chore(release): 4.1.2

Diff: https://github.com/socketio/socket.io/compare/4.1.1...4.1.2
fix(typings): ensure compatibility with TypeScript 3.x
2026-01-11 16:08:24 -05:00 · 2021-05-17 23:17:31 +02:00 · 2021-05-17 23:15:22 +02:00 · 2021-05-17 23:14:36 +02:00 · 2021-05-12 00:04:52 +02:00 · 2021-05-11 23:59:44 +02:00
57 changed files with 2722 additions and 306 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,46 @@
+## [4.1.2](https://github.com/socketio/socket.io/compare/4.1.1...4.1.2) (2021-05-17)
+
+
+### Bug Fixes
+
+* **typings:** ensure compatibility with TypeScript 3.x ([0cb6ac9](https://github.com/socketio/socket.io/commit/0cb6ac95b49a27483b6f1b6402fa54b35f82e36f))
+* ensure compatibility with previous versions of the adapter ([a2cf248](https://github.com/socketio/socket.io/commit/a2cf2486c366cb62293101c10520c57f6984a3fc))
+
+
+## [4.1.1](https://github.com/socketio/socket.io/compare/4.1.0...4.1.1) (2021-05-11)
+
+
+### Bug Fixes
+
+* **typings:** properly type server-side events ([b84ed1e](https://github.com/socketio/socket.io/commit/b84ed1e41c9053792caf58974c5de9395bfd509f))
+* **typings:** properly type the adapter attribute ([891b187](https://github.com/socketio/socket.io/commit/891b1870e92d1ec38910f03bb839817e2d6be65a))
+
+
+# [4.1.0](https://github.com/socketio/socket.io/compare/4.0.2...4.1.0) (2021-05-11)
+
+
+### Features
+
+* add support for inter-server communication ([93cce05](https://github.com/socketio/socket.io/commit/93cce05fb3faf91f21fa71212275c776aa161107))
+* notify upon namespace creation ([499c892](https://github.com/socketio/socket.io/commit/499c89250d2db1ab7725ab2b74840e188c267c46))
+* add a "connection_error" event ([7096e98](https://github.com/socketio/engine.io/commit/7096e98a02295a62c8ea2aa56461d4875887092d), from `engine.io`)
+* add the "initial_headers" and "headers" events ([2527543](https://github.com/socketio/engine.io/commit/252754353a0e88eb036ebb3082e9d6a9a5f497db), from `engine.io`)
+
+
+### Performance Improvements
+
+* add support for the "wsPreEncoded" writing option ([dc381b7](https://github.com/socketio/socket.io/commit/dc381b72c6b2f8172001dedd84116122e4cc95b3))
+
+
+## [4.0.2](https://github.com/socketio/socket.io/compare/4.0.1...4.0.2) (2021-05-06)
+
+
+### Bug Fixes
+
+* **typings:** make "engine" attribute public ([b81ce4c](https://github.com/socketio/socket.io/commit/b81ce4c9d0b00666361498e2ba5e0d007d5860b8))
+* properly export the Socket class ([d65b6ee](https://github.com/socketio/socket.io/commit/d65b6ee84c8e91deb61c3c1385eb19afa196a909))
+
+
 ## [4.0.1](https://github.com/socketio/socket.io/compare/4.0.0...4.0.1) (2021-03-31)


--- a/client-dist/socket.io.js
+++ b/client-dist/socket.io.js
@@ -1,5 +1,5 @@
 /*!
- * Socket.IO v4.0.1
+ * Socket.IO v4.1.2
 * (c) 2014-2021 Guillermo Rauch
 * Released under the MIT License.
 */
@@ -116,21 +116,12 @@ function _typeof(obj) { "@babel/helpers - typeof"; if (typeof Symbol === "functi
 Object.defineProperty(exports, "__esModule", {
  value: true
 });
-exports.Socket = exports.io = exports.Manager = exports.protocol = void 0;
+exports.io = exports.Socket = exports.Manager = exports.protocol = void 0;

 var url_1 = __webpack_require__(/*! ./url */ "./build/url.js");

 var manager_1 = __webpack_require__(/*! ./manager */ "./build/manager.js");

-var socket_1 = __webpack_require__(/*! ./socket */ "./build/socket.js");
-
-Object.defineProperty(exports, "Socket", {
-  enumerable: true,
-  get: function get() {
-    return socket_1.Socket;
-  }
-});
-
 var debug = __webpack_require__(/*! debug */ "./node_modules/debug/src/browser.js")("socket.io-client");
 /**
 * Module exports.
@@ -151,7 +142,7 @@ function lookup(uri, opts) {
  }

  opts = opts || {};
-  var parsed = url_1.url(uri, opts.path);
+  var parsed = url_1.url(uri, opts.path || "/socket.io");
  var source = parsed.source;
  var id = parsed.id;
  var path = parsed.path;
@@ -215,6 +206,15 @@ Object.defineProperty(exports, "Manager", {
    return manager_2.Manager;
  }
 });
+
+var socket_1 = __webpack_require__(/*! ./socket */ "./build/socket.js");
+
+Object.defineProperty(exports, "Socket", {
+  enumerable: true,
+  get: function get() {
+    return socket_1.Socket;
+  }
+});
 exports["default"] = lookup;

 /***/ }),
@@ -1216,8 +1216,8 @@ var Socket = /*#__PURE__*/function (_typed_events_1$Stric) {
      this.id = id;
      this.connected = true;
      this.disconnected = false;
-      this.emitReserved("connect");
      this.emitBuffered();
+      this.emitReserved("connect");
    }
    /**
     * Emit buffered events (received and emitted).
@@ -2571,7 +2571,8 @@ var Socket = /*#__PURE__*/function (_Emitter) {
      perMessageDeflate: {
        threshold: 1024
      },
-      transportOptions: {}
+      transportOptions: {},
+      closeOnBeforeunload: true
    }, opts);
    _this.opts.path = _this.opts.path.replace(/\/$/, "") + "/";

@@ -2588,14 +2589,19 @@ var Socket = /*#__PURE__*/function (_Emitter) {
    _this.pingTimeoutTimer = null;

    if (typeof addEventListener === "function") {
-      addEventListener("beforeunload", function () {
-        if (_this.transport) {
-          // silently close the transport
-          _this.transport.removeAllListeners();
+      if (_this.opts.closeOnBeforeunload) {
+        // 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 () {
+          if (_this.transport) {
+            // silently close the transport
+            _this.transport.removeAllListeners();

-          _this.transport.close();
-        }
-      }, false);
+            _this.transport.close();
+          }
+        }, false);
+      }

      if (_this.hostname !== "localhost") {
        _this.offlineEventListener = function () {
@@ -2651,15 +2657,16 @@ var Socket = /*#__PURE__*/function (_Emitter) {
  }, {
    key: "open",
    value: function open() {
+      var _this2 = this;
+
      var transport;

      if (this.opts.rememberUpgrade && Socket.priorWebsocketSuccess && this.transports.indexOf("websocket") !== -1) {
        transport = "websocket";
      } else if (0 === this.transports.length) {
        // Emit error on next tick so it can be listened to
-        var self = this;
        setTimeout(function () {
-          self.emit("error", "No transports available");
+          _this2.emit("error", "No transports available");
        }, 0);
        return;
      } else {
@@ -2689,8 +2696,9 @@ var Socket = /*#__PURE__*/function (_Emitter) {
  }, {
    key: "setTransport",
    value: function setTransport(transport) {
+      var _this3 = this;
+
      debug("setting transport %s", transport.name);
-      var self = this;

      if (this.transport) {
        debug("clearing existing transport %s", this.transport.name);
@@ -2700,14 +2708,8 @@ var Socket = /*#__PURE__*/function (_Emitter) {

      this.transport = transport; // set up transport listeners

-      transport.on("drain", function () {
-        self.onDrain();
-      }).on("packet", function (packet) {
-        self.onPacket(packet);
-      }).on("error", function (e) {
-        self.onError(e);
-      }).on("close", function () {
-        self.onClose("transport close");
+      transport.on("drain", this.onDrain.bind(this)).on("packet", this.onPacket.bind(this)).on("error", this.onError.bind(this)).on("close", function () {
+        _this3.onClose("transport close");
      });
    }
    /**
@@ -2720,20 +2722,16 @@ var Socket = /*#__PURE__*/function (_Emitter) {
  }, {
    key: "probe",
    value: function probe(name) {
+      var _this4 = this;
+
      debug('probing transport "%s"', name);
      var transport = this.createTransport(name, {
        probe: 1
      });
      var failed = false;
-      var self = this;
      Socket.priorWebsocketSuccess = false;

-      function onTransportOpen() {
-        if (self.onlyBinaryUpgrades) {
-          var upgradeLosesBinary = !this.supportsBinary && self.transport.supportsBinary;
-          failed = failed || upgradeLosesBinary;
-        }
-
+      var onTransportOpen = function onTransportOpen() {
        if (failed) return;
        debug('probe transport "%s" opened', name);
        transport.send([{
@@ -2745,33 +2743,42 @@ var Socket = /*#__PURE__*/function (_Emitter) {

          if ("pong" === msg.type && "probe" === msg.data) {
            debug('probe transport "%s" pong', name);
-            self.upgrading = true;
-            self.emit("upgrading", transport);
+            _this4.upgrading = true;
+
+            _this4.emit("upgrading", transport);
+
            if (!transport) return;
            Socket.priorWebsocketSuccess = "websocket" === transport.name;
-            debug('pausing current transport "%s"', self.transport.name);
-            self.transport.pause(function () {
+            debug('pausing current transport "%s"', _this4.transport.name);
+
+            _this4.transport.pause(function () {
              if (failed) return;
-              if ("closed" === self.readyState) return;
+              if ("closed" === _this4.readyState) return;
              debug("changing transport and sending upgrade packet");
              cleanup();
-              self.setTransport(transport);
+
+              _this4.setTransport(transport);
+
              transport.send([{
                type: "upgrade"
              }]);
-              self.emit("upgrade", transport);
+
+              _this4.emit("upgrade", transport);
+
              transport = null;
-              self.upgrading = false;
-              self.flush();
+              _this4.upgrading = false;
+
+              _this4.flush();
            });
          } else {
            debug('probe transport "%s" failed', name);
            var err = new Error("probe error");
            err.transport = transport.name;
-            self.emit("upgradeError", err);
+
+            _this4.emit("upgradeError", err);
          }
        });
-      }
+      };

      function freezeTransport() {
        if (failed) return; // Any callback called by transport should be ignored since now
@@ -2783,13 +2790,14 @@ var Socket = /*#__PURE__*/function (_Emitter) {
      } // Handle any error that happens while probing


-      function onerror(err) {
+      var onerror = function onerror(err) {
        var error = new Error("probe error: " + err);
        error.transport = transport.name;
        freezeTransport();
        debug('probe transport "%s" failed because of error: %s', name, err);
-        self.emit("upgradeError", error);
-      }
+
+        _this4.emit("upgradeError", error);
+      };

      function onTransportClose() {
        onerror("transport closed");
@@ -2809,13 +2817,15 @@ var Socket = /*#__PURE__*/function (_Emitter) {
      } // Remove all listeners on the transport and on self


-      function cleanup() {
+      var cleanup = function cleanup() {
        transport.removeListener("open", onTransportOpen);
        transport.removeListener("error", onerror);
        transport.removeListener("close", onTransportClose);
-        self.removeListener("close", onclose);
-        self.removeListener("upgrading", onupgrade);
-      }
+
+        _this4.removeListener("close", onclose);
+
+        _this4.removeListener("upgrading", onupgrade);
+      };

      transport.once("open", onTransportOpen);
      transport.once("error", onerror);
@@ -2921,11 +2931,11 @@ var Socket = /*#__PURE__*/function (_Emitter) {
  }, {
    key: "resetPingTimeout",
    value: function resetPingTimeout() {
-      var _this2 = this;
+      var _this5 = this;

      clearTimeout(this.pingTimeoutTimer);
      this.pingTimeoutTimer = setTimeout(function () {
-        _this2.onClose("ping timeout");
+        _this5.onClose("ping timeout");
      }, this.pingInterval + this.pingTimeout);

      if (this.opts.autoUnref) {
@@ -3041,14 +3051,37 @@ var Socket = /*#__PURE__*/function (_Emitter) {
  }, {
    key: "close",
    value: function close() {
-      var self = this;
+      var _this6 = this;
+
+      var close = function close() {
+        _this6.onClose("forced close");
+
+        debug("socket closing - telling transport to close");
+
+        _this6.transport.close();
+      };
+
+      var cleanupAndClose = function cleanupAndClose() {
+        _this6.removeListener("upgrade", cleanupAndClose);
+
+        _this6.removeListener("upgradeError", cleanupAndClose);
+
+        close();
+      };
+
+      var waitForUpgrade = function waitForUpgrade() {
+        // wait for upgrade to finish since we can't send packets while pausing a transport
+        _this6.once("upgrade", cleanupAndClose);
+
+        _this6.once("upgradeError", cleanupAndClose);
+      };

      if ("opening" === this.readyState || "open" === this.readyState) {
        this.readyState = "closing";

        if (this.writeBuffer.length) {
          this.once("drain", function () {
-            if (this.upgrading) {
+            if (_this6.upgrading) {
              waitForUpgrade();
            } else {
              close();
@@ -3061,24 +3094,6 @@ var Socket = /*#__PURE__*/function (_Emitter) {
        }
      }

-      function close() {
-        self.onClose("forced close");
-        debug("socket closing - telling transport to close");
-        self.transport.close();
-      }
-
-      function cleanupAndClose() {
-        self.removeListener("upgrade", cleanupAndClose);
-        self.removeListener("upgradeError", cleanupAndClose);
-        close();
-      }
-
-      function waitForUpgrade() {
-        // wait for upgrade to finish since we can't send packets while pausing a transport
-        self.once("upgrade", cleanupAndClose);
-        self.once("upgradeError", cleanupAndClose);
-      }
-
      return this;
    }
    /**
@@ -3105,8 +3120,7 @@ var Socket = /*#__PURE__*/function (_Emitter) {
    key: "onClose",
    value: function onClose(reason, desc) {
      if ("opening" === this.readyState || "open" === this.readyState || "closing" === this.readyState) {
-        debug('socket close with reason: "%s"', reason);
-        var self = this; // clear timers
+        debug('socket close with reason: "%s"', reason); // clear timers

        clearTimeout(this.pingIntervalTimer);
        clearTimeout(this.pingTimeoutTimer); // stop event from firing again for transport
@@ -3129,8 +3143,8 @@ var Socket = /*#__PURE__*/function (_Emitter) {
        this.emit("close", reason, desc); // clean buffers after, so users can still
        // grab the buffers on `close` event

-        self.writeBuffer = [];
-        self.prevBufferLen = 0;
+        this.writeBuffer = [];
+        this.prevBufferLen = 0;
      }
    }
    /**
@@ -3494,11 +3508,7 @@ var JSONPPolling = /*#__PURE__*/function (_Polling) {

    _this.index = callbacks.length; // add callback to jsonp global

-    var self = _assertThisInitialized(_this);
-
-    callbacks.push(function (msg) {
-      self.onData(msg);
-    }); // append to query string
+    callbacks.push(_this.onData.bind(_assertThisInitialized(_this))); // append to query string

