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: #3726

lib/client.ts

@@ -2,7 +2,8 @@ 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";

lib/index.ts

@@ -803,5 +803,7 @@ 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 };

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);
@@ -2391,8 +2388,6 @@ describe("socket.io", () => {
   });
 
   describe("middleware", () => {
-    const { Socket } = require("../dist/socket");
-
     it("should call functions", (done) => {
       const srv = createServer();
       const sio = new Server(srv);
@@ -2581,8 +2576,6 @@ describe("socket.io", () => {
   });
 
   describe("socket middleware", () => {
-    const { Socket } = require("../dist/socket");
-
     it("should call functions", (done) => {
       const srv = createServer();
       const sio = new Server(srv);