How to Check if a Variable is Null or Empty in JavaScript

In JavaScript, or any other language, when you create a variable, you assign it some values. However, in the other case, it acts like an undefined variable. If a variable holds an empty string, it means the variable is “empty” due to its zero length. In order to indicate the absence of any object value, you can also give a variable the value “null“.

This blog will discuss the methods for determining whether a variable is null or empty.

How to Check if a Variable is Null or Empty in JavaScript?

For verifying whether the variable is null or empty, you can use the following methods:

• length property
• strict equality (===) with OR (||) operator

Let’s go through the working of these methods individually.

Method 1: Check if a Variable is Null or Empty Using length Property

To verify whether a variable is null or empty, you can use the “length” property, which is the fundamental property of JavaScript. It is possible to perform self-reflection in JavaScript functions that interact with other functions by using the length property

Syntax
Follow the below-given syntax for the length property:

Here, we will check if the length of the variable “val” is zero or not.

Example
In this example, we will create an empty string stored in a variable “val”:

Then, we will use the length property in a conditional statement to check if the length of the variable is 0, representing that it is an empty string:

Execute the above code and see the output:

Let’s move to the next method!

Method 2: Check if a Variable is Null or Empty Using strict equality (===) and OR (||) Operator

Another method to verify the variable is null or empty is using the strict equality “===” operator with OR “||” operator. The strict equality operator checks the two operands of different types and returns a boolean value true if they are the same.

Syntax
You can use the following syntax for checking the variable is null or empty:

Example
Here, we will create a variable “val” and assigned a “null” value to it:

Then, we will use the OR operator with strict equality operator in the “if” conditional statement to verify whether the variable is null or empty:

The output indicates that the variable “val” is null:

We have presented all the methods to check if a variable is null or empty in JavaScript.

Conclusion

For verifying whether the variable is null or empty, you can use the length property of the JavaScript or the strict equality (===) operator with the OR (||) operator in JavaScript. The length property is mainly used for the empty variables because the empty variables contain 0 lengths while null shows the absence of object value. In this blog, we have discussed the methods for checking the variable, whether it is null or empty or not.