JavaScript Operators

What operators are?

A JavaScript operator is a symbol or keyword that performs operations on values, variables, or expressions, such as adding numbers, comparing values, assigning data, or checking conditions.

Operators

▻ Arithmetic : - Used for basic math calculations.

+ adds values

let bill = 100; 
let gst = 18; 

let totalBill = bill + gst; 

console.log(totalBill); // 118

- subtracts values

let bill = 500; 
let discount = 50; 

let finalBill = bill - discount; 

console.log(finalBill); // 450

∗ multiplies values

let price = 100; 
let quantity = 3; 

let total = price * quantity; 

console.log(total); // 300

/ divides values

let maxMarks = 500;
let marksGot = 460;

let percentage = (marksGot / maxMarks ) * 100; 

console.log(percentage); //92

% gives remainder

let marks = 47; 

let isOdd = marks % 2; 

console.log(isOdd); // 1

▻ Comparison : - Used to compare two values.

The result is always `true` or `false`.

== Equal to

Checks if two values are equal, but it does not strictly check data type.

let userId = 10; 

console.log(userId == "10"); // true

// Here, JavaScript converts "10" into 10, so the result is true.

=== Strict equal to

Checks both value and data type.

let userId = 10;

console.log(userId === "10"); // false

//Here, 10 is a number and "10" is a string, so the result is false.

!= Not equal to

Checks if two values are not equal.

let price = 100; 

console.log(price != 200); // true

// Here, 100 is not equal to 200, so the result is true.

!= = Strict not equal to

Checks if value or data type is different.

let age = 18; 

console.log(age !== "18"); // true

// Here, 18 is a number and "18" is a string, so the result is true.

> Greater than

Checks if the left value is greater than the right value.

let walletBalance = 1000;
let productPrice = 700;

console.log(walletBalance > productPrice); // true

// Here, 1000 is greater than 700.

< Less than

Checks if the left value is less than the right value.

let stock = 3;
let minimumStock = 5;

console.log(stock < minimumStock); // true

// Here, 3 is less than 5.

>= Greater than or equal to

Checks if the left value is greater than or equal to the right value.

let age = 18;

console.log(age >= 18); // true

// Here, age is exactly 18, so the result is true.

<= Less than or equal to

Checks if the left value is less than or equal to the right value.

let cartItems = 5;
let maxItemsAllowed = 5;

console.log(cartItems <= maxItemsAllowed); // true

// Here, 5 is equal to 5, so the result is true.

▻ Logical: - Check conditions and return true or false.

&& Logical AND

Returns true only when both conditions are true.

let age = 20;
let hasVoterId = true;

console.log(age >= 18 && hasVoterId); // true

//Here, the person is above 18 and also has a voter ID, so the result is true.

A	B	A && B
true	true	true
true	false	false
false	true	false
false	false	false

|| Logical OR

Returns true when at least one condition is true.

let hasEmail = false;
let hasPhoneNumber = true;

console.log(hasEmail || hasPhoneNumber); // true

// Here, email is not available, but phone number is available, so the result is true.

| A | B | A || B | | --- | --- | --- | | true | true | true | | true | false | true | | false | true | true | | false | false | false |

! Logical NOT

Reverses the result.

let isLoggedIn = false;

console.log(!isLoggedIn); // true

// Here, isLoggedIn is false, but ! changes it to true.

A	!A
true	false
false	true

▻ Assignment: - Assign or update values in variables.

= Assign value

Stores a value inside a variable.

let name = "Rahul";

console.log(name); // Rahul

// Here, "Rahul" is assigned to the variable name.

+= Add and assign

Adds a value to the existing variable value.

let walletBalance = 1000;

walletBalance += 500;

console.log(walletBalance); // 1500

// Here, 500 is added to walletBalance.

-= Subtract and assign

Subtracts a value from the existing variable value.

let walletBalance = 1000;

walletBalance -= 300;

console.log(walletBalance); // 700

// Here, 300 is subtracted from walletBalance.

Summary

Arithmetic operators	+ - ∗ / %
Comparison operators	== === != !== > <
Logical operators	&&
Assignment operators	= += -=

Command Palette