clientVersion + '"')
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.statusCode).to.be(304);
+          done();
+        });
+    });
+
+    it("should handle 304", (done) => {
+      const srv = createServer();
+      new Server(srv);
+      request(srv)
+        .get("/socket.io/socket.io.js")
+        .set("If-None-Match", 'W/"' + clientVersion + '"')
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.statusCode).to.be(304);
+          done();
+        });
+    });
+
+    it("should not serve static files", (done) => {
+      const srv = createServer();
+      new Server(srv, { serveClient: false });
+      request(srv).get("/socket.io/socket.io.js").expect(400, done);
+    });
+
+    it("should work with #attach", (done) => {
+      const srv = createServer((req, res) => {
+        res.writeHead(404);
+        res.end();
+      });
+      const sockets = new Server();
+      sockets.attach(srv);
+      request(srv)
+        .get("/socket.io/socket.io.js")
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.status).to.be(200);
+          done();
+        });
+    });
+
+    it("should work with #attach (and merge options)", () => {
+      const srv = createServer((req, res) => {
+        res.writeHead(404);
+        res.end();
+      });
+      const server = new Server({
+        pingTimeout: 6000,
+      });
+      server.attach(srv, {
+        pingInterval: 24000,
+      });
+      // @ts-ignore
+      expect(server.eio.opts.pingTimeout).to.eql(6000);
+      // @ts-ignore
+      expect(server.eio.opts.pingInterval).to.eql(24000);
+      server.close();
+    });
+  });
+
+  describe("port", () => {
+    it("should be bound", (done) => {
+      const io = new Server(0);
+
+      request(`http://localhost:${getPort(io)}`)
+        .get("/socket.io/socket.io.js")
+        .expect(200, successFn(done, io));
+    });
+
+    it("with listen", (done) => {
+      const io = new Server().listen(0);
+
+      request(`http://localhost:${getPort(io)}`)
+        .get("/socket.io/socket.io.js")
+        .expect(200, successFn(done, io));
+    });
+  });
+});

test/socket-middleware.ts

@@ -0,0 +1,60 @@
+import { Server } from "..";
+import expect from "expect.js";
+import { success, createClient } from "./support/util";
+
+describe("socket middleware", () => {
+  it("should call functions", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io, "/", { multiplex: false });
+
+    clientSocket.emit("join", "woot");
+
+    let run = 0;
+
+    io.on("connection", (socket) => {
+      socket.use((event, next) => {
+        expect(event).to.eql(["join", "woot"]);
+        event.unshift("wrap");
+        run++;
+        next();
+      });
+      socket.use((event, next) => {
+        expect(event).to.eql(["wrap", "join", "woot"]);
+        run++;
+        next();
+      });
+      socket.on("wrap", (data1, data2) => {
+        expect(data1).to.be("join");
+        expect(data2).to.be("woot");
+        expect(run).to.be(2);
+
+        success(done, io, clientSocket);
+      });
+    });
+  });
+
+  it("should pass errors", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io, "/", { multiplex: false });
+
+    clientSocket.emit("join", "woot");
+
+    io.on("connection", (socket) => {
+      socket.use((event, next) => {
+        next(new Error("Authentication error"));
+      });
+      socket.use((event, next) => {
+        done(new Error("should not happen"));
+      });
+      socket.on("join", () => {
+        done(new Error("should not happen"));
+      });
+      socket.on("error", (err) => {
+        expect(err).to.be.an(Error);
+        expect(err.message).to.eql("Authentication error");
+
+        success(done, io, clientSocket);
+      });
+    });
+  });
+});

test/socket.io.test-d.ts

@@ -4,6 +4,7 @@ import type { DefaultEventsMap } from "../lib/typed-events";
 import { createServer } from "http";
 import { expectError, expectType } from "tsd";
 import { Adapter } from "socket.io-adapter";
+import type { DisconnectReason } from "../lib/socket";
 
 // This file is run by tsd, not mocha.
 