    _this.query.j = _this.index;
    return _this;
@@ -3542,7 +3552,8 @@ var JSONPPolling = /*#__PURE__*/function (_Polling) {
  }, {
    key: "doPoll",
    value: function doPoll() {
-      var self = this;
+      var _this2 = this;
+
      var script = document.createElement("script");

      if (this.script) {
@@ -3554,7 +3565,7 @@ var JSONPPolling = /*#__PURE__*/function (_Polling) {
      script.src = this.uri();

      script.onerror = function (e) {
-        self.onError("jsonp poll error", e);
+        _this2.onError("jsonp poll error", e);
      };

      var insertAt = document.getElementsByTagName("script")[0];
@@ -3587,7 +3598,8 @@ var JSONPPolling = /*#__PURE__*/function (_Polling) {
  }, {
    key: "doWrite",
    value: function doWrite(data, fn) {
-      var self = this;
+      var _this3 = this;
+
      var iframe;

      if (!this.form) {
@@ -3615,29 +3627,31 @@ var JSONPPolling = /*#__PURE__*/function (_Polling) {
        fn();
      }

-      function initIframe() {
-        if (self.iframe) {
+      var initIframe = function initIframe() {
+        if (_this3.iframe) {
          try {
-            self.form.removeChild(self.iframe);
+            _this3.form.removeChild(_this3.iframe);
          } catch (e) {
-            self.onError("jsonp polling iframe removal error", e);
+            _this3.onError("jsonp polling iframe removal error", e);
          }
        }

        try {
          // ie6 dynamic iframes with target="" support (thanks Chris Lambacher)
-          var html = '<iframe src="javascript:0" name="' + self.iframeId + '">';
+          var html = '<iframe src="javascript:0" name="' + _this3.iframeId + '">';
          iframe = document.createElement(html);
        } catch (e) {
          iframe = document.createElement("iframe");
-          iframe.name = self.iframeId;
+          iframe.name = _this3.iframeId;
          iframe.src = "javascript:0";
        }

-        iframe.id = self.iframeId;
-        self.form.appendChild(iframe);
-        self.iframe = iframe;
-      }
+        iframe.id = _this3.iframeId;
+
+        _this3.form.appendChild(iframe);
+
+        _this3.iframe = iframe;
+      };

      initIframe(); // escape \n to prevent it from being converted into \r\n by some UAs
      // double escaping is required for escaped new lines because unescaping of new lines can be done safely on server-side
@@ -3651,7 +3665,7 @@ var JSONPPolling = /*#__PURE__*/function (_Polling) {

      if (this.iframe.attachEvent) {
        this.iframe.onreadystatechange = function () {
-          if (self.iframe.readyState === "complete") {
+          if (_this3.iframe.readyState === "complete") {
            complete();
          }
        };
@@ -3800,14 +3814,15 @@ var XHR = /*#__PURE__*/function (_Polling) {
  }, {
    key: "doWrite",
    value: function doWrite(data, fn) {
+      var _this2 = this;
+
      var req = this.request({
        method: "POST",
        data: data
      });
-      var self = this;
      req.on("success", fn);
      req.on("error", function (err) {
-        self.onError("xhr post error", err);
+        _this2.onError("xhr post error", err);
      });
    }
    /**
@@ -3819,14 +3834,13 @@ var XHR = /*#__PURE__*/function (_Polling) {
  }, {
    key: "doPoll",
    value: function doPoll() {
+      var _this3 = this;
+
      debug("xhr poll");
      var req = this.request();
-      var self = this;
-      req.on("data", function (data) {
-        self.onData(data);
-      });
+      req.on("data", this.onData.bind(this));
      req.on("error", function (err) {
-        self.onError("xhr poll error", err);
+        _this3.onError("xhr poll error", err);
      });
      this.pollXhr = req;
    }
@@ -3847,20 +3861,20 @@ var Request = /*#__PURE__*/function (_Emitter) {
   * @api public
   */
  function Request(uri, opts) {
-    var _this2;
+    var _this4;

    _classCallCheck(this, Request);

-    _this2 = _super2.call(this);
-    _this2.opts = opts;
-    _this2.method = opts.method || "GET";
-    _this2.uri = uri;
-    _this2.async = false !== opts.async;
-    _this2.data = undefined !== opts.data ? opts.data : null;
+    _this4 = _super2.call(this);
+    _this4.opts = opts;
+    _this4.method = opts.method || "GET";
+    _this4.uri = uri;
+    _this4.async = false !== opts.async;
+    _this4.data = undefined !== opts.data ? opts.data : null;

-    _this2.create();
+    _this4.create();

-    return _this2;
+    return _this4;
  }
  /**
   * Creates the XHR object and sends the request.
@@ -3872,11 +3886,12 @@ var Request = /*#__PURE__*/function (_Emitter) {
  _createClass(Request, [{
    key: "create",
    value: function create() {
+      var _this5 = this;
+
      var opts = pick(this.opts, "agent", "enablesXDR", "pfx", "key", "passphrase", "cert", "ca", "ciphers", "rejectUnauthorized", "autoUnref");
      opts.xdomain = !!this.opts.xd;
      opts.xscheme = !!this.opts.xs;
      var xhr = this.xhr = new XMLHttpRequest(opts);
-      var self = this;

      try {
        debug("xhr open %s: %s", this.method, this.uri);
@@ -3915,23 +3930,23 @@ var Request = /*#__PURE__*/function (_Emitter) {

        if (this.hasXDR()) {
          xhr.onload = function () {
-            self.onLoad();
+            _this5.onLoad();
          };

          xhr.onerror = function () {
-            self.onError(xhr.responseText);
+            _this5.onError(xhr.responseText);
          };
        } else {
          xhr.onreadystatechange = function () {
            if (4 !== xhr.readyState) return;

            if (200 === xhr.status || 1223 === xhr.status) {
-              self.onLoad();
+              _this5.onLoad();
            } else {
              // make sure the `error` event handler that's user-set
              // does not throw in the same tick and gets caught here
              setTimeout(function () {
-                self.onError(typeof xhr.status === "number" ? xhr.status : 0);
+                _this5.onError(typeof xhr.status === "number" ? xhr.status : 0);
              }, 0);
            }
          };
@@ -3944,7 +3959,7 @@ var Request = /*#__PURE__*/function (_Emitter) {
        // and thus the 'error' event can only be only bound *after* this exception
        // occurs.  Therefore, also, we cannot throw here at all.
        setTimeout(function () {
-          self.onError(e);
+          _this5.onError(e);
        }, 0);
        return;
      }
@@ -4167,14 +4182,15 @@ var Polling = /*#__PURE__*/function (_Transport) {
  }, {
    key: "pause",
    value: function pause(onPause) {
-      var self = this;
+      var _this = this;
+
      this.readyState = "pausing";

-      function pause() {
+      var pause = function pause() {
        debug("paused");
-        self.readyState = "paused";
+        _this.readyState = "paused";
        onPause();
-      }
+      };

      if (this.polling || !this.writable) {
        var total = 0;
@@ -4223,23 +4239,25 @@ var Polling = /*#__PURE__*/function (_Transport) {
  }, {
    key: "onData",
    value: function onData(data) {
-      var self = this;
+      var _this2 = this;
+
      debug("polling got data %s", data);

-      var callback = function callback(packet, index, total) {
+      var callback = function callback(packet) {
        // if its the first message we consider the transport open
-        if ("opening" === self.readyState && packet.type === "open") {
-          self.onOpen();
+        if ("opening" === _this2.readyState && packet.type === "open") {
+          _this2.onOpen();
        } // if its a close packet, we close the ongoing requests


        if ("close" === packet.type) {
-          self.onClose();
+          _this2.onClose();
+
          return false;
        } // otherwise bypass onData and handle the message


-        self.onPacket(packet);
+        _this2.onPacket(packet);
      }; // decode payload


@@ -4266,14 +4284,15 @@ var Polling = /*#__PURE__*/function (_Transport) {
  }, {
    key: "doClose",
    value: function doClose() {
-      var self = this;
+      var _this3 = this;

-      function close() {
+      var close = function close() {
        debug("writing close packet");
-        self.write([{
+
+        _this3.write([{
          type: "close"
        }]);
-      }
+      };

      if ("open" === this.readyState) {
        debug("transport open - closing");
@@ -4296,14 +4315,14 @@ var Polling = /*#__PURE__*/function (_Transport) {
  }, {
    key: "write",
    value: function write(packets) {
-      var _this = this;
+      var _this4 = this;

      this.writable = false;
      parser.encodePayload(packets, function (data) {
-        _this.doWrite(data, function () {
-          _this.writable = true;
+        _this4.doWrite(data, function () {
+          _this4.writable = true;

-          _this.emit("drain");
+          _this4.emit("drain");
        });
      });
    }
@@ -4525,61 +4544,60 @@ var WS = /*#__PURE__*/function (_Transport) {
  }, {
    key: "write",
    value: function write(packets) {
-      var self = this;
+      var _this3 = this;
+
      this.writable = false; // encodePacket efficient as it uses WS framing
      // no need for encodePayload

-      var total = packets.length;
-      var i = 0;
-      var l = total;
+      var _loop = function _loop(i) {
+        var packet = packets[i];
+        var lastPacket = i === packets.length - 1;
+        parser.encodePacket(packet, _this3.supportsBinary, function (data) {
+          // always create a new object (GH-437)
+          var opts = {};

-      for (; i < l; i++) {
-        (function (packet) {
-          parser.encodePacket(packet, self.supportsBinary, function (data) {
-            // always create a new object (GH-437)
-            var opts = {};
-
-            if (!usingBrowserWebSocket) {
-              if (packet.options) {
-                opts.compress = packet.options.compress;
-              }
-
-              if (self.opts.perMessageDeflate) {
-                var len = "string" === typeof data ? Buffer.byteLength(data) : data.length;
-
-                if (len < self.opts.perMessageDeflate.threshold) {
-                  opts.compress = false;
-                }
-              }
-            } // Sometimes the websocket has already been closed but the browser didn't
-            // have a chance of informing us about it yet, in that case send will
-            // throw an error
-
-
-            try {
-              if (usingBrowserWebSocket) {
-                // TypeError is thrown when passing the second argument on Safari
-                self.ws.send(data);
-              } else {
-                self.ws.send(data, opts);
-              }
-            } catch (e) {
-              debug("websocket closed before onclose event");
+          if (!usingBrowserWebSocket) {
+            if (packet.options) {
+              opts.compress = packet.options.compress;
            }

-            --total || done();
-          });
-        })(packets[i]);
-      }
+            if (_this3.opts.perMessageDeflate) {
+              var len = "string" === typeof data ? Buffer.byteLength(data) : data.length;

-      function done() {
-        self.emit("flush"); // fake drain
-        // defer to next tick to allow Socket to clear writeBuffer
+              if (len < _this3.opts.perMessageDeflate.threshold) {
+                opts.compress = false;
+              }
+            }
+          } // Sometimes the websocket has already been closed but the browser didn't
+          // have a chance of informing us about it yet, in that case send will
+          // throw an error

