classes

classes.js

// Before ES6
function Person(name, age) {
  this.name = name;
  this.age = age;
}

// a greeter method on a Person object
Person.prototype.greet = function() {
  console.log('Hi, I am ' + this.name);
}

// a "class method" on the Person "class"
Person.older = function(person1, person2) {
  return (person1.age >= person2.age) ? person1 : person2
}

// With ES6
class Person {
  constructor (name, age) {
    this.name = name;
    this.age = age;
  }

  greet() {
    console.log('Hi, I am ' + this.name);
  }

  /*
    note the static keyword makes the method into
    a class method, so it's meant to be invoked on
    the class, not an instance of the class.
  */
  static order (person1, person2) {
    return (person1.age >= person2.age) ? person1 : person2
  }
}

// class inheritance
class AngryPerson extends Person {
  constructor (name, age, favorite_expletive) {
    super(name, age);
    this.favorite_expletive = favorite_expletive;
  }

  yell() {
    console.log(this.favorite_expletive + '!');
  }
}