CHALLENGE 1: Create a User Type Alias
======================================

SOLUTION:

type User = {
  id: number;
  username: string;
  email: string;
  isVerified?: boolean;
};

// Create user objects using the type alias
const user1: User = {
  id: 1,
  username: "alice_wonder",
  email: "alice@example.com",
  isVerified: true
};

const user2: User = {
  id: 2,
  username: "bob_builder",
  email: "bob@example.com"
  // isVerified is optional, so it can be omitted
};

const user3: User = {
  id: 3,
  username: "charlie_brown",
  email: "charlie@example.com",
  isVerified: false
};

EXPLANATION:
- "type User = { ... }" — defines a reusable type alias
- "id: number" — required; uniquely identifies the user
- "username: string" — required; user's login name
- "email: string" — required; user's contact email
- "isVerified?: boolean" — optional; has ? to indicate it's not required

BENEFITS OF TYPE ALIASES:
- Reuse: define once, use everywhere
- Consistency: all users have the same structure
- Clarity: reads like documentation
- Easy to refactor: change the type definition in one place

TESTING:
✅ Works: { id: 1, username: "test", email: "test@ex.com" }
✅ Works: { id: 1, username: "test", email: "test@ex.com", isVerified: true }
❌ Error: { id: "1", username: "test", email: "test@ex.com" }  (id should be number)
❌ Error: { username: "test", email: "test@ex.com" }  (missing id, which is required)