The 3 ways to declare objects in javascript

declaring_objects_in_Javascript.js

/*
* 1. USING A FUNCTION
* notes: this is not the best solution for
* 	large applications, because your constructor
* 	functions are global objects and could accidentally
* 	be overwritten.
*/

// create a Class Apple 
function Apple(type){

	this.type = type; 
	this.color = 'red'; 
	this.getInfo = getAppleInfo; 

}

// constructor function for the Apple Class
function getAppleInfo (){
	return this.color + ' ' + this.type + ' ' + 'apple';
}

// object instance of Apple Class
var apple = new Apple('macintosh');
apple.color = 'reddish';
console.log(apple.getInfo());
console.log(apple);



/*
* 1.1 METHODS DEFINED INTERNALLY
* notes: using this solution prevents global
* 	overwrites without changing the way you
* 	instantiate an object of Class Apple.
* 	But method getInfo is recreated with each instance.
*/
function Apple(type){

	this.type = type;
	this.color = 'red';
	this.getInfo = function(){
		return this.color + ' ' + this.type + ' ' + 'apple';
	};

}

// object instance of Apple Class
var apple = new Apple('macintosh');
apple.color = 'reddish';
console.log(apple.getInfo());
console.log(apple);



/*
* 1.2 METHODS ADDED TO THE PROTOTYPE
* notes: A more inexpensive way of adding
* 	to the prototype of the constructor function
* 	if you don't want the constructor to be
* 	recreated with each instance.
*/
function Apple(type){

	this.type = type;
	this.color = 'red';

}

Apple.prototype.getInfo = function(){
	return this.color + ' ' + this.type + ' ' + 'apple';
};

// object instance of Apple Class
var apple = new Apple('macintosh');
apple.color = 'reddish';
console.log(apple.getInfo());
console.log(apple);





/*
* 2. USING OBJECT LITERALS
* example of literal notation:  var o = {};
* example of regular notation:  var o = new Object();

* notes: in this case you don't need to (and cannot) create an
* 	instance of the class, it already exists. So you simply
* 	start using this instance. Such an object is sometimes
* 	called a singleton.
*/


var apple = {
	type: 'macintosh',
	color: 'red',
	getInfo: function () {
		return this.color + ' ' + this.type + ' ' + 'apple';
	}
}

apple.color: 'reddish';
console.log (apple.getInfo());



/*
* 3. SINGLETON USING A FUNCTION
* notes: the "= new function(){}" does two 
* 	things at the same time: define a 
* 	function (an anonymous constructor function) 
* 	and invoke it with new. 
*/

var apple = new function(){
	this.type = 'macintosh';
	this.color = 'red';
	this.getInfo = function(){
		return this.color + ' ' this.type + ' ' + 'apple';
	}
}

apple.color = 'reddish';
console.log (apple.getInfo());