-        setTimeout(function () {
-          self.writable = true;
-          self.emit("drain");
-        }, 0);
+
+          try {
+            if (usingBrowserWebSocket) {
+              // TypeError is thrown when passing the second argument on Safari
+              _this3.ws.send(data);
+            } else {
+              _this3.ws.send(data, opts);
+            }
+          } catch (e) {
+            debug("websocket closed before onclose event");
+          }
+
+          if (lastPacket) {
+            // fake drain
+            // defer to next tick to allow Socket to clear writeBuffer
+            setTimeout(function () {
+              _this3.writable = true;
+
+              _this3.emit("drain");
+            }, 0);
+          }
+        });
+      };
+
+      for (var i = 0; i < packets.length; i++) {
+        _loop(i);
      }
    }
    /**
--- a/client-dist/socket.io.js.map
+++ b/client-dist/socket.io.js.map
--- a/client-dist/socket.io.min.js
+++ b/client-dist/socket.io.min.js
--- a/client-dist/socket.io.min.js.map
+++ b/client-dist/socket.io.min.js.map
--- a/client-dist/socket.io.msgpack.min.js
+++ b/client-dist/socket.io.msgpack.min.js
--- a/client-dist/socket.io.msgpack.min.js.map
+++ b/client-dist/socket.io.msgpack.min.js.map
--- a/examples/basic-crud-application/README.md
+++ b/examples/basic-crud-application/README.md
@@ -0,0 +1,19 @@
+# Basic CRUD application with Socket.IO
+
+Please read the related [guide](https://socket.io/get-started/basic-crud-application/).
+
+## Running the frontend
+
+```
+cd angular-client
+npm install
+npm start
+```
+
+### Running the server
+
+```
+cd server
+npm install
+npm start
+```
--- a/examples/basic-crud-application/angular-client/.browserslistrc
+++ b/examples/basic-crud-application/angular-client/.browserslistrc
@@ -0,0 +1,17 @@
+# This file is used by the build system to adjust CSS and JS output to support the specified browsers below.
+# For additional information regarding the format and rule options, please see:
+# https://github.com/browserslist/browserslist#queries
+
+# For the full list of supported browsers by the Angular framework, please see:
+# https://angular.io/guide/browser-support
+
+# You can see what browsers were selected by your queries by running:
+#   npx browserslist
+
+last 1 Chrome version
+last 1 Firefox version
+last 2 Edge major versions
+last 2 Safari major versions
+last 2 iOS major versions
+Firefox ESR
+not IE 11 # Angular supports IE 11 only as an opt-in. To opt-in, remove the 'not' prefix on this line.
--- a/examples/basic-crud-application/angular-client/.editorconfig
+++ b/examples/basic-crud-application/angular-client/.editorconfig
@@ -0,0 +1,16 @@
+# Editor configuration, see https://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.ts]
+quote_type = single
+
+[*.md]
+max_line_length = off
+trim_trailing_whitespace = false
--- a/examples/basic-crud-application/angular-client/.gitignore
+++ b/examples/basic-crud-application/angular-client/.gitignore
@@ -0,0 +1,46 @@
+# See http://help.github.com/ignore-files/ for more about ignoring files.
+
+# compiled output
+/dist
+/tmp
+/out-tsc
+# Only exists if Bazel was run
+/bazel-out
+
+# dependencies
+/node_modules
+
+# profiling files
+chrome-profiler-events*.json
+speed-measure-plugin*.json
+
+# IDEs and editors
+/.idea
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# IDE - VSCode
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+.history/*
+
+# misc
+/.sass-cache
+/connect.lock
+/coverage
+/libpeerconnection.log
+npm-debug.log
+yarn-error.log
+testem.log
+/typings
+
+# System Files
+.DS_Store
+Thumbs.db
--- a/examples/basic-crud-application/angular-client/README.md
+++ b/examples/basic-crud-application/angular-client/README.md
@@ -0,0 +1,31 @@
+# Angular TodoMVC + Socket.IO
+
+This project was generated with [Angular CLI](https://github.com/angular/angular-cli) version 11.0.4.
+
+Inspired from the [TodoMVC](http://todomvc.com/) [angular example](https://github.com/tastejs/todomvc/tree/master/examples/angular2).
+
+![demo](assets/demo.gif)
+
+## Development server
+
+Run `ng serve` for a dev server. Navigate to `http://localhost:4200/`. The app will automatically reload if you change any of the source files.
+
+## Code scaffolding
+
+Run `ng generate component component-name` to generate a new component. You can also use `ng generate directive|pipe|service|class|guard|interface|enum|module`.
+
+## Build
+
+Run `ng build` to build the project. The build artifacts will be stored in the `dist/` directory. Use the `--prod` flag for a production build.
+
+## Running unit tests
+
+Run `ng test` to execute the unit tests via [Karma](https://karma-runner.github.io).
+
+## Running end-to-end tests
+
+Run `ng e2e` to execute the end-to-end tests via [Protractor](http://www.protractortest.org/).
+
+## Further help
+
+To get more help on the Angular CLI use `ng help` or go check out the [Angular CLI Overview and Command Reference](https://angular.io/cli) page.
--- a/examples/basic-crud-application/angular-client/angular.json
+++ b/examples/basic-crud-application/angular-client/angular.json
@@ -0,0 +1,128 @@
+{
+  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
+  "version": 1,
+  "newProjectRoot": "projects",
+  "projects": {
+    "angular-todomvc": {
+      "projectType": "application",
+      "schematics": {
+        "@schematics/angular:application": {
+          "strict": true
+        }
+      },
+      "root": "",
+      "sourceRoot": "src",
+      "prefix": "app",
+      "architect": {
+        "build": {
+          "builder": "@angular-devkit/build-angular:browser",
+          "options": {
+            "outputPath": "dist/angular-todomvc",
+            "index": "src/index.html",
+            "main": "src/main.ts",
+            "polyfills": "src/polyfills.ts",
+            "tsConfig": "tsconfig.app.json",
+            "aot": true,
+            "assets": [
+              "src/favicon.ico",
+              "src/assets"
+            ],
+            "styles": [
+              "src/styles.css"
+            ],
+            "scripts": []
+          },
+          "configurations": {
+            "production": {
+              "fileReplacements": [
+                {
+                  "replace": "src/environments/environment.ts",
+                  "with": "src/environments/environment.prod.ts"
+                }
+              ],
+              "optimization": true,
+              "outputHashing": "all",
+              "sourceMap": false,
+              "namedChunks": false,
+              "extractLicenses": true,
+              "vendorChunk": false,
+              "buildOptimizer": true,
+              "budgets": [
+                {
+                  "type": "initial",
+                  "maximumWarning": "500kb",
+                  "maximumError": "1mb"
+                },
+                {
+                  "type": "anyComponentStyle",
+                  "maximumWarning": "2kb",
+                  "maximumError": "4kb"
+                }
+              ]
+            }
+          }
+        },
+        "serve": {
+          "builder": "@angular-devkit/build-angular:dev-server",
+          "options": {
+            "browserTarget": "angular-todomvc:build"
+          },
+          "configurations": {
+            "production": {
+              "browserTarget": "angular-todomvc:build:production"
+            }
+          }
+        },
+        "extract-i18n": {
+          "builder": "@angular-devkit/build-angular:extract-i18n",
+          "options": {
+            "browserTarget": "angular-todomvc:build"
+          }
+        },
+        "test": {
+          "builder": "@angular-devkit/build-angular:karma",
+          "options": {
+            "main": "src/test.ts",
+            "polyfills": "src/polyfills.ts",
+            "tsConfig": "tsconfig.spec.json",
+            "karmaConfig": "karma.conf.js",
+            "assets": [
+              "src/favicon.ico",
+              "src/assets"
+            ],
+            "styles": [
+              "src/styles.css"
+            ],
+            "scripts": []
+          }
+        },
+        "lint": {
+          "builder": "@angular-devkit/build-angular:tslint",
+          "options": {
+            "tsConfig": [
+              "tsconfig.app.json",
+              "tsconfig.spec.json",
+              "e2e/tsconfig.json"
+            ],
+            "exclude": [
+              "**/node_modules/**"
+            ]
+          }
+        },
+        "e2e": {
+          "builder": "@angular-devkit/build-angular:protractor",
+          "options": {
+            "protractorConfig": "e2e/protractor.conf.js",
+            "devServerTarget": "angular-todomvc:serve"
+          },
+          "configurations": {
+            "production": {
+              "devServerTarget": "angular-todomvc:serve:production"
+            }
+          }
+        }
+      }
+    }
+  },
+  "defaultProject": "angular-todomvc"
+}
--- a/examples/basic-crud-application/angular-client/assets/demo.gif
+++ b/examples/basic-crud-application/angular-client/assets/demo.gif
--- a/examples/basic-crud-application/angular-client/e2e/protractor.conf.js
+++ b/examples/basic-crud-application/angular-client/e2e/protractor.conf.js
@@ -0,0 +1,37 @@
+// @ts-check
+// Protractor configuration file, see link for more information
+// https://github.com/angular/protractor/blob/master/lib/config.ts
+
+const { SpecReporter, StacktraceOption } = require('jasmine-spec-reporter');
+
+/**
+ * @type { import("protractor").Config }
+ */
+exports.config = {
+  allScriptsTimeout: 11000,
+  specs: [
+    './src/**/*.e2e-spec.ts'
+  ],
+  capabilities: {
+    browserName: 'chrome'
+  },
+  directConnect: true,
+  SELENIUM_PROMISE_MANAGER: false,
+  baseUrl: 'http://localhost:4200/',
+  framework: 'jasmine',
+  jasmineNodeOpts: {
+    showColors: true,
+    defaultTimeoutInterval: 30000,
+    print: function() {}
+  },
+  onPrepare() {
+    require('ts-node').register({
+      project: require('path').join(__dirname, './tsconfig.json')
+    });
+    jasmine.getEnv().addReporter(new SpecReporter({
+      spec: {
+        displayStacktrace: StacktraceOption.PRETTY
+      }
+    }));
+  }
+};
--- a/examples/basic-crud-application/angular-client/e2e/src/app.e2e-spec.ts
+++ b/examples/basic-crud-application/angular-client/e2e/src/app.e2e-spec.ts
@@ -0,0 +1,23 @@
+import { AppPage } from './app.po';
+import { browser, logging } from 'protractor';
+
+describe('workspace-project App', () => {
+  let page: AppPage;
+
+  beforeEach(() => {
+    page = new AppPage();
+  });
+
+  it('should display welcome message', async () => {
+    await page.navigateTo();
+    expect(await page.getTitleText()).toEqual('angular-todomvc app is running!');
+  });
+
+  afterEach(async () => {
+    // Assert that there are no errors emitted from the browser
+    const logs = await browser.manage().logs().get(logging.Type.BROWSER);
+    expect(logs).not.toContain(jasmine.objectContaining({
+      level: logging.Level.SEVERE,
+    } as logging.Entry));
+  });
+});
--- a/examples/basic-crud-application/angular-client/e2e/src/app.po.ts
+++ b/examples/basic-crud-application/angular-client/e2e/src/app.po.ts
@@ -0,0 +1,11 @@
+import { browser, by, element } from 'protractor';
+
+export class AppPage {
+  async navigateTo(): Promise<unknown> {
+    return browser.get(browser.baseUrl);
+  }
+
+  async getTitleText(): Promise<string> {
+    return element(by.css('app-root .content span')).getText();
+  }
+}
--- a/examples/basic-crud-application/angular-client/e2e/tsconfig.json
+++ b/examples/basic-crud-application/angular-client/e2e/tsconfig.json
@@ -0,0 +1,13 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../out-tsc/e2e",
+    "module": "commonjs",
+    "target": "es2018",
+    "types": [
+      "jasmine",
+      "node"
+    ]
+  }
+}
--- a/examples/basic-crud-application/angular-client/karma.conf.js
+++ b/examples/basic-crud-application/angular-client/karma.conf.js
@@ -0,0 +1,44 @@
+// Karma configuration file, see link for more information
+// https://karma-runner.github.io/1.0/config/configuration-file.html
+
+module.exports = function (config) {
+  config.set({
+    basePath: '',
+    frameworks: ['jasmine', '@angular-devkit/build-angular'],
+    plugins: [
+      require('karma-jasmine'),
+      require('karma-chrome-launcher'),
+      require('karma-jasmine-html-reporter'),
+      require('karma-coverage'),
+      require('@angular-devkit/build-angular/plugins/karma')
+    ],
+    client: {
+      jasmine: {
+        // you can add configuration options for Jasmine here
+        // the possible options are listed at https://jasmine.github.io/api/edge/Configuration.html
+        // for example, you can disable the random execution with `random: false`
+        // or set a specific seed with `seed: 4321`
+      },
+      clearContext: false // leave Jasmine Spec Runner output visible in browser
+    },
+    jasmineHtmlReporter: {
+      suppressAll: true // removes the duplicated traces
+    },
+    coverageReporter: {
+      dir: require('path').join(__dirname, './coverage/angular-todomvc'),
+      subdir: '.',
+      reporters: [
+        { type: 'html' },
+        { type: 'text-summary' }
+      ]
+    },
+    reporters: ['progress', 'kjhtml'],
+    port: 9876,
+    colors: true,
+    logLevel: config.LOG_INFO,
+    autoWatch: true,
+    browsers: ['Chrome'],
+    singleRun: false,
+    restartOnFileChange: true
+  });
+};
--- a/examples/basic-crud-application/angular-client/package.json
+++ b/examples/basic-crud-application/angular-client/package.json
@@ -0,0 +1,46 @@
+{
+  "name": "angular-todomvc",
+  "version": "0.0.0",
+  "scripts": {
+    "ng": "ng",
+    "start": "ng serve",
+    "build": "ng build",
+    "test": "ng test",
+    "lint": "ng lint",
+    "e2e": "ng e2e"
+  },
+  "private": true,
+  "dependencies": {
+    "@angular/animations": "~11.0.4",
+    "@angular/common": "~11.0.4",
+    "@angular/compiler": "~11.0.4",
+    "@angular/core": "~11.0.4",
+    "@angular/forms": "~11.0.4",
+    "@angular/platform-browser": "~11.0.4",
+    "@angular/platform-browser-dynamic": "~11.0.4",
+    "@angular/router": "~11.0.4",
+    "rxjs": "~6.6.0",
+    "socket.io-client": "^4.0.0",
+    "tslib": "^2.0.0",
+    "zone.js": "~0.10.2"
+  },
+  "devDependencies": {
+    "@angular-devkit/build-angular": "~0.1100.4",
+    "@angular/cli": "~11.0.4",
+    "@angular/compiler-cli": "~11.0.4",
+    "@types/jasmine": "~3.6.0",
+    "@types/node": "^12.11.1",
+    "codelyzer": "^6.0.0",
+    "jasmine-core": "~3.6.0",
+    "jasmine-spec-reporter": "~5.0.0",
+    "karma": "~5.1.0",
+    "karma-chrome-launcher": "~3.1.0",
+    "karma-coverage": "~2.0.3",
+    "karma-jasmine": "~4.0.0",
+    "karma-jasmine-html-reporter": "^1.5.0",
+    "protractor": "~7.0.0",
+    "ts-node": "~8.3.0",
+    "tslint": "~6.1.0",
+    "typescript": "~4.0.2"
+  }
+}
--- a/examples/basic-crud-application/angular-client/src/app/app.component.css
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.css
--- a/examples/basic-crud-application/angular-client/src/app/app.component.html
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.html
@@ -0,0 +1,23 @@
+<section class="todoapp">
+  <header class="header">
+    <h1>todos</h1>
+    <input class="new-todo" placeholder="What needs to be done?" autofocus="" [(ngModel)]="newTodoText" (keyup.enter)="addTodo()">
+  </header>
+  <section class="main" *ngIf="todoStore.todos.length > 0">
+    <input id="toggle-all" class="toggle-all" type="checkbox" *ngIf="todoStore.todos.length" #toggleall [checked]="todoStore.allCompleted()" (click)="todoStore.setAllTo(toggleall.checked)">
+    <ul class="todo-list">
+      <li *ngFor="let todo of todoStore.todos" [class.completed]="todo.completed" [class.editing]="todo.editing">
+        <div class="view">
+          <input class="toggle" type="checkbox" (click)="toggleCompletion(todo)" [checked]="todo.completed">
+          <label (dblclick)="editTodo(todo)">{{todo.title}}</label>
+          <button class="destroy" (click)="remove(todo)"></button>
+        </div>
+        <input class="edit" *ngIf="todo.editing" [value]="todo.title" #editedtodo (blur)="stopEditing(todo, editedtodo.value)" (keyup.enter)="updateEditingTodo(todo, editedtodo.value)" (keyup.escape)="cancelEditingTodo(todo)">
+      </li>
+    </ul>
+  </section>
+  <footer class="footer" *ngIf="todoStore.todos.length > 0">
+    <span class="todo-count"><strong>{{todoStore.getRemaining().length}}</strong> {{todoStore.getRemaining().length == 1 ? 'item' : 'items'}} left</span>
+    <button class="clear-completed" *ngIf="todoStore.getCompleted().length > 0" (click)="removeCompleted()">Clear completed</button>
+  </footer>
+</section>
--- a/examples/basic-crud-application/angular-client/src/app/app.component.spec.ts
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.spec.ts
@@ -0,0 +1,31 @@
+import { TestBed } from '@angular/core/testing';
+import { AppComponent } from './app.component';
+
+describe('AppComponent', () => {
+  beforeEach(async () => {
+    await TestBed.configureTestingModule({
+      declarations: [
+        AppComponent
+      ],
+    }).compileComponents();
+  });
+
+  it('should create the app', () => {
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.componentInstance;
+    expect(app).toBeTruthy();
+  });
+
+  it(`should have as title 'angular-todomvc'`, () => {
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.componentInstance;
+    expect(app.title).toEqual('angular-todomvc');
+  });
+
+  it('should render title', () => {
+    const fixture = TestBed.createComponent(AppComponent);
+    fixture.detectChanges();
+    const compiled = fixture.nativeElement;
+    expect(compiled.querySelector('.content span').textContent).toContain('angular-todomvc app is running!');
+  });
+});
--- a/examples/basic-crud-application/angular-client/src/app/app.component.ts
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.ts
@@ -0,0 +1,59 @@
+import { Component } from '@angular/core';
+import { TodoStore, Todo } from './store';
+
+@Component({
+  selector: 'app-root',
+  templateUrl: './app.component.html',
+  styleUrls: ['./app.component.css']
+})
+export class AppComponent {
+  todoStore: TodoStore;
+  newTodoText = '';
+
+  constructor(todoStore: TodoStore) {
+    this.todoStore = todoStore;
+  }
+
+  stopEditing(todo: Todo, editedTitle: string) {
+    todo.title = editedTitle;
+    todo.editing = false;
+  }
+
+  cancelEditingTodo(todo: Todo) {
+    todo.editing = false;
+  }
+
+  updateEditingTodo(todo: Todo, editedTitle: string) {
+    editedTitle = editedTitle.trim();
+    todo.editing = false;
+
+    if (editedTitle.length === 0) {
+      return this.todoStore.remove(todo);
+    }
+
+    todo.title = editedTitle;
+  }
+
+  editTodo(todo: Todo) {
+    todo.editing = true;
+  }
+
+  removeCompleted() {
+    this.todoStore.removeCompleted();
+  }
+
+  toggleCompletion(todo: Todo) {
+    this.todoStore.toggleCompletion(todo);
+  }
+
+  remove(todo: Todo){
+    this.todoStore.remove(todo);
+  }
+
+  addTodo() {
+    if (this.newTodoText.trim().length) {
+      this.todoStore.add(this.newTodoText);
+      this.newTodoText = '';
+    }
+  }
+}
--- a/examples/basic-crud-application/angular-client/src/app/app.module.ts
+++ b/examples/basic-crud-application/angular-client/src/app/app.module.ts
@@ -0,0 +1,19 @@
+import { BrowserModule } from '@angular/platform-browser';
+import { NgModule } from '@angular/core';
+
+import { AppComponent } from './app.component';
+import { TodoStore } from './store';
+import { FormsModule } from "@angular/forms";
+
+@NgModule({
+  declarations: [
+    AppComponent
+  ],
+  imports: [
+    BrowserModule,
+    FormsModule
+  ],
+  providers: [TodoStore],
+  bootstrap: [AppComponent]
+})
+export class AppModule { }
--- a/examples/basic-crud-application/angular-client/src/app/store.ts
+++ b/examples/basic-crud-application/angular-client/src/app/store.ts
@@ -0,0 +1,140 @@
+import { io, Socket } from "socket.io-client";
+import { ClientEvents, ServerEvents } from "../../../server/lib/events";
+import { environment } from '../environments/environment';
+
+export interface Todo {
+  id: string,
+  title: string,
+  completed: boolean,
+  editing: boolean,
+  synced: boolean
+}
+
+const mapTodo = (todo: any) => {
+  return {
+    ...todo,
