What is the role of .prototype in JavaScript?

Other Questions JavaScript
1

I have some experience with JavaScript, but I find the concept of prototype-based programming a bit confusing. Can someone explain how it operates?

var instance = new Object();
instance.prototype.display = function() { alert('Hi there!'); };
var instance2 = new instance();
instance2.display();

In previous discussions, I recall that unlike traditional object-oriented languages, JavaScript doesn't have a class structure, just objects and their instances. Is that correct?

Furthermore, what is the specific function of the '.prototype' property in JavaScript? How does it help in creating new object instances?

Correction: proper usage

var instance = new Object(); // not a proper functional object
instance.prototype.display = function() { alert('Hi there!'); }; // this is incorrect!

function MyClass() {} // a proper functional object

MyClass.prototype.display = function() { alert(‘Success’); } // this is correct

Additionally, I've found these slides quite informative.

2

Hey Harry47,

You're right about JavaScript using prototype-based programming instead of class-based structures. The .prototype property is essential for inheritance in JavaScript. It allows you to define properties and methods that should be shared among instances of a constructor function.

In your corrected example:

function MyClass() {}
MyClass.prototype.display = function() { alert('Success'); }

MyClass.prototype.display makes the display function accessible to all instances created from MyClass. When you create an instance with new MyClass(), it inherits methods from MyClass.prototype.

Hope this clears things up!