Merge pull request #8701 from marialunatito/feature/23-singleton-ts

#23 - Typescript

Author: kontroldev

Roadmap/23 - SINGLETON/typescript/marialunatito.ts

@@ -0,0 +1,100 @@
+// Dominio
+interface IUser {
+  id: number;
+  first_name: string;
+  last_name: string;
+  email: string;
+  birthday: Date;
+}
+
+// Entidad inmutable
+class User implements IUser {
+  readonly id: number;
+  readonly first_name: string;
+  readonly last_name: string;
+  readonly email: string;
+  readonly birthday: Date;
+
+  constructor(props: IUser) {
+    this.id = props.id;
+    this.first_name = props.first_name;
+    this.last_name = props.last_name;
+    this.email = props.email;
+    this.birthday = new Date(props.birthday); // defensivo
+    Object.freeze(this); // inmutabilidad superficial
+  }
+}
+
+// Singleton: único gestor de sesiones en el proceso
+class SessionManager {
+  private static instance?: SessionManager;
+  private store = new Map<number, User>();
+
+  private constructor() {}
+
+  static getInstance(): SessionManager {
+    if (!this.instance) this.instance = new SessionManager();
+    return this.instance;
+  }
+
+  // Crea o retorna sesión existente para el user.id
+  login(userData: IUser): User {
+    const existing = this.store.get(userData.id);
+    if (existing) return existing;
+
+    const user = new User(userData);
+    this.store.set(user.id, user);
+    return user;
+  }
+
+  getById(userId: number): User | undefined {
+    return this.store.get(userId);
+  }
+
+  // true si removió, false si no existía
+  logout(userId: number): boolean {
+    return this.store.delete(userId);
+  }
+
+  // lectura segura
+  list(): ReadonlyArray<User> {
+    return [...this.store.values()];
+  }
+
+  clear(): void {
+    this.store.clear();
+  }
+}
+
+// ================== DEMO ==================
+const session = SessionManager.getInstance();
+
+const user1: IUser = {
+  id: 1,
+  first_name: "Maria",
+  last_name: "Luna",
+  birthday: new Date("2020-01-02"),
+  email: "[email protected]",
+};
+
+const user2: IUser = {
+  id: 2,
+  first_name: "Carmen",
+  last_name: "Luna",
+  birthday: new Date("2022-04-10"),
+  email: "[email protected]",
+};
+
+const s1 = session.login(user1);
+const s2 = session.login(user2);
+const s3 = session.login(user1);
+
+console.log("s1 === s2 ?", s1 === s2); // false
+console.log("s1 === s3 ?", s1 === s3); // true
+console.log("list before logout:", session.list());
+
+session.logout(2);
+console.log("list after logout:", session.list());
+
+// script for run
+// npx ts-node "Roadmap/23 - SINGLETON/typescript/marialunatito.ts"