• Number
  
• String
  
• Boolean
  
• Null     //   typeof null === 'object'
  
• Undefined
  
• Object
  

• Using Object Literals

• Using Constructor with new keyword

• Using Object.create
  

function myFunction(prop) { 
	return something ;
};
var myFunction = function (prop) { };
var myFunction = function newFn(prop) { }; 

• The arguments object is a local variable available within all functions
  
• Can access and set values by treating it as an Array
  

function Phone( model , manufacturer) { 
    this.model = model ;
    this.manufacturer = manufacturer ;
    this.displayModel = function(){
        alert(this.model);
    }
    this.displayManu = function(){
        alert(this.manufacturer);
    }
};

var myXperia = new Phone('Xperia','SONY'); 

• Declaring private methods and variables using var.
  

function Phone( ) { 
    var propertyName = 'some value';
    var functionName = function(){ ... };
}; 

• Declaring public methods and variables using this  this.propertyName = 'some value';
  

• Declaring static variables and methods.
  

• Way of caching a result using static properties
  

function isPrime( num ) { 
  if ( isPrime.cache[ num ] != null ) 
    return isPrime.cache[ num ]; 
   
  var prime = num != 1; // Everything but 1 can be prime 
  for ( var i = 2; i < num; i++ ) { 
    if ( num % i == 0 ) { 
      prime = false; 
      break; 
    } 
  } 
  isPrime.cache[ num ] = prime ;
  return prime; 
} 
isPrime.cache = {};
isPrime(5);
 

• Context :
  
• We can use apply() and call() methods to change the context of another object
  

• Function.prototype.call()
  

• Function.prototype.apply()
  

• Example :
  

• Changing Context :
  

function Car(){
    this.noWheels = 4; 
}
Car.prototype.color = 'black';
var c = new Car();
function changeColor(color){
    this.color = color;
}
changeColor.call(c,'white');
alert(c.color); 

• We can add properties and methods using prototype
  
• Saves memory
  

function Car(){
}
Car.prototype.wheels = 4;

Car.prototype.drive = function (){
    alert('drive');
};
 

function Car(){
    this.noWheels = 4; 
}
Car.prototype.color = 'black';
   var c = new Car();

  c.hasOwnProperty('color');  // false
  c.hasOwnProperty('noWheels');  // true
  c.__proto__.hasOwnProperty('color') // true
 

function Person(){}
Person.prototype.dance = function( ){ alert('dancer');  };

function Dancer(){}
Dancer.prototype = new Person();

var dancer = new Dancer();
dancer.dance();
alert(dancer instanceof Dancer); // true
alert(dancer instanceof Person); // true 

• Some Piece is missing
  

alert(dancer.constructor === Dancer) // false
alert(dancer.constructor === Person) // true
 

• We have to reset the Constructor
  

function Product(name, price) {
  this.name = name;
  this.price = price;

  if (price < 0)
    throw RangeError('Cannot create product "' + name + '" with a negative price');
  return this;
} 

function Food(name, price) {
  Product.call(this, name, price); // call super using call and passing ‘this’ 
  this.category = 'food';
}
Food.prototype = new Product();
var cheese = new Food('feta', 5);
alert(cheese.name); 

function MyError(message) {
  this.name = "MyError";
  this.message = message || "Default Message";
}
MyError.prototype = new Error();
MyError.prototype.constructor = MyError; 

• However Mozilla says Custom Error Messages will not give the error line correctly
  

function Person(){}
Person.prototype.dance = function( ){ alert('dance');  };

function Dancer(){}
Dancer.prototype = new Person();
Dancer.prototype.dance = function(){ alert('dance better')};
var dancer = new Dancer();
dancer.dance(); // alert dance better