JavaScript Prototypal Inheritance

JS-Inheritance.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 = {
		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;
		}
};


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

Employee.prototype = {
	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 = {
	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();
var narendra  = new Employee("Narendra", 30, "Engineer");
narendra.eat().drive().office();
var chetan = new Manager("Chetan", 24, "Doctor", "Research");
chetan.eat().drive().office().presentation();