pllearns/1. Getters and Setters

## 1. Getters and Setters
Here is an efficient way to get getters and setters:

<!DOCTYPE HTML>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Javascript Practice</title>
</head>
<body>
<script type="text/javascript">
//getters and setters //

var Circle = function(radius) {
  this._radius = radius;
}

Circle.prototype = {
  set radius(radius) {this._radius = radius;},
  get radius() {return this._radius;},
  get area() {return Math.PI * (this._radius * this._radius);}
};

var circ = new Circle(10);

circ.radius = 15;

document.write("A circle with radius " + circ.radius + " has an area of " + circ.area.toFixed(2) + "<br />")

</script>
</body>
</html>

## 2. Example of prototype and object polymorphism
<!DOCTYPE HTML>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Javascript Practice</title>
</head>
<body>
<script type="text/javascript">

function Animal() {
  this.name = "Animal";

  this.toString = function() {
    return "My name is " + this.name;
  };
}

function Canine() {
  this.name = "Canine";
}

function Wolf() {
  this.name = "Wolf";
}

Canine.prototype = new Animal();
Wolf.prototype = new Canine();

Canine.prototype.constructor = Canine;
Wolf.prototype.constructor = Wolf;

var arcticWolf = new Wolf();

document.write(arcticWolf.toString() + "<br />")

</script>
</body>
</html>

## 3. Prototypal Inheritance Example
<script type="text/javascript">

function Animal() {
  this.name = "Animal";

  this.toString = function() {
    return "My name is " + this.name;
  };
}

function Canine() {
  this.name = "Canine";
}

function Wolf() {
  this.name = "Wolf";
}

Canine.prototype = new Animal();
Wolf.prototype = new Canine();

Canine.prototype.constructor = Canine;
Wolf.prototype.constructor = Wolf;

var arcticWolf = new Wolf();

document.write(arcticWolf.toString() + "<br />")

document.write("is wolf instance of " + (arcticWolf instanceof Animal) + "<br />")

Animal.prototype.sound = "Grrrr"
Animal.prototype.getSound = function() {
  return this.name + " says " + this.sound;
}

Canine.prototype.sound = "Woof"
Wolf.prototype.sound = "Grrrr Woof"

document.write(arcticWolf.getSound() + "<br />");

function Rodent() {
  this.name = "Rodent";
}

function Rat() {
  this.name = "Rat";
}

Rodent.prototype = new Animal();

Rat.prototype = Rodent.prototype;

Rodent.prototype.constructor = Rodent;
Rat.prototype.constructor = Rat;

var caneRat = new Rat();

document.write(caneRat.toString() + "<br />");

</script>

## 4. Streamlining the process of inheritance
function extend(Child, Parent){
  var Temp = function(){};

    Temp.prototype = Parent.prototype;

    Child.prototype = new Temp();

    Child.prototype.constructor = Child;
}

function Deer() {
  this.name = "Deer";
  this.sound = "Snort";
}

extend(Deer, Animal);

var elk = new Deer();

document.write(elk.getSound() + "<br />")

## 5. Super Class Example
function Vehicle(name) {
  this.name = "Vehicle";
}

Vehicle.prototype = {
  drive: function() {
    return this.name + " drives forward";
  },
  stop: function() {
    return this.name + " stops";
  }
}

function Truck(name) {
  this.name = name;
}

Truck.prototype = new Vehicle();
Truck.prototype.constructor = Truck;

Truck.prototype.drive = function() {
  var driveMsg = Vehicle.prototype.drive.apply(this);

  return driveMsg += " through a field";
}

var jeep = new Truck("Jeep");

document.write(jeep.drive() + "<br />");
document.write(jeep.stop() + "<br />");

## 6. ECMA5 and ECMA6 comparisons
//ECMA5
var addStuff = {
  sum: function(num1, num2) {
    return num1 + num2;
  }
};
document.write("1 + 2 = ", addStuff.sum(1,2) + "<br />");

//ECMA6
var addStuff = {
  sum(num1, num2){
    return num1 + num2;
  }
}
document.write("1 + 2 = ", addStuff.sum(1,2) + "<br />");

