How can I extend interfaces in TypeScript?

How can I extend interfaces in TypeScript?

In TypeScript, you can extend interfaces using the extends keyword. This allows you to create a new interface that inherits properties from an existing one.

Can you give me an example of extending an interface?

Sure! Here's a simple example:

interface Person {
    name: string;
    age: number;
}

interface Employee extends Person {
    employeeId: number;
}

In this example, Employee extends Person and adds an employeeId property.

What happens if I want to add more properties to the extended interface?

You can simply add more properties to the new interface. For instance:

interface Employee extends Person {
    employeeId: number;
    position: string;
}

Now, Employee has both employeeId and position.

Can I extend multiple interfaces at once?

Yes, you can extend multiple interfaces by separating them with commas:

interface Manager extends Person, Employee {
    department: string;
}

This way, Manager inherits properties from both Person and Employee.