LSP.ts

// Abstract class representing a User
abstract class User {
    // Abstract methods to be implemented by subclasses
    abstract login(): void;
    abstract logout(): void;
}

// Concrete subclass representing an AdminUser
class AdminUser extends User {
    login(): void {
        console.log("Admin user logged in.");
    }

    logout(): void {
        console.log("Admin user logged out.");
    }
}

// Concrete subclass representing a RegularUser
class RegularUser extends User {
    login(): void {
        console.log("Regular user logged in.");
    }

    logout(): void {
        console.log("Regular user logged out.");
    }
}

// Concrete subclass representing a GuestUser
class GuestUser extends User {
    login(): void {
        console.log("Guest user logged in.");
    }

    logout(): void {
        console.log("Guest user logged out.");
    }
}

// Function to manage session for an array of users
function manageSession(users: User[]): void {
    users.forEach(user => {
        user.login(); // Calling login method for each user
        // Additional session management logic can be added here...
        user.logout(); // Calling logout method for each user
    });
}

// Creating instances of AdminUser, RegularUser, and GuestUser
const admin = new AdminUser();
const regular = new RegularUser();
const guest = new GuestUser();

// Creating an array of users
const users: User[] = [admin, regular, guest];

// Managing session for the array of users
manageSession(users);