## 7. Classes in ES6 Comparison
//ECMA5
var Point = function(xPos, yPos){
  this.xPos = xPos;
  this.yPos = yPos;
};

Point.prototype.getPos = function(){
  return "X: " + this.xPos + " Y : " + this.yPos;
};

var point = new Point(100, 200);

document.write("Point Pos : " + point.getPos() + "<br />");

//ECMA6
class Point {
  constructor(xPos, yPos) {
    this.xPos = xPos;
    this.yPos = yPos;
  }

  getPos(){
    return "X: " + this.xPos + " Y : " + this.yPos;
  }
}

var point = new Point(100, 200);
document.write("Point Pos : " + point.getPos() + "<br />");

## 8. Class with super constructor in ES6
class Animal {
  constructor(name) {
    this.name = name;
  }

  toString() {
    return "Animal is name " + this.name;
  }

  static getAnimal() {
    return new Animal("No Name")
  }
}

class Dog extends Animal {
  constructor(name, owner) {
    super(name);
    this.owner = owner;
  }

  toString() {
    return super.toString() + "<br />Dog is named " + this.name;
  }
}

var rover = new Dog("Rover", "Paul");

document.write(rover.name + " is owned by " + rover.owner + "<br />");

document.write(rover.toString() + "<br />");

var bowser = Animal.getAnimal();

document.write(" Bowser info : " + bowser.toString() + "<br />");

## 9. Singleton Pattern
<!DOCTYPE HTML>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Javascript Practice</title>
</head>
<body>
<script type="text/javascript">

function Hero(name) {
  if(typeof Hero.instance === 'object') {
    return Hero.instance;
  }

  this.name = name;
  Hero.instance = this;
  return this;
}

var phillipHero = Hero("Phil");
document.write("Our hero is " + phillipHero.name + "<br />");

var sallyHero = Hero("Sally");
document.write("Our hero is " + sallyHero.name + "<br />");

</script>
</body>
</html>

## 9a. Factory Pattern
function Sword(desc){
  this.weaponType = "Sword";
  this.metal = desc.metal || "Steel";
  this.style = desc.style || "Longsword";
  this.hasMagic = desc.hasMagic || false;
}

function Bow(desc){
  this.weaponType = "Bow";
  this.material = desc.metal || "Wood";
  this.style = desc.style || "Longbow";
  this.hasMagic = desc.hasMagic || false;
}

function WeaponFactory(){};

WeaponFactory.prototype.makeWeapon = function(desc) {
  var weaponClass = null;

  if(desc.weaponType === "Sword"){
    weaponClass = Sword;
  } else if (desc.weaponType === "Bow"){
    weaponClass = Bow;
  } else {
    return false;
  }

  return new weaponClass(desc);
}

var myWeaponFactory = new WeaponFactory();

var bladeFist = myWeaponFactory.makeWeapon({
  weaponType: "Sword",
  metal: "Dark Iron",
  style: "Scythe",
  hasMagic: true
});

document.write(bladeFist.weaponType + " of type " + bladeFist.style + " crafted from " + bladeFist.metal + "<br />");

## 9b. Decorator Pattern
function Pizza(price) {
  this.price = price || 10;
}

Pizza.prototype.getPrice = function() {
  return this.price
}

function ExtraCheese(pizza) {
  var prevPrice = pizza.price;

  pizza.price = prevPrice + 1;
}

var myPizza = new Pizza(10);

ExtraCheese(myPizza);

document.write("Cost of Pizza : $" + myPizza.price + "<br />");

## 9c. Observable Pattern
var Observable = function() {
  this.subscribers = [];
}

Observable.prototype = {
  subscribe: function(subscriber){
    this.subscribers.push(subscriber);
  },

  unsubscribe: function(unsubscriber) {
    for(i = 0; i < this.subscribers.length; i++) {
      if(this.subscribers[i] === unsubscriber) {
        this.subscribers.splice(i, 1);

        return unsubscriber.name;
      }
    }
  },

  publish: function(data) {
    for(i = 0; i < this.subscribers.length; i++) {
      this.subscribers[i].receiveData(data);
    }
  }
};

