The **JavaScript **programming language offers different **operators **to evaluate expressions based on boolean variables. These operators help to maintain the programming flow control with respect to the added mathematical logic. More specifically, **JavaScript Boolean operators** allow you to perform different comparisons on the specified variables and evaluate the results.

This write-up will explain the working of the **JavaScript Boolean operators**. So, let’s start!

**JavaScript Boolean Operators**

Here is the list of Boolean operators supported by JavaScript:

- Boolean
**OR**“**||**” operator - Boolean
**AND**“**&&**” operator - Boolean
**NOT**“**!**” operator

We will now discuss the usage of each of the mentioned JavaScript Boolean operators in the following sections.

**How to use JavaScript Boolean OR operator**

In JavaScript, the **Boolean **“**OR**” **operator **is utilized to evaluate boolean variables’ values. It is represented using the **double pipe **operator “**||**”.

While using the Boolean “**OR**” operator, If the value of both of the specified variables is “**true**,” then the expression is considered as “**truthy**,” and it will return “**true**” value; otherwise, the return case of the **OR operator** will be set to “**false**”.

### Syntax of JavaScript Boolean OR operator

Here, the Boolean OR operator “**||**” will evaluate the expression “**x || y**” based on their values and store the returned value in the “**result**” variable.

**Truth table of JavaScript Boolean OR operator**

The below-given truth table illustrates the OR operator result based on the specified values of “**x**” and “**y**” boolean variables:

x |
y |
x || y |

true | true | true |

true | false | true |

false | true | true |

false | false | false |

According to the truth table, if the value of any operand is “**true**”, the Boolean OR operator “**||**” will mark the expression as “**true**” in case both values are “**false**,” then the OR operator will also return a “**false**” value.

Now, let’s check out a practical example of implementing the functionality of the JavaScript Boolean OR operator.

**Example: How to use JavaScript Boolean OR operator**

First of all, we will create two boolean variables named “**x**” and “**y**” having the following values:

y = false;

Next, we will use the Boolean OR operator “**||**” for evaluating the values of “**x**” and “**y**”:

Execution of the provided code will return “**true**” because the value of one of the specified boolean variables is “**true**”:

In case, if the values of both “**x**” and “**y**” variable is “**false**”, then the expression “**x || y**” will return “**false**”:

y = false;

console.log(x || y);

** Output**

**How to use JavaScript Boolean AND operator**

Like the OR operator, the **JavaScript Boolean AND operator** is also used to evaluate the values of added boolean variables. It is represented by using double **ampersand **“**&&**” sign.

While utilizing JavaScript Boolean **AND **operator, if both values are “**true**,” the expression is considered “**truthy**.” In the other case, if either of one value is “**false**“, the return case of AND operator will be set to “**false**”.

**Syntax of JavaScript Boolean AND operator**

Here, the Boolean AND operator “**&&**” will evaluate the expression “**x && y**” based on their values and store the returned value in the “**result**” variable.

**Truth table of JavaScript Boolean OR operator**

Now, check out the following truth table of the JavaScript Boolean AND operator to understand how it works:

x |
y |
x && y |

true | true | true |

true | false | false |

false | true | false |

false | false | false |

According to the above-given truth table if any value of the operand is “**false**”, then after evaluating the expression, the AND operator “**&&**” will return a “**false**” value, in case both values are set as “**true**,” the AND operator will mark the expression as “**true**”.

**Example: How to use JavaScript Boolean AND operator**

In the following example, the boolean variable “**x**” comprises a “**true**” value and “**y**” is initialized with “**false**”:

y = false;

console.log(x && y);

The “**x && y**” expression will return “**false**” after checking the value of the “**y**” variable:

In the other case, when both of the variables contain “**true**” as their value, then the Boolean AND operator will also return “**true**”:

y = true;

console.log(x && y);

**Output**

**How to use JavaScript Boolean NOT operator**

The JavaScript **Boolean NOT operator** is used to **inverse **the value of an operand, and it is represented by an exclamation mark “**!**”.

**Syntax of JavaScript Boolean NOT operator**

Here, the NOT operator will inverse the value of the “**x**” variable in such a way that if its value is “**true**”, the NOT operator will change it to “**false**.” If it already has a “**false**” value, then the resultant value of “!**x**” will be “**true**”.

**Truth Table of JavaScript Boolean NOT operator**

Based on the values of the “**x**” variable, the corresponding “**!x**” will work as follows:

x |
!x |

undefined | true |

null | true |

NaN | true |

Object {} |
false |

Empty string “ “ |
true |

Non-empty string | false |

Number other than 0 |
false |

**Example: How to use JavaScript Boolean NOT operator**

Now, we will utilize the JavaScript Boolean NOT operator to inverse the values of the given “**x**” and “**y**” boolean variables:

y = false;

console.log(!x);

console.log(!y);

As you can see from the output, the values returned by the Boolean NOT operator are opposite to the original values of “**x**” and “**y**”:

That was all essential information related to the usage of JavaScript Boolean Operators. Explore them further according to your preferences.

## Conclusion

The **JavaScript Boolean OR (||) operator**,** Boolean AND operator (&&)**, and **Boolean NOT (!) operator** are used to perform different types of comparison on the specified variables and evaluate the results. The JavaScript NOT operator inverse the value of a boolean variable, whereas the return case of the Boolean OR and AND operators depend upon the specified variables’ values. This write-up explained the usage of the JavaScript Boolean operators.