+    editing: false,
+    synced: true
+  }
+}
+
+export class TodoStore {
+  public todos: Array<Todo> = [];
+  private socket: Socket<ServerEvents, ClientEvents>;
+
+  constructor() {
+    this.socket = io(environment.serverUrl);
+
+    this.socket.on("connect", () => {
+      this.socket.emit("todo:list", (res) => {
+        if ("error" in res) {
+          // handle the error
+          return;
+        }
+        this.todos = res.data.map(mapTodo);
+      });
+    });
+
+    this.socket.on("todo:created", (todo) => {
+      this.todos.push(mapTodo(todo));
+    });
+
+    this.socket.on("todo:updated", (todo) => {
+      const existingTodo = this.todos.find(t => {
+        return t.id === todo.id
+      });
+      if (existingTodo) {
+        existingTodo.title = todo.title;
+        existingTodo.completed = todo.completed;
+      }
+    });
+
+    this.socket.on("todo:deleted", (id) => {
+      const index = this.todos.findIndex(t => {
+        return t.id === id
+      });
+      if (index !== -1) {
+        this.todos.splice(index, 1);
+      }
+    })
+  }
+
+  private getWithCompleted(completed: boolean) {
+    return this.todos.filter((todo: Todo) => todo.completed === completed);
+  }
+
+  allCompleted() {
+    return this.todos.length === this.getCompleted().length;
+  }
+
+  setAllTo(completed: boolean) {
+    this.todos.forEach(todo => {
+      todo.completed = completed;
+      todo.synced = false;
+      this.socket.emit("todo:update", todo, (res) => {
+        if (res && "error" in res) {
+          // handle the error
+          return;
+        }
+        todo.synced = true;
+      });
+    });
+  }
+
+  removeCompleted() {
+    this.getCompleted().forEach((todo) => {
+      this.socket.emit("todo:delete", todo.id, (res) => {
+        if (res && "error" in res) {
+          // handle the error
+        }
+      });
+    })
+    this.todos = this.getRemaining();
+  }
+
+  getRemaining() {
+    return this.getWithCompleted(false);
+  }
+
+  getCompleted() {
+    return this.getWithCompleted(true);
+  }
+
+  toggleCompletion(todo: Todo) {
+    todo.completed = !todo.completed;
+    todo.synced = false;
+    this.socket.emit("todo:update", todo, (res) => {
+      if (res && "error" in res) {
+        // handle the error
+        return;
+      }
+      todo.synced = true;
+    })
+  }
+
+  remove(todo: Todo) {
+    this.todos.splice(this.todos.indexOf(todo), 1);
+    this.socket.emit("todo:delete", todo.id, (res) => {
+      if (res && "error" in res) {
+        // handle the error
+      }
+    });
+  }
+
+  add(title: string) {
+    this.socket.emit("todo:create", { title, completed: false }, (res) => {
+      if ("error" in res) {
+        // handle the error
+        return;
+      }
+      this.todos.push({
+        id: res.data,
+        title,
+        completed: false,
+        editing: false,
+        synced: true
+      });
+    });
+  }
+}
+
--- a/examples/basic-crud-application/angular-client/src/assets/.gitkeep
+++ b/examples/basic-crud-application/angular-client/src/assets/.gitkeep
--- a/examples/basic-crud-application/angular-client/src/environments/environment.prod.ts
+++ b/examples/basic-crud-application/angular-client/src/environments/environment.prod.ts
@@ -0,0 +1,4 @@
+export const environment = {
+  production: true,
+  serverUrl: "https://my-custom-domain.com"
+};
--- a/examples/basic-crud-application/angular-client/src/environments/environment.ts
+++ b/examples/basic-crud-application/angular-client/src/environments/environment.ts
@@ -0,0 +1,17 @@
+// This file can be replaced during build by using the `fileReplacements` array.
+// `ng build --prod` replaces `environment.ts` with `environment.prod.ts`.
+// The list of file replacements can be found in `angular.json`.
+
+export const environment = {
+  production: false,
+  serverUrl: "http://localhost:3000"
+};
+
+/*
+ * For easier debugging in development mode, you can import the following file
+ * to ignore zone related error stack frames such as `zone.run`, `zoneDelegate.invokeTask`.
+ *
+ * This import should be commented out in production mode because it will have a negative impact
+ * on performance if an error is thrown.
+ */
+// import 'zone.js/dist/zone-error';  // Included with Angular CLI.
--- a/examples/basic-crud-application/angular-client/src/favicon.ico
+++ b/examples/basic-crud-application/angular-client/src/favicon.ico
--- a/examples/basic-crud-application/angular-client/src/index.html
+++ b/examples/basic-crud-application/angular-client/src/index.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>Angular Todo MVC</title>
+  <base href="/">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <link rel="icon" type="image/x-icon" href="favicon.ico">
+</head>
+<body>
+  <app-root></app-root>
+</body>
+</html>
--- a/examples/basic-crud-application/angular-client/src/main.ts
+++ b/examples/basic-crud-application/angular-client/src/main.ts
@@ -0,0 +1,12 @@
+import { enableProdMode } from '@angular/core';
+import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
+
+import { AppModule } from './app/app.module';
+import { environment } from './environments/environment';
+
+if (environment.production) {
+  enableProdMode();
+}
+
+platformBrowserDynamic().bootstrapModule(AppModule)
+  .catch(err => console.error(err));
--- a/examples/basic-crud-application/angular-client/src/polyfills.ts
+++ b/examples/basic-crud-application/angular-client/src/polyfills.ts
@@ -0,0 +1,63 @@
+/**
+ * This file includes polyfills needed by Angular and is loaded before the app.
+ * You can add your own extra polyfills to this file.
+ *
+ * This file is divided into 2 sections:
+ *   1. Browser polyfills. These are applied before loading ZoneJS and are sorted by browsers.
+ *   2. Application imports. Files imported after ZoneJS that should be loaded before your main
+ *      file.
+ *
+ * The current setup is for so-called "evergreen" browsers; the last versions of browsers that
+ * automatically update themselves. This includes Safari >= 10, Chrome >= 55 (including Opera),
+ * Edge >= 13 on the desktop, and iOS 10 and Chrome on mobile.
+ *
+ * Learn more in https://angular.io/guide/browser-support
+ */
+
+/***************************************************************************************************
+ * BROWSER POLYFILLS
+ */
+
+/** IE11 requires the following for NgClass support on SVG elements */
+// import 'classlist.js';  // Run `npm install --save classlist.js`.
+
+/**
+ * Web Animations `@angular/platform-browser/animations`
+ * Only required if AnimationBuilder is used within the application and using IE/Edge or Safari.
+ * Standard animation support in Angular DOES NOT require any polyfills (as of Angular 6.0).
+ */
+// import 'web-animations-js';  // Run `npm install --save web-animations-js`.
+
+/**
+ * By default, zone.js will patch all possible macroTask and DomEvents
+ * user can disable parts of macroTask/DomEvents patch by setting following flags
+ * because those flags need to be set before `zone.js` being loaded, and webpack
+ * will put import in the top of bundle, so user need to create a separate file
+ * in this directory (for example: zone-flags.ts), and put the following flags
+ * into that file, and then add the following code before importing zone.js.
+ * import './zone-flags';
+ *
+ * The flags allowed in zone-flags.ts are listed here.
+ *
+ * The following flags will work for all browsers.
+ *
+ * (window as any).__Zone_disable_requestAnimationFrame = true; // disable patch requestAnimationFrame
+ * (window as any).__Zone_disable_on_property = true; // disable patch onProperty such as onclick
+ * (window as any).__zone_symbol__UNPATCHED_EVENTS = ['scroll', 'mousemove']; // disable patch specified eventNames
+ *
+ *  in IE/Edge developer tools, the addEventListener will also be wrapped by zone.js
+ *  with the following flag, it will bypass `zone.js` patch for IE/Edge
+ *
+ *  (window as any).__Zone_enable_cross_context_check = true;
+ *
+ */
+
+/***************************************************************************************************
+ * Zone JS is required by default for Angular itself.
+ */
+import 'zone.js/dist/zone';  // Included with Angular CLI.
+
+
+/***************************************************************************************************
+ * APPLICATION IMPORTS
+ */
--- a/examples/basic-crud-application/angular-client/src/styles.css
+++ b/examples/basic-crud-application/angular-client/src/styles.css
@@ -0,0 +1,381 @@
+/* imported from node_modules/todomvc-app-css/index.css */
+html,
+body {
+  margin: 0;
+  padding: 0;
+}
+
+button {
+  margin: 0;
+  padding: 0;
+  border: 0;
+  background: none;
+  font-size: 100%;
+  vertical-align: baseline;
+  font-family: inherit;
+  font-weight: inherit;
+  color: inherit;
+  -webkit-appearance: none;
+  appearance: none;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+body {
+  font: 14px 'Helvetica Neue', Helvetica, Arial, sans-serif;
+  line-height: 1.4em;
+  background: #f5f5f5;
+  color: #111111;
+  min-width: 230px;
+  max-width: 550px;
+  margin: 0 auto;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  font-weight: 300;
+}
+
+:focus {
+  outline: 0;
+}
+
+.hidden {
+  display: none;
+}
+
+.todoapp {
+  background: #fff;
+  margin: 130px 0 40px 0;
+  position: relative;
+  box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.2),
+  0 25px 50px 0 rgba(0, 0, 0, 0.1);
+}
+
+.todoapp input::-webkit-input-placeholder {
+  font-style: italic;
+  font-weight: 300;
+  color: rgba(0, 0, 0, 0.4);
+}
+
+.todoapp input::-moz-placeholder {
+  font-style: italic;
+  font-weight: 300;
+  color: rgba(0, 0, 0, 0.4);
+}
+
+.todoapp input::input-placeholder {
+  font-style: italic;
+  font-weight: 300;
+  color: rgba(0, 0, 0, 0.4);
+}
+
+.todoapp h1 {
+  position: absolute;
+  top: -140px;
+  width: 100%;
+  font-size: 80px;
+  font-weight: 200;
+  text-align: center;
+  color: #b83f45;
+  -webkit-text-rendering: optimizeLegibility;
+  -moz-text-rendering: optimizeLegibility;
+  text-rendering: optimizeLegibility;
+}
+
+.new-todo,
+.edit {
+  position: relative;
+  margin: 0;
+  width: 100%;
+  font-size: 24px;
+  font-family: inherit;
+  font-weight: inherit;
+  line-height: 1.4em;
+  color: inherit;
+  padding: 6px;
+  border: 1px solid #999;
+  box-shadow: inset 0 -1px 5px 0 rgba(0, 0, 0, 0.2);
+  box-sizing: border-box;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+.new-todo {
+  padding: 16px 16px 16px 60px;
+  border: none;
+  background: rgba(0, 0, 0, 0.003);
+  box-shadow: inset 0 -2px 1px rgba(0,0,0,0.03);
+}
+
+.main {
+  position: relative;
+  z-index: 2;
+  border-top: 1px solid #e6e6e6;
+}
+
+.toggle-all {
+  width: 1px;
+  height: 1px;
+  border: none; /* Mobile Safari */
+  opacity: 0;
+  position: absolute;
+  right: 100%;
+  bottom: 100%;
+}
+
+.toggle-all + label {
+  width: 60px;
+  height: 34px;
+  font-size: 0;
+  position: absolute;
+  top: -52px;
+  left: -13px;
+  -webkit-transform: rotate(90deg);
+  transform: rotate(90deg);
+}
+
+.toggle-all + label:before {
+  content: '❯';
+  font-size: 22px;
+  color: #e6e6e6;
+  padding: 10px 27px 10px 27px;
+}
+
+.toggle-all:checked + label:before {
+  color: #737373;
+}
+
+.todo-list {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+
+.todo-list li {
+  position: relative;
+  font-size: 24px;
+  border-bottom: 1px solid #ededed;
+}
+
+.todo-list li:last-child {
+  border-bottom: none;
+}
+
+.todo-list li.editing {
+  border-bottom: none;
+  padding: 0;
+}
+
+.todo-list li.editing .edit {
+  display: block;
+  width: calc(100% - 43px);
+  padding: 12px 16px;
+  margin: 0 0 0 43px;
+}
+
+.todo-list li.editing .view {
+  display: none;
+}
+
+.todo-list li .toggle {
+  text-align: center;
+  width: 40px;
+  /* auto, since non-WebKit browsers doesn't support input styling */
+  height: auto;
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  margin: auto 0;
+  border: none; /* Mobile Safari */
+  -webkit-appearance: none;
+  appearance: none;
+}
+
+.todo-list li .toggle {
+  opacity: 0;
+}
+
+.todo-list li .toggle + label {
+  /*
+    Firefox requires `#` to be escaped - https://bugzilla.mozilla.org/show_bug.cgi?id=922433
+    IE and Edge requires *everything* to be escaped to render, so we do that instead of just the `#` - https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/7157459/
+  */
+  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23ededed%22%20stroke-width%3D%223%22/%3E%3C/svg%3E');
+  background-repeat: no-repeat;
+  background-position: center left;
+}
+
+.todo-list li .toggle:checked + label {
+  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23bddad5%22%20stroke-width%3D%223%22/%3E%3Cpath%20fill%3D%22%235dc2af%22%20d%3D%22M72%2025L42%2071%2027%2056l-4%204%2020%2020%2034-52z%22/%3E%3C/svg%3E');
+}
+
+.todo-list li label {
+  word-break: break-all;
+  padding: 15px 15px 15px 60px;
+  display: block;
+  line-height: 1.2;
+  transition: color 0.4s;
+  font-weight: 400;
+  color: #4d4d4d;
+}
+
+.todo-list li.completed label {
+  color: #cdcdcd;
+  text-decoration: line-through;
+}
+
+.todo-list li .destroy {
+  display: none;
+  position: absolute;
+  top: 0;
+  right: 10px;
+  bottom: 0;
+  width: 40px;
+  height: 40px;
+  margin: auto 0;
+  font-size: 30px;
+  color: #cc9a9a;
+  margin-bottom: 11px;
+  transition: color 0.2s ease-out;
+}
+
+.todo-list li .destroy:hover {
+  color: #af5b5e;
+}
+
+.todo-list li .destroy:after {
+  content: '×';
+}
+
+.todo-list li:hover .destroy {
+  display: block;
+}
+
+.todo-list li .edit {
+  display: none;
+}
+
+.todo-list li.editing:last-child {
+  margin-bottom: -1px;
+}
+
+.footer {
+  padding: 10px 15px;
+  height: 20px;
+  text-align: center;
+  font-size: 15px;
+  border-top: 1px solid #e6e6e6;
+}
+
+.footer:before {
+  content: '';
+  position: absolute;
+  right: 0;
+  bottom: 0;
+  left: 0;
+  height: 50px;
+  overflow: hidden;
+  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2),
+  0 8px 0 -3px #f6f6f6,
+  0 9px 1px -3px rgba(0, 0, 0, 0.2),
+  0 16px 0 -6px #f6f6f6,
+  0 17px 2px -6px rgba(0, 0, 0, 0.2);
+}
+
+.todo-count {
+  float: left;
+  text-align: left;
+}
+
+.todo-count strong {
+  font-weight: 300;
+}
+
+.filters {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+  position: absolute;
+  right: 0;
+  left: 0;
+}
+
+.filters li {
+  display: inline;
+}
+
+.filters li a {
+  color: inherit;
+  margin: 3px;
+  padding: 3px 7px;
+  text-decoration: none;
+  border: 1px solid transparent;
+  border-radius: 3px;
+}
+
+.filters li a:hover {
+  border-color: rgba(175, 47, 47, 0.1);
+}
+
+.filters li a.selected {
+  border-color: rgba(175, 47, 47, 0.2);
+}
+
+.clear-completed,
+html .clear-completed:active {
+  float: right;
+  position: relative;
+  line-height: 20px;
+  text-decoration: none;
+  cursor: pointer;
+}
+
+.clear-completed:hover {
+  text-decoration: underline;
+}
+
+.info {
+  margin: 65px auto 0;
+  color: #4d4d4d;
+  font-size: 11px;
+  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
+  text-align: center;
+}
+
+.info p {
+  line-height: 1;
+}
+
+.info a {
+  color: inherit;
+  text-decoration: none;
+  font-weight: 400;
+}
+
+.info a:hover {
+  text-decoration: underline;
+}
+
+/*
+	Hack to remove background from Mobile Safari.
+	Can't use it globally since it destroys checkboxes in Firefox
+*/
+@media screen and (-webkit-min-device-pixel-ratio:0) {
+  .toggle-all,
+  .todo-list li .toggle {
+    background: none;
+  }
+
+  .todo-list li .toggle {
+    height: 40px;
+  }
+}
+
+@media (max-width: 430px) {
+  .footer {
+    height: 50px;
+  }
+
+  .filters {
+    bottom: 10px;
+  }
+}
--- a/examples/basic-crud-application/angular-client/src/test.ts
+++ b/examples/basic-crud-application/angular-client/src/test.ts
@@ -0,0 +1,25 @@
+// This file is required by karma.conf.js and loads recursively all the .spec and framework files
+
+import 'zone.js/dist/zone-testing';
+import { getTestBed } from '@angular/core/testing';
+import {
+  BrowserDynamicTestingModule,
+  platformBrowserDynamicTesting
+} from '@angular/platform-browser-dynamic/testing';
+
+declare const require: {
+  context(path: string, deep?: boolean, filter?: RegExp): {
+    keys(): string[];
+    <T>(id: string): T;
+  };
+};
+
+// First, initialize the Angular testing environment.
+getTestBed().initTestEnvironment(
+  BrowserDynamicTestingModule,
+  platformBrowserDynamicTesting()
+);
+// Then we find all the tests.
+const context = require.context('./', true, /\.spec\.ts$/);
+// And load the modules.
+context.keys().map(context);
--- a/examples/basic-crud-application/angular-client/tsconfig.app.json
+++ b/examples/basic-crud-application/angular-client/tsconfig.app.json
@@ -0,0 +1,15 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./out-tsc/app",
+    "types": []
+  },
+  "files": [
+    "src/main.ts",
+    "src/polyfills.ts"
+  ],
+  "include": [
+    "src/**/*.d.ts"
+  ]
+}
--- a/examples/basic-crud-application/angular-client/tsconfig.json
+++ b/examples/basic-crud-application/angular-client/tsconfig.json
@@ -0,0 +1,29 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "baseUrl": "./",
+    "outDir": "./dist/out-tsc",
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "sourceMap": true,
+    "declaration": false,
+    "downlevelIteration": true,
+    "experimentalDecorators": true,
+    "moduleResolution": "node",
+    "importHelpers": true,
+    "target": "es2015",
+    "module": "es2020",
+    "lib": [
+      "es2018",
+      "dom"
+    ]
+  },
+  "angularCompilerOptions": {
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  }
+}
--- a/examples/basic-crud-application/angular-client/tsconfig.spec.json
+++ b/examples/basic-crud-application/angular-client/tsconfig.spec.json
@@ -0,0 +1,18 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./out-tsc/spec",
+    "types": [
+      "jasmine"
+    ]
+  },
+  "files": [
+    "src/test.ts",
+    "src/polyfills.ts"
+  ],
+  "include": [
+    "src/**/*.spec.ts",
+    "src/**/*.d.ts"
+  ]
+}
--- a/examples/basic-crud-application/angular-client/tslint.json
+++ b/examples/basic-crud-application/angular-client/tslint.json
@@ -0,0 +1,152 @@
+{
+  "extends": "tslint:recommended",
+  "rulesDirectory": [
+    "codelyzer"
+  ],
+  "rules": {
+    "align": {
+      "options": [
+        "parameters",
+        "statements"
+      ]
+    },
+    "array-type": false,
+    "arrow-return-shorthand": true,
+    "curly": true,
+    "deprecation": {
+      "severity": "warning"
+    },
+    "eofline": true,
+    "import-blacklist": [
+      true,
+      "rxjs/Rx"
+    ],
+    "import-spacing": true,
+    "indent": {
+      "options": [
+        "spaces"
+      ]
+    },
+    "max-classes-per-file": false,
+    "max-line-length": [
+      true,
+      140
+    ],
+    "member-ordering": [
+      true,
+      {
+        "order": [
+          "static-field",
+          "instance-field",
+          "static-method",
+          "instance-method"
+        ]
+      }
+    ],
+    "no-console": [
+      true,
+      "debug",
+      "info",
+      "time",
+      "timeEnd",
+      "trace"
+    ],
+    "no-empty": false,
+    "no-inferrable-types": [
+      true,
+      "ignore-params"
+    ],
+    "no-non-null-assertion": true,
+    "no-redundant-jsdoc": true,
+    "no-switch-case-fall-through": true,
+    "no-var-requires": false,
+    "object-literal-key-quotes": [
+      true,
+      "as-needed"
+    ],
+    "quotemark": [
+      true,
+      "single"
+    ],
+    "semicolon": {
+      "options": [
+        "always"
+      ]
+    },
+    "space-before-function-paren": {
+      "options": {
+        "anonymous": "never",
+        "asyncArrow": "always",
+        "constructor": "never",
+        "method": "never",
+        "named": "never"
+      }
+    },
+    "typedef": [
+      true,
+      "call-signature"
+    ],
+    "typedef-whitespace": {
+      "options": [
+        {
+          "call-signature": "nospace",
+          "index-signature": "nospace",
+          "parameter": "nospace",
+          "property-declaration": "nospace",
+          "variable-declaration": "nospace"
+        },
+        {
+          "call-signature": "onespace",
+          "index-signature": "onespace",
+          "parameter": "onespace",
+          "property-declaration": "onespace",
+          "variable-declaration": "onespace"
+        }