@@ -17,10 +18,10 @@ describe("server", () => {
           sio.on("connection", (s) => {
             expectType<Socket<DefaultEventsMap, DefaultEventsMap>>(s);
             s.on("disconnect", (reason) => {
-              expectType<string>(reason);
+              expectType<DisconnectReason>(reason);
             });
             s.on("disconnecting", (reason) => {
-              expectType<string>(reason);
+              expectType<DisconnectReason>(reason);
             });
           });
           sio.on("connect", (s) => {
@@ -208,6 +209,10 @@ describe("server", () => {
         const srv = createServer();
         const sio = new Server<ClientToServerEvents, ServerToClientEvents>(srv);
         srv.listen(() => {
+          sio.emit("helloFromServer", "hi", 1);
+          sio.to("room").emit("helloFromServer", "hi", 1);
+          sio.timeout(1000).emit("helloFromServer", "hi", 1);
+
           sio.on("connection", (s) => {
             s.emit("helloFromServer", "hi", 10);
             done();
@@ -219,6 +224,10 @@ describe("server", () => {
         const srv = createServer();
         const sio = new Server<ClientToServerEvents, ServerToClientEvents>(srv);
         srv.listen(() => {
+          expectError(sio.emit("helloFromClient"));
+          expectError(sio.to("room").emit("helloFromClient"));
+          expectError(sio.timeout(1000).to("room").emit("helloFromClient"));
+
           sio.on("connection", (s) => {
             expectError(s.emit("helloFromClient", "hi"));
             expectError(s.emit("helloFromServer", "hi", 10, "10"));
@@ -233,7 +242,7 @@ describe("server", () => {
     });
   });
 
-  describe("listen and emit event maps", () => {
+  describe("listen and emit event maps for the serverSideEmit method", () => {
     interface ClientToServerEvents {
       helloFromClient: (message: string) => void;
     }

test/support/util.ts

@@ -31,16 +31,50 @@ expect.Assertion.prototype.contain = function (...args) {
 
 export function createClient(
   io: Server,
-  nsp: string,
-  opts?: ManagerOptions & SocketOptions
+  nsp: string = "/",
+  opts?: Partial<ManagerOptions & SocketOptions>
 ): ClientSocket {
   // @ts-ignore
   const port = io.httpServer.address().port;
   return ioc(`http://localhost:${port}${nsp}`, opts);
 }
 
-export function success(done: Function, io: Server, client: ClientSocket) {
+export function success(
+  done: Function,
+  io: Server,
+  ...clients: ClientSocket[]
+) {
   io.close();
-  client.disconnect();
+  clients.forEach((client) => client.disconnect());
   done();
 }
+
+export function successFn(
+  done: () => void,
+  sio: Server,
+  ...clientSockets: ClientSocket[]
+) {
+  return () => success(done, sio, ...clientSockets);
+}
+
+export function getPort(io: Server): number {
+  // @ts-ignore
+  return io.httpServer.address().port;
+}
+
+export function createPartialDone(count: number, done: (err?: Error) => void) {
+  let i = 0;
+  return () => {
+    if (++i === count) {
+      done();
+    } else if (i > count) {
+      done(new Error(`partialDone() called too many times: ${i} > ${count}`));
+    }
+  };
+}
+
+export function waitFor(emitter, event) {
+  return new Promise((resolve) => {
+    emitter.once(event, resolve);
+  });
+}

test/utility-methods.ts

@@ -6,26 +6,10 @@ import expect from "expect.js";
 import type { AddressInfo } from "net";
 
 import "./support/util";
+import { createPartialDone } from "./support/util";
 
 const SOCKETS_COUNT = 3;
 
-const createPartialDone = (
-  count: number,
-  done: () => void,
-  callback?: () => void
-) => {
-  let i = 0;
-  return () => {
-    i++;
-    if (i === count) {
-      done();
-      if (callback) {
-        callback();
-      }
-    }
-  };
-};
-
 class DummyAdapter extends Adapter {
   fetchSockets(opts: BroadcastOptions): Promise<any[]> {
     return Promise.resolve([
@@ -49,7 +33,7 @@ class DummyAdapter extends Adapter {
   }
 }
 
