Logical Operators Part 1

Part of the Fundamentals section of Coddy's JavaScript journey — lesson 18 of 77.

Logical operators are used to check combinations of comparisons that return true or false.

For example, the following statement contains two comparisons:

Is 5 greater than 3 and less than 6?

Operator	Meaning	Example
`&&`	And - `true` if all operands are `true`	`a && b`
`\|\|`	Or - `true` if any operand is `true`	`a \|\| b`
`!`	Not - `true` if the operand is `false`	`!a`

Let's see some examples:

5 is greater than 3, and 1 equals 1:

let b1 = (5 > 3) && (1 == 1); // holds true

Explanation: All of the operands are true, so b1 will hold true (&& operation is true if both operands are true) .

5 is not equal to 4, or five equals to 2:

let b2 = !(5 == 4) || (5 == 2); // holds true

Explanation: The first operand (5 != 4) is true so b2 is also true (|| operation is true if either one of the operands is true)

1 is not equal to 1 or false:

let b3 = !(1 == 1) || false; // holds false

Explanation: All of the operands are false, so b3 will hold false (|| operation).

not (3 greater than 4):

let b4 = !(3 > 4); // holds true

Explanation: The operand is false, so b4 will hold true (! operation).

not (5 greater than 10 or 5 greater than 1):

let b5 = !(5 > 10 || 5 > 1); // holds false

Explanation: 5 > 10 || 5 > 1 is true (one of the operands is true), so in total b5 is false (! operation).

Challenge

Beginner

You are given a code. Replace the question marks of the variables b1 and b2 so that b3 holds true.

There are many right solutions.

Try it yourself

// Type your code below
let b1 = ?
let b2 = ?
let b3 = b1 || b2

// Don't change the line below
console.log(`b3 = ${b3}`)

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

4Operators Part 2

7Bill Split Calculator

10FizzBuzz with a Twist

13Grocery List Tracker