Property 'X' is missing in type but required

// Example of TS2741 error
interface User {
    name: string;
    email: string;
    age: number;
}

const user: User = {
    name: 'John',
    email: 'john@example.com'
}; // Error: Property 'age' is missing in type

interface Product {
    id: number;
    name: string;
    price: number;
    description: string;
}

// ❌ Missing 'description'
const product: Product = {
    id: 1,
    name: 'Laptop',
    price: 999
}; // Error!

interface Config {
    apiEndpoint: string;
    timeout: number;
}

// ❌ Typo: 'apiendpoint' vs 'apiEndpoint'
const config: Config = {
    apiendpoint: '/api',  // Wrong!
    timeout: 5000
};

interface Settings {
    darkMode: boolean;
    fontSize: number;
}

// ❌ 'darkMode' is string instead of boolean
const settings: Settings = {
    darkMode: 'true',  // Wrong type!
    fontSize: 14
};

interface User {
    name: string;
    email: string;
    age: number;
}

// ✅ All properties provided
const user: User = {
    name: 'John',
    email: 'john@example.com',
    age: 25
};

interface User {
    name: string;
    email: string;
    age?: number; // Optional with ?
}

// ✅ 'age' is now optional
const user: User = {
    name: 'John',
    email: 'john@example.com'
};

interface User {
    name: string;
    email: string;
    age: number;
}

// ✅ All properties become optional
const partialUser: Partial<User> = {
    name: 'John'
};

// ✅ Useful for update operations
function updateUser(id: number, updates: Partial<User>) {
    // Only update provided fields
}

updateUser(1, { email: 'new@example.com' });

interface User {
    id: number;
    name: string;
    email: string;
    password: string;
}

// ✅ Only pick specific properties
type PublicUser = Pick<User, 'id' | 'name' | 'email'>;

const publicUser: PublicUser = {
    id: 1,
    name: 'John',
    email: 'john@example.com'
}; // No password needed!

interface User {
    id: number;
    name: string;
    email: string;
    createdAt: Date;
}

// ✅ Exclude specific properties
type CreateUserInput = Omit<User, 'id' | 'createdAt'>;

const newUser: CreateUserInput = {
    name: 'John',
    email: 'john@example.com'
}; // No id or createdAt needed!

interface CardProps {
    title: string;
    description: string;
    imageUrl?: string;  // Optional
    onClick?: () => void; // Optional
}

// ✅ Only required props
<Card title="Hello" description="World" />

// ✅ With optional props
<Card
    title="Hello"
    description="World"
    imageUrl="/image.jpg"
    onClick={() => console.log('clicked')}
/>

interface FormData {
    username: string;
    email: string;
    password: string;
    confirmPassword: string;
}

// For initial empty state
const initialState: Partial<FormData> = {};

// For submission, all fields required
function submitForm(data: FormData) {
    // All fields guaranteed to exist
}

interface ApiUser {
    id: number;
    first_name: string;
    last_name: string;
    email: string;
}

interface AppUser {
    id: number;
    fullName: string;
    email: string;
}

// ✅ Transform API response to app format
function mapUser(apiUser: ApiUser): AppUser {
    return {
        id: apiUser.id,
        fullName: `${apiUser.first_name} ${apiUser.last_name}`,
        email: apiUser.email
    };
}