Interface Typescript

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

const userWithInterface: IUser = {
    name: "interface",
    age: 200,
};

interface IExtendUser extends IUser {
    role: string;
}

const user1: IExtendUser = {
    age: 200,
    name: "Extend Interface",
    role: "Admin",
};

interface IAddNumbers {
    (num1: number, num2: number): number;
}

const addNumbers: IAddNumbers = (num1, num2) => num1 + num2;

interface IRollNumbers {
    [index: number]: number;
}

const rollNumbers: IRollNumbers = [1, 4, 5];