---
title: Javascript Booleans
description: "> A JavaScript Boolean represents one of two values: **true** or **false**. --- ## Boolean Values Very often, in programming, you will need a data type that can only have one of two values, like - YES / NO - ON / OFF…"
url: "https://apprentice.mn/docs/javascript-booleans/"
updated: "2021-05-13"
category: Javascript
---

# Javascript Booleans

> A JavaScript Boolean represents one of two values: **true** or **false**.

---

## Boolean Values

Very often, in programming, you will need a data type that can only have one of two values, like

- YES / NO
- ON / OFF
- TRUE / FALSE

For this, JavaScript has a **Boolean** data type. It can only take the values **true** or **false**.

---

## The Boolean() Function

You can use the `Boolean()` function to find out if an expression (or a variable) is true:

### Example

      `Boolean(10 > 9)        // returns true`

Or even easier:

### Example

      `(10 > 9)              // also returns true
10 > 9                // also returns true`

## Comparisons and Conditions

The chapter JS Comparisons gives a full overview of comparison operators.

The chapter JS Conditions gives a full overview of conditional statements.

Here are some examples:

| Operator | Description | Example |
| --- | --- | --- |
| == | equal to | if (day == “Monday”) |
| > | greater than | if (salary > 9000) |
| < | less than | if (age < 18) |

The Boolean value of an expression is the basis for all JavaScript comparisons and conditions.

---

                  

---

## Everything With a “Value” is True

### Examples

      `100

3.14

-15

"Hello"

"false"

7 + 1 + 3.14`

## Everything Without a “Value” is False

The Boolean value of **0** (zero) is **false**:

      `Everything Without a "Value" is False
The Boolean value of 0 (zero) is false:`

The Boolean value of **-0** (minus zero) is **false**:

     `var x = -0;
Boolean(x);       // returns false`

The Boolean value of **“” **(empty string) is **false**:

     `var x = "";
Boolean(x);       // returns false`

The Boolean value of **undefined** is **false**:

     `var x;
Boolean(x);       // returns false`

The Boolean value of **null** is **false**:

     `var x = null;
Boolean(x);       // returns false`

The Boolean value of **false** is (you guessed it) **false**:

     `var x = false;
Boolean(x);       // returns false`

The Boolean value of **NaN** is **false**:

     `var x = 10 / "H";
Boolean(x);       // returns false`

## Booleans Can be Objects

Normally JavaScript booleans are primitive values created from literals:

`var x = false;`

But booleans can also be defined as objects with the keyword `new`:

`var y = new Boolean(false);`

### Example

      `var x = false;
var y = new Boolean(false);

// typeof x returns boolean
// typeof y returns object`

Do not create Boolean objects. It slows down execution speed.
The `new` keyword complicates the code. This can produce some unexpected results:

When using the `==` operator, equal booleans are equal:

### Example

      `var x = false;
var y = new Boolean(false);

// (x == y) is true because x and y have equal values`

When using the `===` operator, equal booleans are not equal, because the `===` operator expects equality in both type and value.

### Example

      `var x = false;
var y = new Boolean(false);

// (x === y) is false because x and y have different types`

Or even worse. Objects cannot be compared:

### Example

      `var x = new Boolean(false);
var y = new Boolean(false);

// (x == y) is false because objects cannot be compared`

Note the difference between (x==y) and (x===y).
Comparing two JavaScript objects will always return false.

---

## Complete Boolean Reference

For a complete reference, go to our Complete JavaScript Boolean Reference.

The reference contains descriptions and examples of all Boolean properties and methods.

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