// Person constructor
function Person(name) {
	this.name = name;
	//this.age = age;
	this.birthday = new Date(dob);
	this.calculateAge = function() {
		const diff = Date.now() - this.birthday.getTime();
		const ageDate = new Date(diff);
		return Math.abs(ageDate.getUTCFullYear() - 1970);
	}
}

//const brad = new Person('Brad');
//const john = new Person('John');

//console.log(brad);

const brad = new Person('Brad', '9-10-1981');
console.log(brad.calculateAge());