greeter.ts

class Student {
	fullName : string;
	constructor(public firstName, public middleInitial, public lastName) {
		this.fullName = firstName + " " + middleInitial + " " + lastName;
	}
}

interface Person {
	firstName : string;
	lastName : string;
}


function greeter(person : Person) {
	return "Hello ," + person.firstName + " " +person.lastName;
}

var user = new Student("Jane", "M . ", "User");

document.body.innerHTML = greeter(user);