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

Last update on March 06 2025 11:07:29 (UTC/GMT +8 hours)

JavaScript validation: Exercise-1 with Solution

Validate Boolean

Write a JavaScript function to validate whether a given value type is Boolean 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 boolean or not.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function is_boolean(value)
        {
        return value === true || value === false || toString.call(value) === '[object Boolean]';
       }

console.log(is_boolean(true));

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

Sample Output:

true
false

Flowchart:

Live Demo:

See the Pen javascript-validation-exercise-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

Write a JavaScript function that checks if a given input is strictly of type boolean using the typeof operator and returns true or false.
Write a JavaScript function that compares the input with true and false using strict equality and distinguishes boolean primitives from Boolean objects.
Write a JavaScript function that takes an array of mixed values and filters out only those that are booleans.
Write a JavaScript function that validates input and returns a custom error message if the value is not a boolean.

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