constructor functions

constructor.js

'use strict';

// constructor functions

// 1. New {} is created
// 2. function is called, this = {}
// 3. {} linked to prototype
// 4. function automatically return {}

const Person = function (firstName, birthYear) {
  // instance properties
  this.firstName = firstName;
  this.birthYear = birthYear;

  // NEVER CREATE A METHOD INSIDE A CONSTRUCTOR fX
  // Performance issues
  //   this calcAge = function() {
  //     console.log(2037 - this.birthYear);
  //   }
};

const jonas = new Person('Jonas', 1991);
console.log(jonas);

const zelda = new Person('Zelda', 2022);
const grace = new Person('Grace', 1964);

console.log(zelda, grace);

const Terry = 'Terry';

console.log(jonas instanceof Person);
console.log(Terry instanceof Person);