var MorganFanny = {
  name: "Morgan Fanny",
  receiveData: function(data) {
    document.write(this.name +  " received your info " + data + "<br />");
  }
}

var BoldmanYaks = {
  name: "Boldman Yaks",
  receiveData: function(data) {
    document.write(this.name +  " received your info " + data + "<br />");
  }
}

observable = new Observable();

observable.subscribe(MorganFanny);
observable.subscribe(BoldmanYaks);

observable.publish('IBM at $145.30');

document.write(observable.unsubscribe(MorganFanny) + " unsubscribed<br />");

observable.publish('IBM at $144.30');
	Here is an efficient way to get getters and setters:

	<!DOCTYPE HTML>
	<html lang="en">
	<head>
	<meta charset="utf-8">
	<title>Javascript Practice</title>
	</head>
	<body>
	<script type="text/javascript">
	//getters and setters //

	var Circle = function(radius) {
	this._radius = radius;
	}

	Circle.prototype = {
	set radius(radius) {this._radius = radius;},
	get radius() {return this._radius;},
	get area() {return Math.PI * (this._radius * this._radius);}
	};

	var circ = new Circle(10);

	circ.radius = 15;

	document.write("A circle with radius " + circ.radius + " has an area of " + circ.area.toFixed(2) + "<br />")

	</script>
	</body>
	</html>
	<script type="text/javascript">

	function Animal() {
	this.name = "Animal";

	this.toString = function() {
	return "My name is " + this.name;
	};
	}

	function Canine() {
	this.name = "Canine";
	}

	function Wolf() {
	this.name = "Wolf";
	}

	Canine.prototype = new Animal();
	Wolf.prototype = new Canine();

	Canine.prototype.constructor = Canine;
	Wolf.prototype.constructor = Wolf;

	var arcticWolf = new Wolf();

	document.write(arcticWolf.toString() + "<br />")

	document.write("is wolf instance of " + (arcticWolf instanceof Animal) + "<br />")

	Animal.prototype.sound = "Grrrr"
	Animal.prototype.getSound = function() {
	return this.name + " says " + this.sound;
	}

	Canine.prototype.sound = "Woof"
	Wolf.prototype.sound = "Grrrr Woof"

	document.write(arcticWolf.getSound() + "<br />");

	function Rodent() {
	this.name = "Rodent";
	}

	function Rat() {
	this.name = "Rat";
	}

	Rodent.prototype = new Animal();

	Rat.prototype = Rodent.prototype;

	Rodent.prototype.constructor = Rodent;
	Rat.prototype.constructor = Rat;

	var caneRat = new Rat();

	document.write(caneRat.toString() + "<br />");

	</script>
	function extend(Child, Parent){
	var Temp = function(){};

	Temp.prototype = Parent.prototype;

	Child.prototype = new Temp();

	Child.prototype.constructor = Child;
	}

	function Deer() {
	this.name = "Deer";
	this.sound = "Snort";
	}

	extend(Deer, Animal);

	var elk = new Deer();

	document.write(elk.getSound() + "<br />")
	function Vehicle(name) {
	this.name = "Vehicle";
	}

	Vehicle.prototype = {
	drive: function() {
	return this.name + " drives forward";
	},
	stop: function() {
	return this.name + " stops";
	}
	}

	function Truck(name) {
	this.name = name;
	}

	Truck.prototype = new Vehicle();
	Truck.prototype.constructor = Truck;

	Truck.prototype.drive = function() {
	var driveMsg = Vehicle.prototype.drive.apply(this);

	return driveMsg += " through a field";
	}

	var jeep = new Truck("Jeep");

	document.write(jeep.drive() + "<br />");
	document.write(jeep.stop() + "<br />");
	//ECMA5
	var addStuff = {
	sum: function(num1, num2) {
	return num1 + num2;
	}
	};
	document.write("1 + 2 = ", addStuff.sum(1,2) + "<br />");

	//ECMA6
	var addStuff = {
	sum(num1, num2){
	return num1 + num2;
	}
	}
	document.write("1 + 2 = ", addStuff.sum(1,2) + "<br />");
	//ECMA5
	var Point = function(xPos, yPos){
	this.xPos = xPos;
	this.yPos = yPos;
	};

