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Prototype and Prototypal Inheritance in JavaScript

Prototype and Prototypal Inheritance in JavaScript

Prototype is a core concept in JavaScript which helps us to reuse code in our program.

saiprasad padhy's photo
saiprasad padhy
ยทJan 9, 2023ยท

2 min read

Table of contents

  • Prototype
  • Prototype chain
  • Prototypal Inheritance

Prototype is a core concept in JavaScript which helps us to reuse code in our program. In this blog, I will explain what is a prototype, the prototype chain and how prototypal inheritance works.

Prototype

Let's understand this topic by simple code.

In the above code, I have created an empty object obj and inserted name and age properties to it.

Let's see by accessing those properties.

If you observe the above code, We only added two properties to our object obj but we are able to call toString() function which we didn't initialise. Similarly when we try to call anything(), We got an error.

Now, Let's try with an array.

Now, along with array items, We are seeing all the array methods in a special object called prototype

This mechanism of inheriting features from another object is called a prototype.

Prototype chain

We can access the prototype object by calling __proto__ Let's see what we have in the prototype of the object we created earlier.

Let's see what we have in the prototype of the array.

If we observe carefully, We have prototype of the array and prototype of the object as its prototype and both are the same. We can prove it by the below code.

This chaining of the prototypes is known as the Prototype chain. Also, from this, we can say that everything in JavaScript is some sort of Object.

Prototypal Inheritance

Prototypal Inheritance is very different from Inheritance in other languages. Let's understand this concept by an example.

Here, We have created an object human which has a function talk() and we have created another object superman (Object.create() is just another way of creating objects.)by inheriting human.

Now, We can call talk() from superman as well because it is inheriting the human object. Let's prove it.

In the above code, I have created another method inside superman. Now We can access both fly() and talk() from the superman object.

And, If we observe carefully, the inherited methods are not directly under the superman object. those are added to the prototype of superman object. This type of inheritance is called Prototypal Inheritance.


I hope you learnt something new by reading this post. Please like this and share this post with your friends and community, it motivates me to write more awesome blog posts.

Will see you in my next blog post ๐Ÿ˜Š

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