-describe("socket.io", () => {
+describe("utility methods", () => {
   let io: Server, clientSockets: ClientSocket[], serverSockets: Socket[];
   beforeEach((done) => {
     const srv = createServer();
@@ -59,7 +43,12 @@ describe("socket.io", () => {
 
       clientSockets = [];
       for (let i = 0; i < SOCKETS_COUNT; i++) {
-        clientSockets.push(ioc(`http://localhost:${port}`));
+        clientSockets.push(
+          ioc(`http://localhost:${port}`, {
+            // FIXME needed so that clients are properly closed
+            transports: ["websocket"],
+          })
+        );
       }
 
       serverSockets = [];
@@ -77,100 +66,99 @@ describe("socket.io", () => {
     clientSockets.forEach((socket) => socket.disconnect());
   });
 
-  describe("utility methods", () => {
-    describe("fetchSockets", () => {
-      it("returns all socket instances", async () => {
-        const sockets = await io.fetchSockets();
-        expect(sockets.length).to.eql(3);
-      });
+  describe("fetchSockets", () => {
+    it("returns all socket instances", async () => {
+      const sockets = await io.fetchSockets();
+      expect(sockets.length).to.eql(3);
+    });
 
-      it("returns all socket instances in the given room", async () => {
-        serverSockets[0].join(["room1", "room2"]);
-        serverSockets[1].join("room1");
-        serverSockets[2].join("room2");
-        const sockets = await io.in("room1").fetchSockets();
-        expect(sockets.length).to.eql(2);
-      });
+    it("returns all socket instances in the given room", async () => {
+      serverSockets[0].join(["room1", "room2"]);
+      serverSockets[1].join("room1");
+      serverSockets[2].join("room2");
+      const sockets = await io.in("room1").fetchSockets();
+      expect(sockets.length).to.eql(2);
+    });
 
-      it("works with a custom adapter", async () => {
-        io.adapter(DummyAdapter);
-        const sockets = await io.fetchSockets();
-        expect(sockets.length).to.eql(1);
-        const remoteSocket = sockets[0];
-        expect(remoteSocket.id).to.eql("42");
-        expect(remoteSocket.rooms).to.contain("42", "room1");
-        expect(remoteSocket.data).to.eql({ username: "john" });
+    it("works with a custom adapter", async () => {
+      io.adapter(DummyAdapter);
+      const sockets = await io.fetchSockets();
+      expect(sockets.length).to.eql(1);
+      const remoteSocket = sockets[0];
+      expect(remoteSocket.id).to.eql("42");
+      expect(remoteSocket.rooms).to.contain("42", "room1");
+      expect(remoteSocket.data).to.eql({ username: "john" });
+    });
+  });
+
+  describe("socketsJoin", () => {
+    it("makes all socket instances join the given room", () => {
+      io.socketsJoin("room1");
+      serverSockets.forEach((socket) => {
+        expect(socket.rooms).to.contain("room1");
       });
     });
 
-    describe("socketsJoin", () => {
-      it("makes all socket instances join the given room", () => {
-        io.socketsJoin("room1");
-        serverSockets.forEach((socket) => {
-          expect(socket.rooms).to.contain("room1");
-        });
-      });
+    it("makes all socket instances in a room join the given room", () => {
+      serverSockets[0].join(["room1", "room2"]);
+      serverSockets[1].join("room1");
+      serverSockets[2].join("room2");
+      io.in("room1").socketsJoin("room3");
+      expect(serverSockets[0].rooms).to.contain("room3");
+      expect(serverSockets[1].rooms).to.contain("room3");
+      expect(serverSockets[2].rooms).to.not.contain("room3");
+    });
+  });
 
