Jun 5, 2024 · In JavaScript, both undefined and null represent the absence of a meaningful value, but they have different purposes and are used in distinct contexts. Knowing when and how to use each can help you write clearer, more predictable code.

May 10, 2013 · There are two features of null we should understand: null is an empty or non-existent value. null must be assigned. You can assign null to a variable to denote that currently that variable does not have any value but it will have later on. A null means absence of a value. example:- let a = null; console.log(a); //null

Jan 4, 2024 · To check for null SPECIFICALLY you would use this: if (variable === null) This test will ONLY pass for null and will not pass for "", undefined, false, 0, or NaN. Additionally, I've provided absolute checks for each "false-like" value (one that would return true for !variable).

Nowadays most browsers support the Nullish coalescing operator (??) and the Logical nullish assignment (??=), which allows a more concise way to assign a default value if a variable is null or undefined, for example:

Mar 13, 2025 · The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.

JavaScript uses the null value to represent the intentional absence of any object value. If you find a variable or a function that returns null, it means that the expected object couldn’t be created. The following example defines the Circle class whose constructor accepts an argument radius.

In this tutorial, you will learn about null and undefined data types available in JavaScript with the help of examples.

Jun 2, 2023 · In JavaScript, the null keyword is a primitive value that represents the intentional absence of any object value. It is often used to indicate that a variable does not currently have a value or does not refer to any object. Here’s how the null keyword works in JavaScript:

Sep 21, 2020 · In this post, you'll learn everything about null in JavaScript: its meaning, how to detect it, the difference between null and undefined, and why using null extensively creates code maintenance difficulties.

Feb 18, 2025 · Both null and undefined are considered falsy values in JavaScript, meaning they evaluate to false in conditional expressions. Null is often intentional, indicating a deliberate absence of a value. Undefined is often unintentional, indicating a variable has been declared but not yet assigned a value.