+      ]
+    },
+    "variable-name": {
+      "options": [
+        "ban-keywords",
+        "check-format",
+        "allow-pascal-case"
+      ]
+    },
+    "whitespace": {
+      "options": [
+        "check-branch",
+        "check-decl",
+        "check-operator",
+        "check-separator",
+        "check-type",
+        "check-typecast"
+      ]
+    },
+    "component-class-suffix": true,
+    "contextual-lifecycle": true,
+    "directive-class-suffix": true,
+    "no-conflicting-lifecycle": true,
+    "no-host-metadata-property": true,
+    "no-input-rename": true,
+    "no-inputs-metadata-property": true,
+    "no-output-native": true,
+    "no-output-on-prefix": true,
+    "no-output-rename": true,
+    "no-outputs-metadata-property": true,
+    "template-banana-in-box": true,
+    "template-no-negated-async": true,
+    "use-lifecycle-interface": true,
+    "use-pipe-transform-interface": true,
+    "directive-selector": [
+      true,
+      "attribute",
+      "app",
+      "camelCase"
+    ],
+    "component-selector": [
+      true,
+      "element",
+      "app",
+      "kebab-case"
+    ]
+  }
+}
--- a/examples/basic-crud-application/server/lib/app.ts
+++ b/examples/basic-crud-application/server/lib/app.ts
@@ -0,0 +1,35 @@
+import { Server as HttpServer } from "http";
+import { Server, ServerOptions } from "socket.io";
+import { ClientEvents, ServerEvents } from "./events";
+import { TodoRepository } from "./todo-management/todo.repository";
+import createTodoHandlers from "./todo-management/todo.handlers";
+
+export interface Components {
+  todoRepository: TodoRepository;
+}
+
+export function createApplication(
+  httpServer: HttpServer,
+  components: Components,
+  serverOptions: Partial<ServerOptions> = {}
+): Server<ClientEvents, ServerEvents> {
+  const io = new Server<ClientEvents, ServerEvents>(httpServer, serverOptions);
+
+  const {
+    createTodo,
+    readTodo,
+    updateTodo,
+    deleteTodo,
+    listTodo,
+  } = createTodoHandlers(components);
+
+  io.on("connection", (socket) => {
+    socket.on("todo:create", createTodo);
+    socket.on("todo:read", readTodo);
+    socket.on("todo:update", updateTodo);
+    socket.on("todo:delete", deleteTodo);
+    socket.on("todo:list", listTodo);
+  });
+
+  return io;
+}
--- a/examples/basic-crud-application/server/lib/events.ts
+++ b/examples/basic-crud-application/server/lib/events.ts
@@ -0,0 +1,37 @@
+import { Todo, TodoID } from "./todo-management/todo.repository";
+import { ValidationErrorItem } from "joi";
+
+interface Error {
+  error: string;
+  errorDetails?: ValidationErrorItem[];
+}
+
+interface Success<T> {
+  data: T;
+}
+
+export type Response<T> = Error | Success<T>;
+
+export interface ServerEvents {
+  "todo:created": (todo: Todo) => void;
+  "todo:updated": (todo: Todo) => void;
+  "todo:deleted": (id: TodoID) => void;
+}
+
+export interface ClientEvents {
+  "todo:list": (callback: (res: Response<Todo[]>) => void) => void;
+
+  "todo:create": (
+    payload: Omit<Todo, "id">,
+    callback: (res: Response<TodoID>) => void
+  ) => void;
+
+  "todo:read": (id: TodoID, callback: (res: Response<Todo>) => void) => void;
+
+  "todo:update": (
+    payload: Todo,
+    callback: (res?: Response<void>) => void
+  ) => void;
+
+  "todo:delete": (id: TodoID, callback: (res?: Response<void>) => void) => void;
+}
--- a/examples/basic-crud-application/server/lib/index.ts
+++ b/examples/basic-crud-application/server/lib/index.ts
@@ -0,0 +1,19 @@
+import { createServer } from "http";
+import { createApplication } from "./app";
+import { InMemoryTodoRepository } from "./todo-management/todo.repository";
+
+const httpServer = createServer();
+
+createApplication(
+  httpServer,
+  {
+    todoRepository: new InMemoryTodoRepository(),
+  },
+  {
+    cors: {
+      origin: ["http://localhost:4200"],
+    },
+  }
+);
+
+httpServer.listen(3000);
--- a/examples/basic-crud-application/server/lib/todo-management/todo.handlers.ts
+++ b/examples/basic-crud-application/server/lib/todo-management/todo.handlers.ts
@@ -0,0 +1,159 @@
+import { Errors, mapErrorDetails, sanitizeErrorMessage } from "../util";
+import { v4 as uuid } from "uuid";
+import { Components } from "../app";
+import Joi = require("joi");
+import { Todo, TodoID } from "./todo.repository";
+import { ClientEvents, Response, ServerEvents } from "../events";
+import { Socket } from "socket.io";
+
+const idSchema = Joi.string().guid({
+  version: "uuidv4",
+});
+
+const todoSchema = Joi.object({
+  id: idSchema.alter({
+    create: (schema) => schema.forbidden(),
+    update: (schema) => schema.required(),
+  }),
+  title: Joi.string().max(256).required(),
+  completed: Joi.boolean().required(),
+});
+
+export default function (components: Components) {
+  const { todoRepository } = components;
+  return {
+    createTodo: async function (
+      payload: Omit<Todo, "id">,
+      callback: (res: Response<TodoID>) => void
+    ) {
+      // @ts-ignore
+      const socket: Socket<ClientEvents, ServerEvents> = this;
+
+      // validate the payload
+      const { error, value } = todoSchema.tailor("create").validate(payload, {
+        abortEarly: false,
+        stripUnknown: true,
+      });
+
+      if (error) {
+        return callback({
+          error: Errors.INVALID_PAYLOAD,
+          errorDetails: mapErrorDetails(error.details),
+        });
+      }
+
+      value.id = uuid();
+
+      // persist the entity
+      try {
+        await todoRepository.save(value);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      // acknowledge the creation
+      callback({
+        data: value.id,
+      });
+
+      // notify the other users
+      socket.broadcast.emit("todo:created", value);
+    },
+
+    readTodo: async function (
+      id: TodoID,
+      callback: (res: Response<Todo>) => void
+    ) {
+      const { error } = idSchema.validate(id);
+
+      if (error) {
+        return callback({
+          error: Errors.ENTITY_NOT_FOUND,
+        });
+      }
+
+      try {
+        const todo = await todoRepository.findById(id);
+        callback({
+          data: todo,
+        });
+      } catch (e) {
+        callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+    },
+
+    updateTodo: async function (
+      payload: Todo,
+      callback: (res?: Response<void>) => void
+    ) {
+      // @ts-ignore
+      const socket: Socket<ClientEvents, ServerEvents> = this;
+
+      const { error, value } = todoSchema.tailor("update").validate(payload, {
+        abortEarly: false,
+        stripUnknown: true,
+      });
+
+      if (error) {
+        return callback({
+          error: Errors.INVALID_PAYLOAD,
+          errorDetails: mapErrorDetails(error.details),
+        });
+      }
+
+      try {
+        await todoRepository.save(value);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      callback();
+      socket.broadcast.emit("todo:updated", value);
+    },
+
+    deleteTodo: async function (
+      id: TodoID,
+      callback: (res?: Response<void>) => void
+    ) {
+      // @ts-ignore
+      const socket: Socket<ClientEvents, ServerEvents> = this;
+
+      const { error } = idSchema.validate(id);
+
+      if (error) {
+        return callback({
+          error: Errors.ENTITY_NOT_FOUND,
+        });
+      }
+
+      try {
+        await todoRepository.deleteById(id);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      callback();
+      socket.broadcast.emit("todo:deleted", id);
+    },
+
+    listTodo: async function (callback: (res: Response<Todo[]>) => void) {
+      try {
+        callback({
+          data: await todoRepository.findAll(),
+        });
+      } catch (e) {
+        callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+    },
+  };
+}
--- a/examples/basic-crud-application/server/lib/todo-management/todo.repository.ts
+++ b/examples/basic-crud-application/server/lib/todo-management/todo.repository.ts
@@ -0,0 +1,49 @@
+import { Errors } from "../util";
+
+abstract class CrudRepository<T, ID> {
+  abstract findAll(): Promise<T[]>;
+  abstract findById(id: ID): Promise<T>;
+  abstract save(entity: T): Promise<void>;
+  abstract deleteById(id: ID): Promise<void>;
+}
+
+export type TodoID = string;
+
+export interface Todo {
+  id: TodoID;
+  completed: boolean;
+  title: string;
+}
+
+export abstract class TodoRepository extends CrudRepository<Todo, TodoID> {}
+
+export class InMemoryTodoRepository extends TodoRepository {
+  private readonly todos: Map<TodoID, Todo> = new Map();
+
+  findAll(): Promise<Todo[]> {
+    const entities = Array.from(this.todos.values());
+    return Promise.resolve(entities);
+  }
+
+  findById(id: TodoID): Promise<Todo> {
+    if (this.todos.has(id)) {
+      return Promise.resolve(this.todos.get(id)!);
+    } else {
+      return Promise.reject(Errors.ENTITY_NOT_FOUND);
+    }
+  }
+
+  save(entity: Todo): Promise<void> {
+    this.todos.set(entity.id, entity);
+    return Promise.resolve();
+  }
+
+  deleteById(id: TodoID): Promise<void> {
+    const deleted = this.todos.delete(id);
+    if (deleted) {
+      return Promise.resolve();
+    } else {
+      return Promise.reject(Errors.ENTITY_NOT_FOUND);
+    }
+  }
+}
--- a/examples/basic-crud-application/server/lib/util.ts
+++ b/examples/basic-crud-application/server/lib/util.ts
@@ -0,0 +1,24 @@
+import { ValidationErrorItem } from "joi";
+
+export enum Errors {
+  ENTITY_NOT_FOUND = "entity not found",
+  INVALID_PAYLOAD = "invalid payload",
+}
+
+const errorValues: string[] = Object.values(Errors);
+
+export function sanitizeErrorMessage(message: string) {
+  if (errorValues.includes(message)) {
+    return message;
+  } else {
+    return "an unknown error has occurred";
+  }
+}
+
+export function mapErrorDetails(details: ValidationErrorItem[]) {
+  return details.map((item) => ({
+    message: item.message,
+    path: item.path,
+    type: item.type,
+  }));
+}
--- a/examples/basic-crud-application/server/package.json
+++ b/examples/basic-crud-application/server/package.json
@@ -0,0 +1,36 @@
+{
+  "name": "basic-crud-server",
+  "version": "0.0.1",
+  "description": "Server for the Basic CRUD Socket.IO example",
+  "main": "dist/lib/index.js",
+  "scripts": {
+    "start": "ts-node lib/index.ts",
+    "build": "tsc",
+    "test": "nyc mocha --require ts-node/register test/**/*.ts"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/socketio/socket.io.git"
+  },
+  "author": "Damien Arrachequesne <damien.arrachequesne@gmail.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/socketio/socket.io/issues"
+  },
+  "homepage": "https://github.com/socketio/socket.io#readme",
+  "dependencies": {
+    "joi": "^17.4.0",
+    "socket.io": "^4.0.1",
+    "uuid": "^8.3.2"
+  },
+  "devDependencies": {
+    "@types/chai": "^4.2.16",
+    "@types/uuid": "^8.3.0",
+    "chai": "^4.3.4",
+    "mocha": "^8.3.2",
+    "nyc": "^15.1.0",
+    "socket.io-client": "^4.0.1",
+    "ts-node": "^9.1.1",
+    "typescript": "^4.2.4"
+  }
+}
--- a/examples/basic-crud-application/server/test/todo-management/todo.tests.ts
+++ b/examples/basic-crud-application/server/test/todo-management/todo.tests.ts
@@ -0,0 +1,309 @@
+import { createApplication } from "../../lib/app";
+import { createServer, Server } from "http";
+import {
+  InMemoryTodoRepository,
+  TodoRepository,
+} from "../../lib/todo-management/todo.repository";
+import { AddressInfo } from "net";
+import { io, Socket } from "socket.io-client";
+import { ClientEvents, ServerEvents } from "../../lib/events";
+import { expect } from "chai";
+
+const createPartialDone = (count: number, done: () => void) => {
+  let i = 0;
+  return () => {
+    if (++i === count) {
+      done();
+    }
+  };
+};
+
+describe("todo management", () => {
+  let httpServer: Server,
+    socket: Socket<ServerEvents, ClientEvents>,
+    otherSocket: Socket<ServerEvents, ClientEvents>,
+    todoRepository: TodoRepository;
+
+  beforeEach((done) => {
+    const partialDone = createPartialDone(2, done);
+
+    httpServer = createServer();
+    todoRepository = new InMemoryTodoRepository();
+
+    createApplication(httpServer, {
+      todoRepository,
+    });
+
+    httpServer.listen(() => {
+      const port = (httpServer.address() as AddressInfo).port;
+      socket = io(`http://localhost:${port}`);
+      socket.on("connect", partialDone);
+
+      otherSocket = io(`http://localhost:${port}`);
+      otherSocket.on("connect", partialDone);
+    });
+  });
+
+  afterEach(() => {
+    httpServer.close();
+    socket.disconnect();
+    otherSocket.disconnect();
+  });
+
+  describe("create todo", () => {
+    it("should create a todo entity", (done) => {
+      const partialDone = createPartialDone(2, done);
+
+      socket.emit(
+        "todo:create",
+        {
+          title: "lorem ipsum",
+          completed: false,
+        },
+        async (res) => {
+          if ("error" in res) {
+            return done(new Error("should not happen"));
+          }
+          expect(res.data).to.be.a("string");
+
+          const storedEntity = await todoRepository.findById(res.data);
+          expect(storedEntity).to.eql({
+            id: res.data,
+            title: "lorem ipsum",
+            completed: false,
+          });
+
+          partialDone();
+        }
+      );
+
+      otherSocket.on("todo:created", (todo) => {
+        expect(todo.id).to.be.a("string");
+        expect(todo.title).to.eql("lorem ipsum");
+        expect(todo.completed).to.eql(false);
+        partialDone();
+      });
+    });
+
+    it("should fail with an invalid entity", (done) => {
+      const incompleteTodo = {
+        completed: "false",
+        description: true,
+      };
+      // @ts-ignore
+      socket.emit("todo:create", incompleteTodo, (res) => {
+        if (!("error" in res)) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.error).to.eql("invalid payload");
+        expect(res.errorDetails).to.eql([
+          {
+            message: '"title" is required',
+            path: ["title"],
+            type: "any.required",
+          },
+        ]);
+        done();
+      });
+
+      otherSocket.on("todo:created", () => {
+        done(new Error("should not happen"));
+      });
+    });
+  });
+
+  describe("read todo", () => {
+    it("should return a todo entity", (done) => {
+      todoRepository.save({
+        id: "254dbf85-f5b9-4675-b913-acab5d600884",
+        title: "lorem ipsum",
+        completed: true,
+      });
+
+      socket.emit(
+        "todo:read",
+        "254dbf85-f5b9-4675-b913-acab5d600884",
+        (res) => {
+          if ("error" in res) {
+            return done(new Error("should not happen"));
+          }
+          expect(res.data.id).to.eql("254dbf85-f5b9-4675-b913-acab5d600884");
+          expect(res.data.title).to.eql("lorem ipsum");
+          expect(res.data.completed).to.eql(true);
+          done();
+        }
+      );
+    });
+
+    it("should fail with an invalid ID", (done) => {
+      socket.emit("todo:read", "123", (res) => {
+        if ("error" in res) {
+          expect(res.error).to.eql("entity not found");
+          done();
+        } else {
+          done(new Error("should not happen"));
+        }
+      });
+    });
+
+    it("should fail with an unknown entity", (done) => {
+      socket.emit(
+        "todo:read",
+        "6edcf81e-7049-40e0-8497-9cdd52414f75",
+        (res) => {
+          if ("error" in res) {
+            expect(res.error).to.eql("entity not found");
+            done();
+          } else {
+            done(new Error("should not happen"));
+          }
+        }
+      );
+    });
+  });
+
+  describe("update todo", () => {
+    it("should update a todo entity", (done) => {
+      const partialDone = createPartialDone(2, done);
+
+      todoRepository.save({
+        id: "c7790b35-6bbb-45dd-8d67-a281ca407b43",
+        title: "lorem ipsum",
+        completed: true,
+      });
+
+      socket.emit(
+        "todo:update",
+        {
+          id: "c7790b35-6bbb-45dd-8d67-a281ca407b43",
+          title: "dolor sit amet",
+          completed: true,
+        },
+        async () => {
+          const storedEntity = await todoRepository.findById(
+            "c7790b35-6bbb-45dd-8d67-a281ca407b43"
+          );
+          expect(storedEntity).to.eql({
+            id: "c7790b35-6bbb-45dd-8d67-a281ca407b43",
+            title: "dolor sit amet",
+            completed: true,
+          });
+          partialDone();
+        }
+      );
+
+      otherSocket.on("todo:updated", (todo) => {
+        expect(todo.title).to.eql("dolor sit amet");
+        expect(todo.completed).to.eql(true);
+        partialDone();
+      });
+    });
+
+    it("should fail with an invalid entity", (done) => {
+      const incompleteTodo = {
+        id: "123",
+        completed: "false",
+        description: true,
+      };
+      // @ts-ignore
+      socket.emit("todo:update", incompleteTodo, (res) => {
+        if (!(res && "error" in res)) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.error).to.eql("invalid payload");
+        expect(res.errorDetails).to.eql([
+          {
+            message: '"id" must be a valid GUID',
+            path: ["id"],
+            type: "string.guid",
+          },
+          {
+            message: '"title" is required',
+            path: ["title"],
+            type: "any.required",
+          },
+        ]);
+        done();
+      });
+
+      otherSocket.on("todo:updated", () => {
+        done(new Error("should not happen"));
+      });
+    });
+  });
+
+  describe("delete todo", () => {
+    it("should delete a todo entity", (done) => {
+      const partialDone = createPartialDone(2, done);
+      const id = "58960ab2-4e78-4ced-8079-134f12179d46";
+
+      todoRepository.save({
+        id,
+        title: "lorem ipsum",
+        completed: true,
+      });
+
+      socket.emit("todo:delete", id, async () => {
+        try {
+          await todoRepository.findById(id);
+        } catch (e) {
+          partialDone();
+        }
+      });
+
+      otherSocket.on("todo:deleted", (id) => {
+        expect(id).to.eql("58960ab2-4e78-4ced-8079-134f12179d46");
+        partialDone();
+      });
+    });
+
+    it("should fail with an invalid ID", (done) => {
+      socket.emit("todo:delete", "123", (res) => {
+        if (!(res && "error" in res)) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.error).to.eql("entity not found");
+        done();
+      });
+
+      otherSocket.on("todo:deleted", () => {
+        done(new Error("should not happen"));
+      });
+    });
+  });
+
+  describe("list todo", () => {
+    it("should return a list of entities", (done) => {
+      todoRepository.save({
+        id: "d445db6d-9d55-4ff2-88ae-bd1f81c299d2",
+        title: "lorem ipsum",
+        completed: false,
+      });
+
+      todoRepository.save({
+        id: "5f56fb59-a887-4984-93bf-eb39b4170a35",
+        title: "dolor sit amet",
+        completed: true,
+      });
+
+      socket.emit("todo:list", (res) => {
+        if ("error" in res) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.data).to.eql([
+          {
+            id: "d445db6d-9d55-4ff2-88ae-bd1f81c299d2",
+            title: "lorem ipsum",
+            completed: false,
+          },
+          {
+            id: "5f56fb59-a887-4984-93bf-eb39b4170a35",
+            title: "dolor sit amet",
+            completed: true,
+          },
+        ]);
+        done();
+      });
+    });
+  });
+});
--- a/examples/basic-crud-application/server/tsconfig.json
+++ b/examples/basic-crud-application/server/tsconfig.json
@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "outDir": "./dist",
+    "module": "commonjs",
+    "target": "es2017",
+    "strict": true
+  },
+  "include": [
+    "./lib/**/*"
+  ]
+}
--- a/lib/client.ts
+++ b/lib/client.ts
@@ -2,25 +2,40 @@ import { Decoder, Encoder, Packet, PacketType } from "socket.io-parser";
 import debugModule = require("debug");
 import url = require("url");
 import type { IncomingMessage } from "http";
-import type { Namespace, Server } from "./index";
+import type { Server } from "./index";
+import type { Namespace } from "./namespace";
 import type { EventsMap } from "./typed-events";
 import type { Socket } from "./socket";
 import type { SocketId } from "socket.io-adapter";