-      it("makes all socket instances in a room join the given room", () => {
-        serverSockets[0].join(["room1", "room2"]);
-        serverSockets[1].join("room1");
-        serverSockets[2].join("room2");
-        io.in("room1").socketsJoin("room3");
-        expect(serverSockets[0].rooms).to.contain("room3");
-        expect(serverSockets[1].rooms).to.contain("room3");
-        expect(serverSockets[2].rooms).to.not.contain("room3");
-      });
+  describe("socketsLeave", () => {
+    it("makes all socket instances leave the given room", () => {
+      serverSockets[0].join(["room1", "room2"]);
+      serverSockets[1].join("room1");
+      serverSockets[2].join("room2");
+      io.socketsLeave("room1");
+      expect(serverSockets[0].rooms).to.contain("room2");
+      expect(serverSockets[0].rooms).to.not.contain("room1");
+      expect(serverSockets[1].rooms).to.not.contain("room1");
     });
 
-    describe("socketsLeave", () => {
-      it("makes all socket instances leave the given room", () => {
-        serverSockets[0].join(["room1", "room2"]);
-        serverSockets[1].join("room1");
-        serverSockets[2].join("room2");
-        io.socketsLeave("room1");
-        expect(serverSockets[0].rooms).to.contain("room2");
-        expect(serverSockets[0].rooms).to.not.contain("room1");
-        expect(serverSockets[1].rooms).to.not.contain("room1");
-      });
+    it("makes all socket instances in a room leave the given room", () => {
+      serverSockets[0].join(["room1", "room2"]);
+      serverSockets[1].join("room1");
+      serverSockets[2].join("room2");
+      io.in("room2").socketsLeave("room1");
+      expect(serverSockets[0].rooms).to.contain("room2");
+      expect(serverSockets[0].rooms).to.not.contain("room1");
+      expect(serverSockets[1].rooms).to.contain("room1");
+    });
+  });
 
-      it("makes all socket instances in a room leave the given room", () => {
-        serverSockets[0].join(["room1", "room2"]);
-        serverSockets[1].join("room1");
-        serverSockets[2].join("room2");
-        io.in("room2").socketsLeave("room1");
-        expect(serverSockets[0].rooms).to.contain("room2");
-        expect(serverSockets[0].rooms).to.not.contain("room1");
-        expect(serverSockets[1].rooms).to.contain("room1");
-      });
+  describe("disconnectSockets", () => {
+    it("makes all socket instances disconnect", (done) => {
+      io.disconnectSockets(true);
+
+      const partialDone = createPartialDone(3, done);
+
+      clientSockets[0].on("disconnect", partialDone);
+      clientSockets[1].on("disconnect", partialDone);
+      clientSockets[2].on("disconnect", partialDone);
     });
 
-    describe("disconnectSockets", () => {
-      it("makes all socket instances disconnect", (done) => {
-        io.disconnectSockets(true);
+    it("makes all socket instances in a room disconnect", (done) => {
+      serverSockets[0].join(["room1", "room2"]);
+      serverSockets[1].join("room1");
+      serverSockets[2].join("room2");
+      io.in("room2").disconnectSockets(true);
 
-        const partialDone = createPartialDone(3, done);
-
-        clientSockets[0].on("disconnect", partialDone);
-        clientSockets[1].on("disconnect", partialDone);
-        clientSockets[2].on("disconnect", partialDone);
+      const partialDone = createPartialDone(2, () => {
+        clientSockets[1].off("disconnect");
+        done();
       });
 
-      it("makes all socket instances in a room disconnect", (done) => {
-        serverSockets[0].join(["room1", "room2"]);
-        serverSockets[1].join("room1");
-        serverSockets[2].join("room2");
-        io.in("room2").disconnectSockets(true);
-
-        const partialDone = createPartialDone(2, done, () => {
-          clientSockets[1].off("disconnect");
-        });
-
-        clientSockets[0].on("disconnect", partialDone);
-        clientSockets[1].on("disconnect", () => {
-          done(new Error("should not happen"));
-        });
-        clientSockets[2].on("disconnect", partialDone);
+      clientSockets[0].on("disconnect", partialDone);
+      clientSockets[1].on("disconnect", () => {
+        done(new Error("should not happen"));
       });
+      clientSockets[2].on("disconnect", partialDone);
     });
   });
 });

