JavaScript Prototypal Inheritance with Private function and Private-Static properties

JS-Inheritance-5.js

/*		Author : Narendra Sisodiya
*		Date : Thu Jul 19 18:16:38 IST 2012
* 		Licence : Public Code
*		Purpose : Inheritance
*		Multilevel JavaScript Prototypal Inheritance
*/

function inherit(Child){
	return {
		"from": function(Parent){
			
			var old_prototype = Child.prototype;
			
			/*var F = function(){};
			F.prototype = Parent.prototype;
			Child.prototype = new F();*/
			
			Child.prototype = Object.create(Parent.prototype);
			
			Child.prototype.constructor = Child;
			for (i in old_prototype) {
				Child.prototype[i] = old_prototype[i];
			}
			
			Child.parent = Parent;
		}
	}
}


var Person = function(full_name, age) {
	this.full_name = full_name;
	this.age = age;
}

Person.prototype = (function(){

	//Private Function
	var talkToWife = function(){
		console.log("I love you");
	};
	
	//Private-Static properties
	//		All objects has access to this property via public functions
	var x ;
	
	//Public Function
	return {
			drive: function() {
				if(this.age >= 18){
					console.log(this.full_name + " is driving");
				}else{
					console.log(this.full_name + " is not eligible for driving");
				}
			
				return this;
			},
			eat: function(){
				console.log(this.full_name + " is eating");
				return this;
			},
			talk: function(){
				talkToWife();
				return this;
			},
			setx: function(_x){
				x = _x;
				return this;
			},
			getx: function(){
				console.log("x is " + x);
				return this;
			},
			
			
	};
})();





var Employee = function(full_name, age, job_title){
	Employee.parent.call(this,full_name, age);
	this.job_title = job_title;
};

Employee.prototype = (function(){
	var x = 2;
	return {
		office: function(){
			console.log(this.full_name + " is a "+ this.job_title + " and he is going to Office");
			return this;
		}
	};
})();


inherit(Employee).from(Person);


var Manager = function(full_name, age, job_title, dept){
	Manager.parent.call(this, full_name, age, job_title);
	this.dept = dept;
};

Manager.prototype = (function(){
	return {
		presentation: function(){
			console.log(this.full_name + " is a Manager of " + this.dept + " Department and he is doing presentiation");
			return this;
		}
	};
})();

inherit(Manager).from(Employee);

var deepak  = new Person("Deepak", 17);
deepak.eat().drive().talk().getx().setx(30).getx();
var suresh  = new Person("suresh", 17);
suresh.eat().drive().talk().getx().setx(100).getx();
deepak.getx();
var narendra  = new Employee("Narendra", 30, "Engineer");
narendra.eat().drive().office();
narendra.getx();
var chetan = new Manager("Chetan", 24, "Doctor", "Research");
chetan.eat().drive().office().presentation();