An interface defines the structure of an object, specifying what properties and methods it should have.
interface User {
id: number;
name: string;
email: string;
isActive?: boolean; // Optional property
readonly createdAt: Date; // Read-only property
}
const user: User = {
id: 1,
name: "John Doe",
email: "john@example.com",
createdAt: new Date()
};