JavaScript Operators: The Basics You Need to Know

Just like we need operators to do mathematics in real life, we also need them in any programming language. In JavaScript too.

In JS we have arithmetic operators. We also have more operators for validation and logic like comparison operators, logical operators and assignment operators.

Let’s deep dive into this pool of operators.

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What Operators Are

To perform arithmetic operations we use certain symbols. For addition we use +, for subtraction we use - and so on. These symbols are called operators.

In simple words, operators are special symbols that perform operations on values.

They tell JavaScript what action to perform.

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Arithmetic Operators

As now we know what operators are, let’s start with math operators.

In JavaScript we use:

+ for addition
- for subtraction
* for multiplication
/ for division
% for remainder

Let’s understand each with examples.

let num1 = 10;
let num2 = 3;

console.log(num1 + num2); // 13
console.log(num1 - num2); // 7
console.log(num1 * num2); // 30
console.log(num1 / num2); // 3.333...
console.log(num1 % num2); // 1

The % operator gives remainder.

10 divided by 3 leaves remainder 1, so that’s what it returns.

These are the operators you will use almost daily.

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Comparison Operators

To validate data through comparison, JavaScript provides comparison operators:

==, ===, !=, !==, <, >

These operators compare two values and return a Boolean value, which means either true or false.

There’s a catch between == and ===.

== checks only the value.
=== checks both value and type. It is a strict check.

Let’s see it clearly.

console.log(5 == "5");  // true
console.log(5 === "5"); // false

Why?

Because in the first case == only checks the value. 5 and "5" are treated as equal.

But in the second case === checks type also. One is number and the other is string. So it returns false.

That’s why in real projects we prefer === because it is more strict and safer.

Now look at not equal operators.

console.log(5 != 10);   // true
console.log(5 !== "5"); // true

!= checks value only.
!== checks value and type.

Now greater than and less than.

console.log(10 > 5); // true
console.log(3 < 1);  // false

Comparison operators always return true or false.

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Logical Operators

There are three main logical gates.

AND
OR
NOT

To perform these logical operations JavaScript gives us:

&& for AND
|| for OR
! for NOT

Let’s understand each.

AND ( && )

AND means both conditions must be true.

let age = 20;
let hasId = true;

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

If both sides are true, result is true.
If one is false, result becomes false.

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OR ( || )

OR means at least one condition must be true.

let isAdmin = false;
let isEditor = true;

console.log(isAdmin || isEditor); // true

If one condition is true, result becomes true.

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NOT ( ! )

NOT reverses the value.

let isLoggedIn = false;

console.log(!isLoggedIn); // true

If value is true, it becomes false.
If value is false, it becomes true.

Logical operators are mostly used in conditions.

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Assignment Operators

To assign value to a variable we use =

let score = 10;

But JavaScript also gives shortcut assignment operators like += and -=

Example:

let points = 5;

points += 3; // points = points + 3
console.log(points); // 8

points -= 2; // points = points - 2
console.log(points); // 6

These operators help us update values easily.

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Let’s Try Everything Together

Now let’s perform some operations practically.

let a = 15;
let b = 5;

console.log("Addition:", a + b);
console.log("Subtraction:", a - b);
console.log("Multiplication:", a * b);
console.log("Division:", a / b);
console.log("Remainder:", a % b);

Now compare values using both == and ===

let value1 = 10;
let value2 = "10";

console.log(value1 == value2);  // true
console.log(value1 === value2); // false

Now write a small condition using logical operators.

let age = 19;
let hasPermission = true;

if (age > 18 && hasPermission) {
  console.log("Access granted");
}

Here both conditions must be true for access.

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Operator Categories Overview

You can think of operators in simple groups:

Arithmetic → Do math
Comparison → Compare values
Logical → Combine conditions
Assignment → Assign or update values

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Operators are the backbone of logic in JavaScript.

Without operators we cannot:

Do calculations
Compare values
Write conditions
Update variables