Boolean Javascript

| | | | | | |

How to use JavaScript booleans

True or false values ‚Äã‚Äãare everywhere in programming. We call these Boolean values. They can be used to compare two or more values ‚Äã‚Äãand check which parts of a program should run.

In this guide, we’ll talk about what Booleans are and how they work. We’ll see some examples of using JavaScript Boolean to get you started.

What is a JavaScript Boolean?

A Boolean is a value which can be True or False.

Booleans are named after George Boole, a famous mathematician associated with the advancement of the study of mathematical logic. This means that Booleans are always in upper case.

Any object with a value in JavaScript is true. Anything that has no value is wrong.

The following values ‚Äã‚Äãare all true:

  • 10
  • " Hello "
  • True < / li>

Any null, false, undefined, 0, NaN, or empty string value is considered false.

Let & rsquo; s explains how Booleans can be used in JavaScript !

Using booleans to make comparisons

There can only be two results of a comparison: true or false. This means that we can use booleans to evaluate the result of a comparison.

JavaScript uses comparison operators to compare two values. They are:

  • ==: same as
  • ! =: different from
  • >: greater than
  • <: less than
  • <=: less than or equal to
  • > =: greater than or equal to

When using the last two operators in the list above, you need to make sure you arrange the panels in the correct order. JavaScript will not understand your code if you return the signs.

Costruiremo un programma che valuti the età di due studenti in a class di scuola superior. Let’s start by checking if a student, Alex, is older than another student, Lisa:

Our code returns: true.

Alex is 16 and Lisa is 15. This means that Alex is older than Lisa. We can use any comparison operator to evaluate how to compare two variables . Let’s see if Alex is the same age as another student, Paul:

This code checks if the value of "alex" is equal to the value of "paul". These two students are 16 years old. Our code returns: true.

Strings can be evaluated using JavaScript Booleans.

Let’s check if student Lisa is on the honor roll this month:

Our code returns: false. We check if the value of "honor_roll" is equal to the value of "student". The student on the honor roll is Alex. This means that when we compare our two strings, false is returned. If Lisa was on the honor roll, our code would return true.

We can assign the result of this comparison to a Boolean variable:

Our code returns: true. This code performs the same comparison. The value of the Boolean object comparison is stored in the variable "is_honor_roll_student". We then print the value of this variable to the console.

Using Booleans with Logical Operators

Logical operators are generally used to evaluate two or more expressions. They allow you to check if two or more statements are true, if one of the two statements is true or if one or more statements are false.

There are three logical operators that can be used with functions booleans:

Let’s create a program that checks if it’s possible to buy a new computer game in an online store. We will first check if a customer has a sufficiently high gift card balance on your account or if a customer has a credit card that can be charged for the computer:

This code checks if the customer has enough money in a gift card or if the customer has a card associated with your account. Our code returns: true.

The customer does not have enough money on the e gift card balance. They have a card attached to their account. Because one of the two expressions we specified is true, the expression returns true.

The game you are purchasing is rated 18+. Let’s check if a customer is over 18 and has enough money to buy the game:

Our code returns: true. We used the && operator to check if both of our conditions are met. They are satisfied, so our code returns true.

We can use the not operator to test if an expression is false. Let’s see if our client has already bought a game:

This code checks if our customer has already purchased a game. We use the operator not ("!‚") to reverse the result of purchases == 0. This means that if a customer has already purchased a game, our expression will be evaluated as true.

use booleans with an if statement

Booleans are used to control the flow of a program. this means that you can use a Boolean value to determine whether a block of code should be executed.

This code snippet will print a message to the console if a customer has sufficient balance on a gift card to purchase a game:

This code returns: This gift card has an insufficient balance.

Our code assesses whether the customer’s balance is equal to or greater than the cost of the game or. If the customer has enough money, the code inside our ‚"if‚" instruction is executed . Otherwise, the code inside our else statement is executed.

Let’s see what happens when we change the value of "balance" to $ 32.50:

Our code returns: This gift card has enough money

Conclusion

Boolean value can store a true or false value. Booleans are commonly used to evaluate whether an expression es t true or false. You can use a Boolean with an if statement to execute a block of code depending on whether or not an expression returns a certain Boolean value.

You are now ready to start using Boolean JavaScript like an expert developer !

center ; -moz-box-pack: center ; justify-content: center ; text-transform: uppercase ; max-width: 350px ; margin: auto ; margin-top: 30px ; background: rgb (60 145 230) no scroll repeat 0 % 0 % / 200 %}. testimonial-section-1 img {border-radius: 100px ; padding-bottom: 10px}. testimonial-section img {width: 100px; height: 100px; border-radius: 100px ; margin-bottom: 20px}

Our code returns: true. We used the && operator to check if both of our conditions are met. They are satisfied, so our code returns true.

We can use the not operator to test if an expression is false. Let’s see if our client has already bought a game:

This code checks if our customer has already purchased a game. We use the operator not ("!") to reverse the result of purchases == 0. This means that if a customer has already purchased a game, our expression will be evaluated as true.

Using booleans with an if statement

Booleans are used to control the flow of a program. This means that you can use a boolean to determine if a certain block of code should be executed. < br>

This code snippet will print a message to the console if a customer has enough balance on a gift card to purchase a game:

This code returns: This gift card has a balance insufficient.

Our code assesses the client’s balance is equal to or greater than the cost of the game or. If the client has enough money, the code inside our ‚"if‚" statement is executed . Otherwise, the code in our other statement is executed

Let’s see what happens when we change the value of "balance" to $ 32.50.

Our code returns: This gift card has enough money

Conclusion

Boolean value can store a true value or false. . Booleans are commonly used to evaluate whether an expression is true or false. You can use a Boolean with an if statement to execute a block of code depending on whether or not an expression returns a certain Boolean value.

You are now ready to start using boolean JavaScript as an expert developer

center, -moz-box-pack: center, justify content: center; text-transform: upper case; max-width: 350px; margin: auto; margin-top: 30px; . background: rgb (60145230) no scroll repetition 0% 0% / 200%} appreciation section-1 img {border-radius: 100px; -bas padding: 10px} img .testimonial section {width: 100px; height: 100px; border-radius: 100px ; margin-bottom: 20px}

Our code returns: true. We used the && operator to check if both of our conditions are met. They are satisfied, so our code returns true.

We can use the not operator to test if an expression is false. Let’s see if our client has already bought a game:

This code checks if our customer has already purchased a game. We use the operator not ("!") to reverse the result of purchases == 0. This means that if a customer has already purchased a game, our expression will be evaluated as true.