test/uws.ts

@@ -1,4 +1,8 @@
-import { App, us_socket_local_port } from "uWebSockets.js";
+import {
+  App,
+  us_socket_local_port,
+  us_listen_socket_close,
+} from "uWebSockets.js";
 import { Server } from "..";
 import { io as ioc, Socket as ClientSocket } from "socket.io-client";
 import request from "supertest";
@@ -19,6 +23,7 @@ const shouldNotHappen = (done) => () => done(new Error("should not happen"));
 
 describe("socket.io with uWebSocket.js-based engine", () => {
   let io: Server,
+    uwsSocket: any,
     port: number,
     client: ClientSocket,
     clientWSOnly: ClientSocket,
@@ -33,6 +38,7 @@ describe("socket.io with uWebSocket.js-based engine", () => {
     io.of("/custom");
 
     app.listen(0, (listenSocket) => {
+      uwsSocket = listenSocket;
       port = us_socket_local_port(listenSocket);
 
       client = ioc(`http://localhost:${port}`);
@@ -54,6 +60,8 @@ describe("socket.io with uWebSocket.js-based engine", () => {
 
   afterEach(() => {
     io.close();
+    us_listen_socket_close(uwsSocket);
+
     client.disconnect();
     clientWSOnly.disconnect();
     clientPollingOnly.disconnect();
@@ -178,6 +186,12 @@ describe("socket.io with uWebSocket.js-based engine", () => {
     io.to("room1").emit("hello");
   });
 
+  it("should not crash when socket is disconnected before the upgrade", (done) => {
+    client.on("disconnect", () => done());
+
+    io.of("/").sockets.get(client.id)!.disconnect();
+  });
+
   it("should serve static files", (done) => {
     const clientVersion = require("socket.io-client/package.json").version;
 

test/v2-compatibility.ts

@@ -0,0 +1,64 @@
+import { Server, Socket } from "..";
+import expect from "expect.js";
+import { success, getPort, waitFor } from "./support/util";
+import * as io_v2 from "socket.io-client-v2";
+
+describe("v2 compatibility", () => {
+  it("should connect if `allowEIO3` is true", (done) => {
+    const io = new Server(0, {
+      allowEIO3: true,
+    });
+
+    const clientSocket = io_v2.connect(`http://localhost:${getPort(io)}`, {
+      multiplex: false,
+    });
+
+    Promise.all([
+      waitFor(io, "connection"),
+      waitFor(clientSocket, "connect"),
+    ]).then(([socket]) => {
+      expect((socket as Socket).id).to.eql(clientSocket.id);
+
+      success(done, io, clientSocket);
+    });
+  });
+
+  it("should be able to connect to a namespace with a query", (done) => {
+    const io = new Server(0, {
+      allowEIO3: true,
+    });
+
+    const clientSocket = io_v2.connect(
+      `http://localhost:${getPort(io)}/the-namespace`,
+      {
+        multiplex: false,
+      }
+    );
+    clientSocket.query = { test: "123" };
+
+    Promise.all([
+      waitFor(io.of("/the-namespace"), "connection"),
+      waitFor(clientSocket, "connect"),
+    ]).then(([socket]) => {
+      expect((socket as Socket).handshake.auth).to.eql({ test: "123" });
+
+      success(done, io, clientSocket);
+    });
+  });
+
+  it("should not connect if `allowEIO3` is false (default)", (done) => {
+    const io = new Server(0);
+
+    const clientSocket = io_v2.connect(`http://localhost:${getPort(io)}`, {
+      multiplex: false,
+    });
+
+    clientSocket.on("connect", () => {
+      done(new Error("should not happen"));
+    });
+
+    clientSocket.on("connect_error", () => {
+      success(done, io, clientSocket);
+    });
+  });
+});