JavaScript
Operators

What are Operators in JavaScript?

Operators in JavaScript are special symbols used to perform operations on operands (values or variables). Think of them as tools that help you calculate, compare, assign, or manipulate data in your program.

Types of JavaScript Operators

• Arithmetic Operators
• Assignment Operators
• Comparison Operators
• Logical Operators
• Unary Operators
• Bitwise Operators
• Ternary Operator
• Type Operators

Arithmetic Operators

These operators perform basic mathematical operations:

• + Addition
• - Subtraction
• * Multiplication
• / Division
• % Modulus (Remainder)
• ** Exponentiation (Power)

Example:

let a = 10;
let b = 3;

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

Addition: 13
Subtraction: 7
Multiplication: 30
Division: 3.3333333333333335
Modulus: 1
Exponentiation: 1000
    

Assignment Operators

These assign values to variables. You can also use them to perform operations and assign the result in one step:

• = Assign
• += Add and assign
• -= Subtract and assign
• *= Multiply and assign
• /= Divide and assign
• %= Modulus and assign

Example:

let x = 5;
x += 3; // x = x + 3
console.log("After += 3:", x);
x *= 2; // x = x * 2
console.log("After *= 2:", x);
    

After += 3: 8
After *= 2: 16
    

Comparison Operators

Used to compare two values. Returns a Boolean value (true/false):

• == Equal to (loose equality)
• === Equal value and type (strict equality)
• != Not equal (loose)
• !== Not equal (strict)
• > Greater than
• < Less than
• >= Greater than or equal
• <= Less than or equal

Example:

console.log(5 == "5");    // true (type coercion)
console.log(5 === "5");   // false (different types)
console.log(10 > 7);      // true
console.log(3 <= 2);      // false
    

true
false
true
false
    

Logical Operators

Used to combine multiple conditions:

• && Logical AND
• || Logical OR
• ! Logical NOT

Example:

let isLoggedIn = true;
let hasPermission = false;

console.log("Can access?", isLoggedIn && hasPermission);
console.log("Partial access?", isLoggedIn || hasPermission);
console.log("Not logged in?", !isLoggedIn);
    

Can access? false
Partial access? true
Not logged in? false
    

Unary Operators

Works with only one operand.

• + Unary plus (converts to number)
• - Unary minus (negates)
• ++ Increment
• -- Decrement
• typeof Returns the data type

Example:

let y = "5";
console.log(typeof +y);  // number
let count = 1;
console.log(++count);    // 2
    

number
2
    

Ternary Operator

This is a shortcut for if-else condition. Syntax: condition ? valueIfTrue : valueIfFalse

Example:

let age = 20;
let status = age >= 18 ? "Adult" : "Minor";
console.log("Status:", status);
    

Status: Adult
    

Type Operators

• typeof - Returns a string indicating the type of the operand
• instanceof - Checks if an object is an instance of a specific class

Example:

let text = "Hello";
console.log(typeof text); // string

let today = new Date();
console.log(today instanceof Date); // true
    

string
true
    

Beginner Tip

Q: What’s the difference between == and === in JavaScript?

A: == compares only values (performs type coercion), while === compares both value and type. Always prefer === to avoid unexpected bugs.

Q: Why use the ternary operator when we already have if-else?

A: Ternary operator is useful for quick decisions or assignments. It makes the code concise but use it wisely to maintain readability.