 const debug = debugModule("socket.io:client");

+interface WriteOptions {
+  compress?: boolean;
+  volatile?: boolean;
+  preEncoded?: boolean;
+  wsPreEncoded?: string;
+}
+
 export class Client<
  ListenEvents extends EventsMap,
-  EmitEvents extends EventsMap
+  EmitEvents extends EventsMap,
+  ServerSideEvents extends EventsMap
 > {
  public readonly conn;

  private readonly id: string;
-  private readonly server: Server<ListenEvents, EmitEvents>;
+  private readonly server: Server<ListenEvents, EmitEvents, ServerSideEvents>;
  private readonly encoder: Encoder;
  private readonly decoder: Decoder;
-  private sockets: Map<SocketId, Socket<ListenEvents, EmitEvents>> = new Map();
-  private nsps: Map<string, Socket<ListenEvents, EmitEvents>> = new Map();
+  private sockets: Map<
+    SocketId,
+    Socket<ListenEvents, EmitEvents, ServerSideEvents>
+  > = new Map();
+  private nsps: Map<
+    string,
+    Socket<ListenEvents, EmitEvents, ServerSideEvents>
+  > = new Map();
  private connectTimeout?: NodeJS.Timeout;

  /**
@@ -30,7 +45,10 @@ export class Client<
   * @param conn
   * @package
   */
-  constructor(server: Server<ListenEvents, EmitEvents>, conn: any) {
+  constructor(
+    server: Server<ListenEvents, EmitEvents, ServerSideEvents>,
+    conn: any
+  ) {
    this.server = server;
    this.conn = conn;
    this.encoder = server.encoder;
@@ -91,7 +109,11 @@ export class Client<
    this.server._checkNamespace(
      name,
      auth,
-      (dynamicNspName: Namespace<ListenEvents, EmitEvents> | false) => {
+      (
+        dynamicNspName:
+          | Namespace<ListenEvents, EmitEvents, ServerSideEvents>
+          | false
+      ) => {
        if (dynamicNspName) {
          debug("dynamic namespace %s was created", dynamicNspName);
          this.doConnect(name, auth);
@@ -149,7 +171,7 @@ export class Client<
   *
   * @private
   */
-  _remove(socket: Socket<ListenEvents, EmitEvents>): void {
+  _remove(socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>): void {
    if (this.sockets.has(socket.id)) {
      const nsp = this.sockets.get(socket.id)!.nsp.name;
      this.sockets.delete(socket.id);
@@ -179,31 +201,30 @@ export class Client<
   * @param {Object} opts
   * @private
   */
-  _packet(packet: Packet, opts?: any): void {
-    opts = opts || {};
-    const self = this;
-
-    // this writes to the actual connection
-    function writeToEngine(encodedPackets: any) {
-      // TODO clarify this.
-      if (opts.volatile && !self.conn.transport.writable) return;
-      for (let i = 0; i < encodedPackets.length; i++) {
-        self.conn.write(encodedPackets[i], { compress: opts.compress });
-      }
-    }
-
-    if ("open" === this.conn.readyState) {
-      debug("writing packet %j", packet);
-      if (!opts.preEncoded) {
-        // not broadcasting, need to encode
-        writeToEngine(this.encoder.encode(packet)); // encode, then write results to engine
-      } else {
-        // a broadcast pre-encodes a packet
-        writeToEngine(packet);
-      }
-    } else {
+  _packet(packet: Packet | any[], opts: WriteOptions = {}): void {
+    if (this.conn.readyState !== "open") {
      debug("ignoring packet write %j", packet);
+      return;
    }
+    const encodedPackets = opts.preEncoded
+      ? (packet as any[]) // previous versions of the adapter incorrectly used socket.packet() instead of writeToEngine()
+      : this.encoder.encode(packet as Packet);
+    for (const encodedPacket of encodedPackets) {
+      this.writeToEngine(encodedPacket, opts);
+    }
+  }
+
+  private writeToEngine(
+    encodedPacket: String | Buffer,
+    opts: WriteOptions
+  ): void {
+    if (opts.volatile && !this.conn.transport.writable) {
+      debug(
+        "volatile packet is discarded since the transport is not currently writable"
+      );
+      return;
+    }
+    this.conn.write(encodedPacket, opts);
  }

