undefined vs. null

undefined vs. null


You are probably familiar with a special value in JavaScript called null. This is a value you can assign to a variable when you want to indicate that the variable has no particular value.

Well, kind-of. The fact is, null is a value, too — just like true, false, NaN, and Infinity.

Contrary to popular belief, unassigned variables (and object properties) do not begin with a default value of null. Instead, they begin with a special value called undefined.

Although it’s difficult to distinguish between undefined and null, the two values are, in fact, distinct, as demonstrated in the following scripts.

script 1

value = window . wiper;alert (“value is ” + value);

script 2

value = null;alert (“value is ” + value);

script 3

value = window . wiper;alert (value == null);

script 4

value = null;alert (value == null);

In Script 1, value equals undefined because window does not have a property named wiper. In Script 2, however, value is defined: It is defined as null. Script 3 demonstrates that when undefined is compared to null, the result is true. But null also equals null, as shown in Script 4.

So what does all this mean? Fortunately, not much: In most cases, there is little need to distinguish between null and undefined. However, if you have a habit of comparing variables to null just to see if they are defined, don’t forget that the results may be inconclusive. A true comparison means either that the variable is undefined or that the variable has been defined as null.

Share the Post:
XDR solutions

The Benefits of Using XDR Solutions

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several

data fivetran pricing

Fivetran Pricing Explained

One of the biggest trends of the 21st century is the massive surge in analytics. Analytics is the process of utilizing data to drive future decision-making. With so much of

kubernetes logging

Kubernetes Logging: What You Need to Know

Kubernetes from Google is one of the most popular open-source and free container management solutions made to make managing and deploying applications easier. It has a solid architecture that makes

ransomware cyber attack

Why Is Ransomware Such a Major Threat?

One of the most significant cyber threats faced by modern organizations is a ransomware attack. Ransomware attacks have grown in both sophistication and frequency over the past few years, forcing

data dictionary

Tools You Need to Make a Data Dictionary

Data dictionaries are crucial for organizations of all sizes that deal with large amounts of data. they are centralized repositories of all the data in organizations, including metadata such as