prototype & inheritance in javascript

Prototype & Inheritancein

JavaScript

C# Corner – 21st September Sunny Kumar

Prototypes in JavaScript• What is Prototype?• Augmenting the Prototype• Overwriting the Prototype• Use of Prototype• Prototype Chain

Inheritance in JavaScript• Various ways of Inheritance in JavaScript.

- are objects.- returns Value.- can return objects, including other functions.- they have properties.- they have methods.- can be copied, deleted, augmented.- special feature: Invokable.- when invoked with new keyword, returns an object named this , can be modified before it’s returned.

FunctionsSneak Peek into past…

var Person = function(name) { this.name = name; this.getName = function() { return this.name; };};var me = new Person(“Sunny");me.getName(); // “Sunny"

Constructor Functions

Sneak Peek into past…

FireBug Console …as a Learning Tool.

Prototype

Prototype

• prototype is a property of function

object.

• Only function Objects can have prototype property.

Prototype

var foo = function(){}; console.log(foo.prototype);

Object {} //output

Augmenting Prototype(Adding properties to prototype object)

Var foo=function(){};Var myFoo = new foo(); //instantiates an object of foo.foo.prototype.MaxValue=100; foo.prototype.SayHello=function(name){

return “Hi “+name+” !”;

}myFoo.SayHello(“Kumar”); // “Hi Kumar !”

Overwriting Prototype

foo.prototype={x:1,y:2}

Prototype Usage

var Person = function(name) { this.name = name; }; Person.prototype.say = function(){ return this.name; };

Prototype Usage

var dude = new Person('dude');

dude.name; // "dude“

dude.say(); // "dude“ same result

Thank You!