Table of contents
1.
Introduction
2.
Why This Function is Used
2.1.
Syntax, Parameter and Return Value
2.2.
Syntax:
2.3.
Parameters:
2.4.
Return Value: 
3.
Examples 
3.1.
Basic Boolean Check:
3.2.
JavaScript
3.3.
Validating Function Parameters:
3.4.
Conditional Logic Based on Data Types:
3.5.
Filtering Booleans in an Array:
3.6.
JavaScript
4.
Frequently Asked Questions
4.1.
How does _.isBoolean() differ from using the typeof operator?
4.2.
Can _.isBoolean() detect Boolean objects created with the new Boolean() constructor?
4.3.
Is _.isBoolean() necessary for simple true/false checks?
5.
Conclusion
Last Updated: Mar 27, 2024
Easy

Lodash _.isBoolean() Method

Author Rinki Deka
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Introduction

In JavaScript, accurately determining the type of a variable or expression is crucial for robust and error-free code. The Lodash library provides the _.isBoolean() method to precisely check if a given value is of the Boolean type. 

Lodash _.isBoolean() Method

This method is especially useful in scenarios involving conditional logic, validation, or configuration settings where a clear distinction between Boolean values and other data types is necessary.

Why This Function is Used

The _.isBoolean() function is used to check whether a given value is a Boolean. In JavaScript, Booleans represent a logical entity and can have two values: true or false. Identifying Boolean values accurately is important for ensuring proper execution of conditional statements, configuration checks, and data validation processes.

Syntax, Parameter and Return Value

Syntax:

_.isBoolean(value)

Parameters:

value: The value to check.

Return Value: 

(boolean) - Returns true if value is a Boolean, else false.

Examples 

Basic Boolean Check:

  • JavaScript

JavaScript

var _ = require('lodash');

console.log(_.isBoolean(false));

console.log(_.isBoolean(0));

console.log(_.isBoolean('true'));
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Output:

true
false
false


Demonstrates checking various values for Boolean type.

Validating Function Parameters:

function toggleFeature(isEnabled) {
  if (!_.isBoolean(isEnabled)) {
    throw new Error('Invalid parameter type');
  }
  // Proceed with enabling or disabling the feature
}
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Shows how to validate that a function parameter is a Boolean.

Conditional Logic Based on Data Types:

var data = { featureEnabled: true };
if (_.isBoolean(data.featureEnabled)) {
  // Handle Boolean-specific logic
}
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An example of using _.isBoolean() in conditional logic based on the data type.

Filtering Booleans in an Array:

  • JavaScript

JavaScript

var mixedArray = [true, 1, 'yes', false];

var booleans = _.filter(mixedArray, _.isBoolean);

console.log(booleans);
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 Output

[true, false]


Demonstrates filtering Boolean values from a mixed array.

Frequently Asked Questions

How does _.isBoolean() differ from using the typeof operator?

_.isBoolean() specifically checks for Boolean values (both true and false), while the typeof operator returns 'boolean' as a type. The Lodash method offers a more direct and explicit check.

Can _.isBoolean() detect Boolean objects created with the new Boolean() constructor?

Yes, _.isBoolean() can detect Boolean objects created with the new Boolean() constructor, as well as primitive Boolean values.

Is _.isBoolean() necessary for simple true/false checks?

For simple true/false checks, directly using conditional statements is often sufficient. _.isBoolean() is more useful for validating data types or filtering collections.

Conclusion

Lodash's _.isBoolean() method is a straightforward and reliable way to determine if a value is a Boolean. It is particularly useful in scenarios where the type of a value can significantly impact the logic or outcome of code execution.

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