JavaScript: Validate whether a given value type is NaN or not

Last update on March 06 2025 11:07:04 (UTC/GMT +8 hours)

JavaScript validation: Exercise-3 with Solution

Validate NaN

Write a JavaScript function to validate whether a given value type is NaN or not.

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to validate whether a given value type is NaN or not</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function is_nan(val)
        {
        return val !== val;
       }

console.log(is_nan(NaN));

console.log(is_nan('bar'));

Sample Output:

true
false

Flowchart:

Live Demo:

See the Pen javascript-validation-exercise-3 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

Write a JavaScript function that checks if a given value is NaN by using the built-in isNaN() function and Object.is().
Write a JavaScript function that distinguishes between NaN and other falsy values, returning a specific message for NaN.
Write a JavaScript function that filters an array to return only the values that are NaN.
Write a JavaScript function that validates the input type and uses Number.isNaN() to test if it is strictly NaN.

Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript function to validate whether a given value type is error or not.
Next: Write a JavaScript function to validate whether a given value type is null or not.