Null vs Undefined in JavaScript

In this tutorial, you will learn about JavaScript Null vs Undefined.

Null and undefined represent empty or missing values.

Many Developers get confused between these two, so I will clear each.

What is null in JavaScript?

null is an intentional empty value. If you declare a variable and define the value null in it.

let name = null;
console.log(name); // null

Note: If you declare a null value, that means it does not have any value.

What is undefined in JavaScript?

undefined means a variable has been declared but not assigned any value.

let name;
console.log(name); // undefined

Difference between Null vs Undefined

You can clear the difference through below details.

Type Checking

Now, you will check Type Checking through below code.

1. typeof null returns Object.

2. typeof undefined returns undefined.

typeof null;      // "object"
typeof undefined; // "undefined"

Comparison of null vs undefined

null == undefined   // true
null === undefined  // false

Note:

== is used to check only value.

=== is used to check value and type.