매우 간단한 로그인 로직 작성

+import { Socket } from "socket.io";
+import { ConnectionMapper } from "./connection/ConnectionMapper";
+
+export class SocketHandler {
+  private connectionMapper: ConnectionMapper;
+
+  constructor() {
+    this.connectionMapper = new ConnectionMapper();
+  }
+
+  public connected(socket: Socket) {
+    const connection = this.connectionMapper.get(socket);
+  }
+}

+import { Socket } from "socket.io";
+import { MessageHandlerRegister } from "../message/handler/MessageHandlerRegister";
+import { User } from "../user/User";
+
+export class Connection {
+  public readonly socket: Socket;
+
+  public user?: User;
+
+  constructor(socket: Socket) {
+    this.socket = socket;
+
+    MessageHandlerRegister.registerMessageHandlers(this);
+  }
+
+  public get authenticated(): boolean {
+    return this.user !== undefined;
+  }
+}

+import { Socket } from "socket.io";
+import { Connection } from "./Connection";
+
+export class ConnectionMapper {
+  private map: Map<Socket, Connection>;
+
+  constructor() {
+    this.map = new Map<Socket, Connection>();
+  }
+
+  public get(socket: Socket): Connection {
+    var value = this.map.get(socket);
+    if (value) {
+      return value;
+    }
+
+    value = new Connection(socket);
+    return value;
+  }
+
+  public close(socket: Socket): void {
+    this.map.delete(socket);
+  }
+}

-import express from 'express';
-import socketIo from 'socket.io';
-import { createServer } from 'http';
+import express from "express";
+import socketIo from "socket.io";
+import { createServer } from "http";
+import { SocketHandler } from "./SocketHandler";
 
 const PORT = 3000;
 
@@ -8,8 +9,10 @@ const app = express();
 const server = createServer(app);
 const io = new socketIo.Server(server);
 
-io.on('connection', socket => {
-  console.log('Connected.');
-})
+const handler = new SocketHandler();
 
-server.listen(PORT, () => console.log(`Listening on ${PORT}`))
+io.on("connection", (socket) => {
+  handler.connected(socket);
+});
+
+server.listen(PORT, () => console.log(`Listening on ${PORT}`));

+import { Connection } from "../../connection/Connection";
+import { User } from "../../user/User";
+import { LoginMessage } from "../types";
+import { MessageHandler } from "./MessageHandler";
+
+export class LoginHandler implements MessageHandler<LoginMessage> {
+  public handle(connection: Connection, message: LoginMessage): void {
+    connection.user = new User(message.username);
+    console.log(`User ${message.username} has logged in!`);
+  }
+}

+import { Connection } from "../../connection/Connection";
+
+export interface MessageHandler<T> {
+  handle(connection: Connection, message: T): void;
+}

+import { Connection } from "../../connection/Connection";
+import { LoginMessage } from "../types";
+import { LoginHandler } from "./LoginHandler";
+
+export class MessageHandlerRegister {
+  static registerMessageHandlers(connection: Connection) {
+    connection.socket.on("login", (message: LoginMessage) => {
+      new LoginHandler().handle(connection, message);
+    });
+  }
+}

+export interface LoginMessage {
+  username: string;
+}

+export class User {
+  public readonly username: string;
+
+  constructor(username: string) {
+    this.username = username;
+  }
+}