JavaScript Tutorial - Polymorphism in JavaScript

Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2015/02/polymorphism-in-javascript.html Healthy diet is very important both for the body and mind. If you like Aarvi Kitchen recipes, please support by sharing, subscribing and liking our YouTube channel. Hope you can help. https://www.youtube.com/channel/UC7sEwIXM_YfAMyonQCrGfWA/?sub_confirmation=1 In this video we will discuss, how to implement polymorphism in JavaScript with an example. Object oriented programming languages like C# and Java, support polymorphism. Here is a C# example. public partial class WebForm1 : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Shape[] shapes = new Shape[] { new Shape(), new Circle(), new Square(), new Triangle() }; foreach (Shape shape in shapes) { Response.Write(shape.draw() + "[br/]"); } } } public class Shape { public virtual string draw() { return "I am a generic shape"; } } public class Circle : Shape { public override string draw() { return "I am a circle"; } } public class Square : Shape { public override string draw() { return "I am a square"; } } public class Triangle : Shape {} Output : I am a generic shape I am a circle I am a square I am a generic shape Since JavaScript is also an object oriented programming language, it also supports the concept of polymorphism. Here is an example. [script type="text/javascript"] // Shape object is be the base object var Shape = function () { } // Add draw function to the Shape prototype // Objects derived from Shape should be able to override draw() method Shape.prototype.draw = function () { return "I am a generic shape"; } // Create a Circle object var Circle = function () { } // Make shape the parent for Circle Circle.prototype = Object.create(Shape.prototype); // Circle object overrides draw() method Circle.prototype.draw = function () { return "I am a circle"; } var Square = function () { } Square.prototype = Object.create(Shape.prototype); Square.prototype.draw = function () { return "I am a square"; } var Triangle = function () { } Triangle.prototype = Object.create(Shape.prototype); var shapes = [new Shape(), new Circle(), new Square(), new Triangle()]; shapes.forEach(function (val) { document.write(val.draw() + "[br/]") }); [/script] Ouptut: I am a generic shape I am a circle I am a square I am a generic shape