  /**
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -7,11 +7,7 @@ import path = require("path");
 import engine = require("engine.io");
 import { Client } from "./client";
 import { EventEmitter } from "events";
-import {
-  ExtendedError,
-  Namespace,
-  NamespaceReservedEventsMap,
-} from "./namespace";
+import { ExtendedError, Namespace, ServerReservedEventsMap } from "./namespace";
 import { ParentNamespace } from "./parent-namespace";
 import { Adapter, Room, SocketId } from "socket.io-adapter";
 import * as parser from "socket.io-parser";
@@ -26,6 +22,7 @@ import {
  DefaultEventsMap,
  EventParams,
  StrictEventEmitter,
+  EventNames,
 } from "./typed-events";

 const debug = debugModule("socket.io:server");
@@ -40,6 +37,8 @@ type ParentNspNameMatchFn = (
  fn: (err: Error | null, success: boolean) => void
 ) => void;

+type AdapterConstructor = typeof Adapter | ((nsp: Namespace) => Adapter);
+
 interface EngineOptions {
  /**
   * how many ms without a pong packet to consider the connection closed
@@ -155,7 +154,7 @@ interface ServerOptions extends EngineAttachOptions {
   * the adapter to use
   * @default the in-memory adapter (https://github.com/socketio/socket.io-adapter)
   */
-  adapter: any;
+  adapter: AdapterConstructor;
  /**
   * the parser to use
   * @default the default parser (https://github.com/socketio/socket.io-parser)
@@ -170,13 +169,29 @@ interface ServerOptions extends EngineAttachOptions {

 export class Server<
  ListenEvents extends EventsMap = DefaultEventsMap,
-  EmitEvents extends EventsMap = ListenEvents
+  EmitEvents extends EventsMap = ListenEvents,
+  ServerSideEvents extends EventsMap = DefaultEventsMap
 > extends StrictEventEmitter<
-  {},
+  ServerSideEvents,
  EmitEvents,
-  NamespaceReservedEventsMap<ListenEvents, EmitEvents>
+  ServerReservedEventsMap<ListenEvents, EmitEvents, ServerSideEvents>
 > {
-  public readonly sockets: Namespace<ListenEvents, EmitEvents>;
+  public readonly sockets: Namespace<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents
+  >;
+  /**
+   * A reference to the underlying Engine.IO server.
+   *
+   * Example:
+   *
+   * <code>
+   *   const clientsCount = io.engine.clientsCount;
+   * </code>
+   *
+   */
+  public engine: any;

  /** @private */
  readonly _parser: typeof parser;
@@ -186,16 +201,18 @@ export class Server<
  /**
   * @private
   */
-  _nsps: Map<string, Namespace<ListenEvents, EmitEvents>> = new Map();
+  _nsps: Map<
+    string,
+    Namespace<ListenEvents, EmitEvents, ServerSideEvents>
+  > = new Map();
  private parentNsps: Map<
    ParentNspNameMatchFn,
-    ParentNamespace<ListenEvents, EmitEvents>
+    ParentNamespace<ListenEvents, EmitEvents, ServerSideEvents>
  > = new Map();
-  private _adapter?: typeof Adapter;
+  private _adapter?: AdapterConstructor;
  private _serveClient: boolean;
  private opts: Partial<EngineOptions>;
  private eio;
-  private engine;
  private _path: string;
  private clientPathRegex: RegExp;

@@ -270,7 +287,9 @@ export class Server<
  _checkNamespace(
    name: string,
    auth: { [key: string]: any },
-    fn: (nsp: Namespace<ListenEvents, EmitEvents> | false) => void
+    fn: (
+      nsp: Namespace<ListenEvents, EmitEvents, ServerSideEvents> | false
+    ) => void
  ): void {
    if (this.parentNsps.size === 0) return fn(false);

@@ -285,7 +304,12 @@ export class Server<
        if (err || !allow) {
          run();
        } else {
-          fn(this.parentNsps.get(nextFn.value)!.createChild(name));
+          const namespace = this.parentNsps
+            .get(nextFn.value)!
+            .createChild(name);
+          // @ts-ignore
+          this.sockets.emitReserved("new_namespace", namespace);
+          fn(namespace);
        }
      });
    };
@@ -338,10 +362,11 @@ export class Server<
   * @return self when setting or value when getting
   * @public
   */
-  public adapter(): typeof Adapter | undefined;
-  public adapter(v: typeof Adapter): this;
-  public adapter(v?: typeof Adapter): typeof Adapter | undefined | this;
-  public adapter(v?: typeof Adapter): typeof Adapter | undefined | this {
+  public adapter(): AdapterConstructor | undefined;
+  public adapter(v: AdapterConstructor): this;
+  public adapter(
+    v?: AdapterConstructor
+  ): AdapterConstructor | undefined | this {
    if (!arguments.length) return this._adapter;
    this._adapter = v;
    for (const nsp of this._nsps.values()) {
@@ -579,8 +604,8 @@ export class Server<
   */
  public of(
    name: string | RegExp | ParentNspNameMatchFn,
-    fn?: (socket: Socket<ListenEvents, EmitEvents>) => void
-  ): Namespace<ListenEvents, EmitEvents> {
+    fn?: (socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>) => void
+  ): Namespace<ListenEvents, EmitEvents, ServerSideEvents> {
    if (typeof name === "function" || name instanceof RegExp) {
      const parentNsp = new ParentNamespace(this);
      debug("initializing parent namespace %s", parentNsp.name);
@@ -606,6 +631,10 @@ export class Server<
      debug("initializing namespace %s", name);
      nsp = new Namespace(this, name);
      this._nsps.set(name, nsp);
+      if (name !== "/") {
+        // @ts-ignore
+        this.sockets.emitReserved("new_namespace", nsp);
+      }
    }
    if (fn) nsp.on("connect", fn);
    return nsp;
@@ -639,7 +668,7 @@ export class Server<
   */
  public use(
    fn: (
-      socket: Socket<ListenEvents, EmitEvents>,
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
      next: (err?: ExtendedError) => void
    ) => void
  ): this {
@@ -676,7 +705,9 @@ export class Server<
   * @return self
   * @public
   */
-  public except(name: Room | Room[]): Server<ListenEvents, EmitEvents> {
+  public except(
+    name: Room | Room[]
+  ): Server<ListenEvents, EmitEvents, ServerSideEvents> {
    this.sockets.except(name);
    return this;
  }
@@ -703,6 +734,20 @@ export class Server<
    return this;
  }

+  /**
+   * Emit a packet to other Socket.IO servers
+   *
+   * @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 {
+    return this.sockets.serverSideEmit(ev, ...args);
+  }
+
  /**
   * Gets a list of socket ids.
   *
@@ -803,5 +848,7 @@ emitterMethods.forEach(function (fn) {

 module.exports = (srv?, opts?) => new Server(srv, opts);
 module.exports.Server = Server;
+module.exports.Namespace = Namespace;
+module.exports.Socket = Socket;

 export { Socket, ServerOptions, Namespace, BroadcastOperator, RemoteSocket };
--- a/lib/namespace.ts
+++ b/lib/namespace.ts
@@ -20,35 +20,57 @@ export interface ExtendedError extends Error {

 export interface NamespaceReservedEventsMap<
  ListenEvents extends EventsMap,
-  EmitEvents extends EventsMap
+  EmitEvents extends EventsMap,
+  ServerSideEvents extends EventsMap
 > {
-  connect: (socket: Socket<ListenEvents, EmitEvents>) => void;
-  connection: (socket: Socket<ListenEvents, EmitEvents>) => void;
+  connect: (socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>) => void;
+  connection: (
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>
+  ) => void;
 }

+export interface ServerReservedEventsMap<
+  ListenEvents,
+  EmitEvents,
+  ServerSideEvents
+> extends NamespaceReservedEventsMap<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents
+  > {
+  new_namespace: (
+    namespace: Namespace<ListenEvents, EmitEvents, ServerSideEvents>
+  ) => void;
+}
+
+export const RESERVED_EVENTS: ReadonlySet<string | Symbol> = new Set<
+  keyof ServerReservedEventsMap<never, never, never>
+>(<const>["connect", "connection", "new_namespace"]);
+
 export class Namespace<
  ListenEvents extends EventsMap = DefaultEventsMap,
-  EmitEvents extends EventsMap = ListenEvents
+  EmitEvents extends EventsMap = ListenEvents,
+  ServerSideEvents extends EventsMap = DefaultEventsMap
 > extends StrictEventEmitter<
-  {},
+  ServerSideEvents,
  EmitEvents,
-  NamespaceReservedEventsMap<ListenEvents, EmitEvents>
+  NamespaceReservedEventsMap<ListenEvents, EmitEvents, ServerSideEvents>
 > {
  public readonly name: string;
  public readonly sockets: Map<
    SocketId,
-    Socket<ListenEvents, EmitEvents>
+    Socket<ListenEvents, EmitEvents, ServerSideEvents>
  > = new Map();

  public adapter: Adapter;

  /** @private */
-  readonly server: Server<ListenEvents, EmitEvents>;
+  readonly server: Server<ListenEvents, EmitEvents, ServerSideEvents>;

  /** @private */
  _fns: Array<
    (
-      socket: Socket<ListenEvents, EmitEvents>,
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
      next: (err?: ExtendedError) => void
    ) => void
  > = [];
@@ -62,7 +84,10 @@ export class Namespace<
   * @param server instance
   * @param name
   */
-  constructor(server: Server<ListenEvents, EmitEvents>, name: string) {
+  constructor(
+    server: Server<ListenEvents, EmitEvents, ServerSideEvents>,
+    name: string
+  ) {
    super();
    this.server = server;
    this.name = name;
@@ -77,6 +102,7 @@ export class Namespace<
   * @private
   */
  _initAdapter(): void {
+    // @ts-ignore
    this.adapter = new (this.server.adapter()!)(this);
  }

@@ -88,7 +114,7 @@ export class Namespace<
   */
  public use(
    fn: (
-      socket: Socket<ListenEvents, EmitEvents>,
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
      next: (err?: ExtendedError) => void
    ) => void
  ): this {
@@ -104,7 +130,7 @@ export class Namespace<
   * @private
   */
  private run(
-    socket: Socket<ListenEvents, EmitEvents>,
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
    fn: (err: ExtendedError | null) => void
  ) {
    const fns = this._fns.slice(0);
@@ -166,10 +192,10 @@ export class Namespace<
   * @private
   */
  _add(
-    client: Client<ListenEvents, EmitEvents>,
+    client: Client<ListenEvents, EmitEvents, ServerSideEvents>,
    query,
    fn?: () => void
-  ): Socket<ListenEvents, EmitEvents> {
+  ): Socket<ListenEvents, EmitEvents, ServerSideEvents> {
    debug("adding socket to nsp %s", this.name);
    const socket = new Socket(this, client, query);
    this.run(socket, (err) => {
@@ -212,7 +238,7 @@ export class Namespace<
   *
   * @private
   */
-  _remove(socket: Socket<ListenEvents, EmitEvents>): void {
+  _remove(socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>): void {
    if (this.sockets.has(socket.id)) {
      this.sockets.delete(socket.id);
    } else {
@@ -255,6 +281,36 @@ export class Namespace<
    return this;
  }

+  /**
+   * Emit a packet to other Socket.IO servers
+   *
+   * @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`);
+    }
+    args.unshift(ev);
+    this.adapter.serverSideEmit(args);
+    return true;
+  }
+
+  /**
+   * Called when a packet is received from another Socket.IO server
+   *
+   * @param args - an array of arguments, which may include an acknowledgement callback at the end
+   *
+   * @private
+   */
+  _onServerSideEmit(args: [string, ...any[]]) {
+    super.emitUntyped.apply(this, args);
+  }
+
  /**
   * Gets a list of clients.
   *
--- a/lib/parent-namespace.ts
+++ b/lib/parent-namespace.ts
@@ -10,12 +10,15 @@ import type { BroadcastOptions } from "socket.io-adapter";

 export class ParentNamespace<
  ListenEvents extends EventsMap = DefaultEventsMap,
-  EmitEvents extends EventsMap = ListenEvents
-> extends Namespace<ListenEvents, EmitEvents> {
+  EmitEvents extends EventsMap = ListenEvents,
+  ServerSideEvents extends EventsMap = DefaultEventsMap
+> extends Namespace<ListenEvents, EmitEvents, ServerSideEvents> {
  private static count: number = 0;
-  private children: Set<Namespace<ListenEvents, EmitEvents>> = new Set();
+  private children: Set<
+    Namespace<ListenEvents, EmitEvents, ServerSideEvents>
+  > = new Set();

-  constructor(server: Server<ListenEvents, EmitEvents>) {
+  constructor(server: Server<ListenEvents, EmitEvents, ServerSideEvents>) {
    super(server, "/_" + ParentNamespace.count++);
  }

@@ -43,7 +46,9 @@ export class ParentNamespace<
    return true;
  }

-  createChild(name: string): Namespace<ListenEvents, EmitEvents> {
+  createChild(
+    name: string
+  ): Namespace<ListenEvents, EmitEvents, ServerSideEvents> {
    const namespace = new Namespace(this.server, name);
    namespace._fns = this._fns.slice(0);
    this.listeners("connect").forEach((listener) =>
--- a/lib/socket.ts
+++ b/lib/socket.ts
@@ -46,7 +46,7 @@ export interface EventEmitterReservedEventsMap {

 export const RESERVED_EVENTS: ReadonlySet<string | Symbol> = new Set<
  | ClientReservedEvents
-  | keyof NamespaceReservedEventsMap<never, never>
+  | keyof NamespaceReservedEventsMap<never, never, never>
  | keyof SocketReservedEventsMap
  | keyof EventEmitterReservedEventsMap
 >(<const>[
@@ -110,7 +110,8 @@ export interface Handshake {

 export class Socket<
  ListenEvents extends EventsMap = DefaultEventsMap,
-  EmitEvents extends EventsMap = ListenEvents
+  EmitEvents extends EventsMap = ListenEvents,
+  ServerSideEvents extends EventsMap = DefaultEventsMap
 > extends StrictEventEmitter<
  ListenEvents,
  EmitEvents,
@@ -126,7 +127,7 @@ export class Socket<
  public connected: boolean;
  public disconnected: boolean;

