//Object Literal
// const brad = {
//   name: 'Brad',
//   age: 30
// }

// console.log(brad);
// console.log(brad.age);

//Person Constructor 
function Person(name, dob){
  this.name = name; //this refers to current instance of the object we created 
  // this.age = age;
  this.birthday = new Date(dob); //Date is a core object 
  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', 36);
// const john = new Person('John', 30);

// console.log(john.age);


const brad = new Person('Brad', '9-10-1981');

console.log(brad.calculateAge());