	Point.prototype.getPos = function(){
	return "X: " + this.xPos + " Y : " + this.yPos;
	};

	var point = new Point(100, 200);

	document.write("Point Pos : " + point.getPos() + "<br />");

	//ECMA6
	class Point {
	constructor(xPos, yPos) {
	this.xPos = xPos;
	this.yPos = yPos;
	}

	getPos(){
	return "X: " + this.xPos + " Y : " + this.yPos;
	}
	}

	var point = new Point(100, 200);
	document.write("Point Pos : " + point.getPos() + "<br />");
	class Animal {
	constructor(name) {
	this.name = name;
	}

	toString() {
	return "Animal is name " + this.name;
	}

	static getAnimal() {
	return new Animal("No Name")
	}
	}

	class Dog extends Animal {
	constructor(name, owner) {
	super(name);
	this.owner = owner;
	}

	toString() {
	return super.toString() + "<br />Dog is named " + this.name;
	}
	}

	var rover = new Dog("Rover", "Paul");

	document.write(rover.name + " is owned by " + rover.owner + "<br />");

	document.write(rover.toString() + "<br />");

	var bowser = Animal.getAnimal();

	document.write(" Bowser info : " + bowser.toString() + "<br />");
	function Sword(desc){
	this.weaponType = "Sword";
	this.metal = desc.metal \|\| "Steel";
	this.style = desc.style \|\| "Longsword";
	this.hasMagic = desc.hasMagic \|\| false;
	}

	function Bow(desc){
	this.weaponType = "Bow";
	this.material = desc.metal \|\| "Wood";
	this.style = desc.style \|\| "Longbow";
	this.hasMagic = desc.hasMagic \|\| false;
	}

	function WeaponFactory(){};

	WeaponFactory.prototype.makeWeapon = function(desc) {
	var weaponClass = null;

	if(desc.weaponType === "Sword"){
	weaponClass = Sword;
	} else if (desc.weaponType === "Bow"){
	weaponClass = Bow;
	} else {
	return false;
	}

	return new weaponClass(desc);
	}

	var myWeaponFactory = new WeaponFactory();

	var bladeFist = myWeaponFactory.makeWeapon({
	weaponType: "Sword",
	metal: "Dark Iron",
	style: "Scythe",
	hasMagic: true
	});

	document.write(bladeFist.weaponType + " of type " + bladeFist.style + " crafted from " + bladeFist.metal + "<br />");
	function Pizza(price) {
	this.price = price \|\| 10;
	}

	Pizza.prototype.getPrice = function() {
	return this.price
	}

	function ExtraCheese(pizza) {
	var prevPrice = pizza.price;

	pizza.price = prevPrice + 1;
	}

	var myPizza = new Pizza(10);

	ExtraCheese(myPizza);

	document.write("Cost of Pizza : $" + myPizza.price + "<br />");
	var Observable = function() {
	this.subscribers = [];
	}

	Observable.prototype = {
	subscribe: function(subscriber){
	this.subscribers.push(subscriber);
	},

	unsubscribe: function(unsubscriber) {
	for(i = 0; i < this.subscribers.length; i++) {
	if(this.subscribers[i] === unsubscriber) {
	this.subscribers.splice(i, 1);

	return unsubscriber.name;
	}
	}
	},

	publish: function(data) {
	for(i = 0; i < this.subscribers.length; i++) {
	this.subscribers[i].receiveData(data);
	}
	}
	};

	var MorganFanny = {
	name: "Morgan Fanny",
	receiveData: function(data) {
	document.write(this.name + " received your info " + data + "<br />");
	}
	}

	var BoldmanYaks = {
	name: "Boldman Yaks",
	receiveData: function(data) {
	document.write(this.name + " received your info " + data + "<br />");
	}
	}

	observable = new Observable();

	observable.subscribe(MorganFanny);
	observable.subscribe(BoldmanYaks);

	observable.publish('IBM at $145.30');

	document.write(observable.unsubscribe(MorganFanny) + " unsubscribed<br />");

	observable.publish('IBM at $144.30');