-  private readonly server: Server<ListenEvents, EmitEvents>;
+  private readonly server: Server<ListenEvents, EmitEvents, ServerSideEvents>;
  private readonly adapter: Adapter;
  private acks: Map<number, () => void> = new Map();
  private fns: Array<
@@ -144,8 +145,8 @@ export class Socket<
   * @package
   */
  constructor(
-    readonly nsp: Namespace<ListenEvents, EmitEvents>,
-    readonly client: Client<ListenEvents, EmitEvents>,
+    readonly nsp: Namespace<ListenEvents, EmitEvents, ServerSideEvents>,
+    readonly client: Client<ListenEvents, EmitEvents, ServerSideEvents>,
    auth: object
  ) {
    super();
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
  "name": "socket.io",
-  "version": "4.0.1",
+  "version": "4.1.2",
  "lockfileVersion": 1,
  "requires": true,
  "dependencies": {
@@ -1206,9 +1206,9 @@
      }
    },
    "engine.io": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-5.0.0.tgz",
-      "integrity": "sha512-BATIdDV3H1SrE9/u2BAotvsmjJg0t1P4+vGedImSs1lkFAtQdvk4Ev1y4LDiPF7BPWgXWEG+NDY+nLvW3UrMWw==",
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-5.1.0.tgz",
+      "integrity": "sha512-A2i4kVvOA3qezQLlMz+FayGFdqOo0LP3fYrb0VqXMDXKoXcbgM0KxcEYnsdVzOMJQErIAb1GIStRj7UWFoiqlQ==",
      "requires": {
        "accepts": "~1.3.4",
        "base64id": "2.0.0",
@@ -1220,9 +1220,9 @@
      }
    },
    "engine.io-client": {
-      "version": "5.0.1",
-      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-5.0.1.tgz",
-      "integrity": "sha512-CQtGN3YwfvbxVwpPugcsHe5rHT4KgT49CEcQppNtu9N7WxbPN0MAG27lGaem7bvtCFtGNLSL+GEqXsFSz36jTg==",
+      "version": "5.1.1",
+      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-5.1.1.tgz",
+      "integrity": "sha512-jPFpw2HLL0lhZ2KY0BpZhIJdleQcUO9W1xkIpo0h3d6s+5D6+EV/xgQw9qWOmymszv2WXef/6KUUehyxEKomlQ==",
      "dev": true,
      "requires": {
        "base64-arraybuffer": "0.1.4",
@@ -3330,21 +3330,21 @@
      }
    },
    "socket.io-adapter": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.2.0.tgz",
-      "integrity": "sha512-rG49L+FwaVEwuAdeBRq49M97YI3ElVabJPzvHT9S6a2CWhDKnjSFasvwAwSYPRhQzfn4NtDIbCaGYgOCOU/rlg=="
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.3.0.tgz",
+      "integrity": "sha512-jdIbSFRWOkaZpo5mXy8T7rXEN6qo3bOFuq4nVeX1ZS7AtFlkbk39y153xTXEIW7W94vZfhVOux1wTU88YxcM1w=="
    },
    "socket.io-client": {
-      "version": "4.0.1",
-      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.0.1.tgz",
-      "integrity": "sha512-6AkaEG5zrVuSVW294cH1chioag9i1OqnCYjKwTc3EBGXbnyb98Lw7yMa40ifLjFj3y6fsFKsd0llbUZUCRf3Qw==",
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.1.2.tgz",
+      "integrity": "sha512-RDpWJP4DQT1XeexmeDyDkm0vrFc0+bUsHDKiVGaNISJvJonhQQOMqV9Vwfg0ZpPJ27LCdan7iqTI92FRSOkFWQ==",
      "dev": true,
      "requires": {
        "@types/component-emitter": "^1.2.10",
        "backo2": "~1.0.2",
        "component-emitter": "~1.3.0",
        "debug": "~4.3.1",
-        "engine.io-client": "~5.0.0",
+        "engine.io-client": "~5.1.1",
        "parseuri": "0.0.6",
        "socket.io-parser": "~4.0.4"
      },
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
  "name": "socket.io",
-  "version": "4.0.1",
+  "version": "4.1.2",
  "description": "node.js realtime framework server",
  "keywords": [
    "realtime",
@@ -51,8 +51,8 @@
    "accepts": "~1.3.4",
    "base64id": "~2.0.0",
    "debug": "~4.3.1",
-    "engine.io": "~5.0.0",
-    "socket.io-adapter": "~2.2.0",
+    "engine.io": "~5.1.0",
+    "socket.io-adapter": "~2.3.0",
    "socket.io-parser": "~4.0.3"
  },
  "devDependencies": {
@@ -65,7 +65,7 @@
    "nyc": "^15.1.0",
    "prettier": "^2.2.0",
    "rimraf": "^3.0.2",
-    "socket.io-client": "4.0.1",
+    "socket.io-client": "4.1.2",
    "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
    "superagent": "^6.1.0",
    "supertest": "^6.0.1",
--- a/test/socket.io.test-d.ts
+++ b/test/socket.io.test-d.ts
@@ -1,8 +1,9 @@
 "use strict";
-import { Server, Socket } from "..";
+import { Namespace, Server, Socket } from "..";
 import type { DefaultEventsMap } from "../lib/typed-events";
 import { createServer } from "http";
 import { expectError, expectType } from "tsd";
+import { Adapter } from "socket.io-adapter";

 // This file is run by tsd, not mocha.

@@ -117,7 +118,9 @@ describe("server", () => {

      it("does not accept arguments of wrong types", (done) => {
        const srv = createServer();
-        const sio = new Server<BidirectionalEvents>(srv);
+        const sio = new Server<BidirectionalEvents, BidirectionalEvents, {}>(
+          srv
+        );
        expectError(sio.on("random", (a, b, c) => {}));
        srv.listen(() => {
          expectError(sio.on("wrong name", (s) => {}));
@@ -229,4 +232,69 @@ describe("server", () => {
      });
    });
  });
+
+  describe("listen and emit event maps", () => {
+    interface ClientToServerEvents {
+      helloFromClient: (message: string) => void;
+    }
+
+    interface ServerToClientEvents {
+      helloFromServer: (message: string, x: number) => void;
+    }
+
+    interface InterServerEvents {
+      helloFromServerToServer: (message: string, x: number) => void;
+    }
+
+    describe("on", () => {
+      it("infers correct types for listener parameters", () => {
+        const srv = createServer();
+        const sio = new Server<
+          ClientToServerEvents,
+          ServerToClientEvents,
+          InterServerEvents
+        >(srv);
+
+        expectType<
+          Server<ClientToServerEvents, ServerToClientEvents, InterServerEvents>
+        >(sio);
+        srv.listen(() => {
+          sio.serverSideEmit("helloFromServerToServer", "hello", 10);
+          sio
+            .of("/test")
+            .serverSideEmit("helloFromServerToServer", "hello", 10);
+
+          sio.on("helloFromServerToServer", (message, x) => {
+            expectType<string>(message);
+            expectType<number>(x);
+          });
+          sio.of("/test").on("helloFromServerToServer", (message, x) => {
+            expectType<string>(message);
+            expectType<number>(x);
+          });
+        });
+      });
+    });
+  });
+
+  describe("adapter", () => {
+    it("accepts arguments of the correct types", () => {
+      const io = new Server({
+        adapter: (nsp) => new Adapter(nsp),
+      });
+      io.adapter(Adapter);
+
+      class MyCustomAdapter extends Adapter {
+        constructor(nsp, readonly opts) {
+          super(nsp);
+        }
+      }
+      io.adapter((nsp) => new MyCustomAdapter(nsp, { test: "123" }));
+    });
+
+    it("does not accept arguments of wrong types", () => {
+      const io = new Server();
+      expectError(io.adapter((nsp) => "nope"));
+    });
+  });
 });
--- a/test/socket.io.ts
+++ b/test/socket.io.ts
@@ -1,6 +1,6 @@
 "use strict";

-import { Server, Socket } from "..";
+import { Server, Socket, Namespace } from "..";
 import { createServer } from "http";
 import fs = require("fs");
 import { join } from "path";
@@ -373,9 +373,6 @@ describe("socket.io", () => {
  });

  describe("namespaces", () => {
-    const { Socket } = require("../dist/socket");
-    const { Namespace } = require("../dist/namespace");
-
    it("should be accessible through .sockets", () => {
      const sio = new Server();
      expect(sio.sockets).to.be.a(Namespace);
@@ -815,7 +812,7 @@ describe("socket.io", () => {
      });
    });

-    it("should close a client without namespace", (done) => {
+    it("should close a client without namespace (2)", (done) => {
      const srv = createServer();
      const sio = new Server(srv, {
        connectTimeout: 100,
@@ -889,6 +886,17 @@ describe("socket.io", () => {
      });
    });

+    it("should emit an 'new_namespace' event", (done) => {
+      const sio = new Server();
+
+      sio.on("new_namespace", (namespace) => {
+        expect(namespace.name).to.eql("/nsp");
+        done();
+      });
+
+      sio.of("/nsp");
+    });
+
    describe("dynamic namespaces", () => {
      it("should allow connections to dynamic namespaces with a regex", (done) => {
        const srv = createServer();
@@ -945,6 +953,24 @@ describe("socket.io", () => {
          });
        });
      });
+
+      it("should emit an 'new_namespace' event for a dynamic namespace", (done) => {
+        const srv = createServer();
+        const sio = new Server(srv);
+        srv.listen(() => {
+          sio.of(/^\/dynamic-\d+$/);
+
+          sio.on("new_namespace", (namespace) => {
+            expect(namespace.name).to.be("/dynamic-101");
+
+            socket.disconnect();
+            srv.close();
+            done();
+          });
+
+          const socket = client(srv, "/dynamic-101");
+        });
+      });
    });
  });

@@ -958,7 +984,9 @@ describe("socket.io", () => {
          clientSocket.off("connect", init);
          clientSocket.io.engine.close();

-          clientSocket.connect();
+          process.nextTick(() => {
+            clientSocket.connect();
+          });
          clientSocket.on("connect", () => {
            done();
          });
@@ -2388,11 +2416,31 @@ describe("socket.io", () => {
        });
      });
    });
+
+    it("should pre encode a broadcast packet", (done) => {
+      const srv = createServer();
+      const sio = new Server(srv);
+
+      srv.listen(() => {
+        const clientSocket = client(srv, { multiplex: false });
+
+        sio.on("connection", (socket) => {
+          socket.conn.on("packetCreate", (packet) => {
+            expect(packet.data).to.eql('2["hello","world"]');
+            expect(packet.options.wsPreEncoded).to.eql('42["hello","world"]');
+
+            clientSocket.close();
+            sio.close();
+            done();
+          });
+
+          sio.emit("hello", "world");
+        });
+      });
+    });
  });

  describe("middleware", () => {
-    const { Socket } = require("../dist/socket");
-
    it("should call functions", (done) => {
      const srv = createServer();
      const sio = new Server(srv);
@@ -2581,8 +2629,6 @@ describe("socket.io", () => {
  });

  describe("socket middleware", () => {
-    const { Socket } = require("../dist/socket");
-
    it("should call functions", (done) => {
      const srv = createServer();
      const sio = new Server(srv);
Author	SHA1	Message	Date
Damien Arrachequesne	1633150b2b	chore(release): 4.1.2 Diff: https://github.com/socketio/socket.io/compare/4.1.1...4.1.2	2021-05-17 23:17:31 +02:00
Damien Arrachequesne	0cb6ac95b4	fix(typings): ensure compatibility with TypeScript 3.x Labeled tuple elements were added in TypeScript 4.0. Reference: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#labeled-tuple-elements Related: https://github.com/socketio/socket.io/issues/3916	2021-05-17 23:15:22 +02:00
Damien Arrachequesne	a2cf2486c3	fix: ensure compatibility with previous versions of the adapter Using `socket.io@4.1.0` with `socket.io-adapter@2.2.0` would lead to the following error: > Uncaught Error: unknown packet type NaN Because the packet would be encoded twice, resulting in "undefined". See also: - `5579d40c24` - `dc381b72c6` Related: - https://github.com/socketio/socket.io/issues/3922 - https://github.com/socketio/socket.io/issues/3927	2021-05-17 23:14:36 +02:00
Damien Arrachequesne	995f38f4cc	chore(release): 4.1.1 Diff: https://github.com/socketio/socket.io/compare/4.1.0...4.1.1	2021-05-12 00:04:52 +02:00
Damien Arrachequesne	891b1870e9	fix(typings): properly type the adapter attribute Related: https://github.com/socketio/socket.io/issues/3796	2021-05-11 23:59:44 +02:00
Damien Arrachequesne	b84ed1e41c	fix(typings): properly type server-side events See also: `93cce05fb3`	2021-05-11 23:59:18 +02:00
Damien Arrachequesne	fb6b0efec9	chore(release): 4.1.0 Diff: https://github.com/socketio/socket.io/compare/4.0.2...4.1.0	2021-05-11 09:27:52 +02:00
Damien Arrachequesne	95d9e4a42f	test: fix randomly failing test	2021-05-11 00:06:03 +02:00
Damien Arrachequesne	499c89250d	feat: notify upon namespace creation A "new_namespace" event will be emitted when a new namespace is created: ```js io.on("new_namespace", (namespace) => { // ... }); ``` This could be used for example for registering the same middleware for each namespace. See https://github.com/socketio/socket.io/issues/3851	2021-05-11 00:09:18 +02:00
Damien Arrachequesne	93cce05fb3	feat: add support for inter-server communication Syntax: ```js // server A io.serverSideEmit("hello", "world"); // server B io.on("hello", (arg) => { console.log(arg); // prints "world" }); ``` With acknowledgements: ```js // server A io.serverSideEmit("hello", "world", (err, responses) => { console.log(responses); // prints ["hi"] }); // server B io.on("hello", (arg, callback) => { callback("hi"); }); ``` This feature replaces the customHook/customRequest API from the Redis adapter: https://github.com/socketio/socket.io-redis/issues/370	2021-05-11 00:07:20 +02:00
Damien Arrachequesne	dc381b72c6	perf: add support for the "wsPreEncoded" writing option Packets that are sent to multiple clients will now be pre-encoded for the WebSocket transport (which means simply prepending "4" - which is the "message" packet type in Engine.IO). Note: buffers are not pre-encoded, since they are sent without modification over the WebSocket connection See also: `7706b123df` engine.io diff: https://github.com/socketio/engine.io/compare/5.0.0...5.1.0	2021-05-11 00:06:03 +02:00
Damien Arrachequesne	9fff03487c	chore(release): 4.0.2 Diff: https://github.com/socketio/socket.io/compare/4.0.1...4.0.2	2021-05-06 14:38:26 +02:00
Damien Arrachequesne	b81ce4c9d0	fix(typings): make "engine" attribute public	2021-05-06 14:36:25 +02:00
Damien Arrachequesne	d65b6ee84c	fix: properly export the Socket class Before this change, `require("socket.io").Socket` would return "undefined". Note: having access to the Socket class allows users to modify its prototype. Related: https://github.com/socketio/socket.io/issues/3726	2021-05-06 14:36:12 +02:00
Damien Arrachequesne	3665aada47	docs(examples): basic CRUD application See also: https://socket.io/get-started/basic-crud-application/	2021-04-23 00:08:18 +02:00