Prototype_Inheritance.js

/*
	constructor for Robot
*/
var Robot = function(name) {
	this.name = name;
};

/*
	property in prototye
*/
Robot.prototype.name = null;

/*
	redefine toString
*/
Robot.prototype.toString = function() {
	return '[Robot named '+this.name+']';
};

Robot.prototype.shutDown = function() {
	console.log(this.name + ' is shutting down…');
};

Robot.prototype.say = function(something) {
	console.log("In a robot voice, "+this.name+" says:\n"+something);
};


/*
	constructor for new object
*/
var Robocop = function(name) {
	this.name = name;
};

/*
	inherit the prototype of Robot
*/
Robocop.prototype = new Robot();

/*
	redefine toString
*/
Robocop.prototype.toString = function() {
	return '[Robocop named '+this.name+']';
};

/*
	add a new method
*/
Robocop.prototype.arrest = function() {
	this.say('Come with me or there will be… trouble');
};

/*
	this redefines shutDown and calls the "parent" version as well
*/
Robocop.prototype.shutDown = function() {
	this.say(this.name+' requires sleep!');
	Robot.prototype.shutDown.call(this);
};


/*
	Make a couple functions to check instanceof
*/
function is_robot(obj) {
	if (obj instanceof Robot) {
		console.log(obj.name + ' is a Robot');
	} else {
		console.log(obj.name + ' is NOT a Robot');
	}
}

function is_robocop(obj) {
	if (obj instanceof Robocop) {
		console.log(obj.name + ' is a Robocop');
	} else {
		console.log(obj.name + ' is NOT a Robocop');
	}
}


/*
	now make a couple object instances
*/
var robby = new Robot('Robby');
console.log(robby.toString());
robby.shutDown();
is_robot(robby);
is_robocop(robby);

var murphy = new Robocop('Murphy');
console.log(murphy.toString());
murphy.arrest();
is_robot(murphy);
is_robocop(murphy);

/*
	add a new function to the base prototype
*/
Robot.prototype.shockAttack = function() {
	console.log(this.name + " zaps you!");
}

/*
	use the new function in an inheriting object
*/
murphy.shockAttack();
murphy.shutDown();