JavaScript NaN Property

NaN, which stands for "Not a Number," is a special value in JavaScript that shows up when a mathematical operation can't return a valid number. This can happen if you try something like dividing zero by zero or converting a string that doesn't contain numbers.

NaN helps you spot when something went wrong with your calculations or data.

Syntax

You can assign NaN in two ways:

let a = NaN
 // OR
let a = Number.NaN

Examples of JavaScript NaN Property

Here are some examples of Javascript NaN Property :

Example 1: In this example, we are checking if the monthNumber is within the valid range (1 to 12). If it's outside this range, we assign NaN and display an appropriate message.

Output:

Month number should be between 1 and 12

Example 2: In this example, we are trying to find the square root of a negative number using Math.sqrt(). Since the square root of -1 is not a real number, it returns NaN.

Output:

NaN

Example 3: In this example, when we add NaN to a number (5 + NaN), the result is NaN, as any operation involving NaN results in NaN.

Output:

NaN

Example 4: In this example, multiplying 0 by Infinity results in NaN, as this is an indeterminate form in JavaScript.

NaN

Supported Browser

• Google Chrome
• Edge
• Firefox
• Opera
• Safari

We have a Cheat Sheet on Javascript Numbers where we covered all the important topics of Javascript to check those please go through JavaScript Number Complete Reference.