While writing code, we often need to calculate prices, compare two passwords, or check if a user is logged in. And we need operators here. An operator in JavaScript is a symbol that performs an action on one or more values and returns a result.

Javascript provided a wide range operators:

But in this blog we are gonna cover four basic operators only i.e.

1. Arithmetic — +, -, *, /, %

2. Comparison — ==, ===, !=, >, <

3. Logical — &&, ||, !

4. Assignment — =, +=, -=

The other 4 (bitwise, ternary, typeof, etc.) are more advanced and will be cover lately.

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Arithemetic Operator:

Whenever you used calculator or apply operation of +,-,*,/,% these all are aritemetic operators. JavaScript does the exact same thing using arithmetic operators.

Here are 5 you need to know about:

Operator	Symbol	What it does
addition	+	adds two number
subtraction	-	subtract two number
multiplication	*	multiply two number
division	/	returns quotient
modulo	%	returns remainder

let a = 10;
let b = 3;

console.log(a + b);  // 13 → Addition
console.log(a - b);  // 7  → Subtraction
console.log(a * b);  // 30 → Multiplication
console.log(a / b);  // 3.33 → Division
console.log(a % b);  // 1  → Modulo (remainder)

⚠️ What is % ? It gives you the remainder after division. So 10 % 3 is 1 because 3 goes into 10 three times, with 1 left over. It's super useful for checking if a number is even or odd.

console.log(10 % 2);  // 0 → even number
console.log(11 % 2);  // 1 → odd number

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Comparison Operator:

Comparision operators compares two values and always returns true or false.

Here are 5 you need to know about:

Operator	Symbol	What it checks
addition	>	greater than
subtraction	<	less than
multiplication	!=	not equal too
division	==	are values equal
modulo	===	are both values and type equal

let a = 10;
let b = 5;

console.log(a > b);   // true  → greater than
console.log(a < b);   // false → less than
console.log(a != b);  // true  → not equal

⚠️NOTE: == & === difference?

Every begineer must fall for this.
== It compares only value.
=== it compares bith value and type

console.log(5 == "5");   // true  → only checks value
console.log(5 === "5");  // false → checks value AND type

== sees 5 and "5" as the same because it only compares the value. === catches that one is a number and the other is a string — so it returns false.

⚠️ Common Mistake: Always use === in your code. == can cause sneaky bugs that are hard to track down. Most professional JavaScript developers avoid == entirely.

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Logical Operator

You can think of logical operator as the words "and", "or", and "not" in plain English.

Here's the simple way to remember each one:

• && — AND — both conditions must be true

• || — OR — at least one condition must be true

• ! — NOT — flips true to false, and false to true

let isLoggedIn = true;
let isAdmin = false;

console.log(isLoggedIn && isAdmin);  // false → both must be true
console.log(isLoggedIn || isAdmin);  // true  → at least one must be true
console.log(!isLoggedIn);            // false → flips the value

A real-world example:

let hasTicket = true;
let isVIP = false;

if (hasTicket && isVIP) {
  console.log("Welcome to the VIP lounge!");
} else {
  console.log("Enjoy the show!");  // this runs
}

💡 This is exactly how real apps work — checking multiple conditions before allowing access.

There is a popular word as Truthtable, while learning about logical operator. It's nothing fancy but shows all the possible outcomes that can be genrated via logical operators.

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Assignment Operator:

Assignment operators are used to assign values or update them with improved syntax.

1. = It's the simplest one which is used to assign values to variable.

//To assign a value
const name = "Mohit"

1. += It assign values after adding as per user instrruction.

let num = 10;
// if you want to add 5 to nums then you can write
// num = num + 5;

//via Assignment operators - more professional ans short
num += 5;
console.log(num);    //15

Here num += 5 is nothing special but num = num + 5.

Other operator can be written in same way:

let num = 10;

//subtraction
num -= 5;            // num = num - 5;
console.log(num)    //5

//multiplication
num *= 2;            // num = num * 2;
console.log(num)    //10

//division
num *= 5;            // num = num / 5;
console.log(num)    //50

//modulo
num %= 2;            // num = num % 2;
console.log(num)    //0