Operators in JavaScript

Operators in JavaScript allow you to perform operations on data such as calculations, comparisons, logical checks, and assignments. They are a fundamental part of working with variables and values, enabling you to write dynamic, readable, and functional code.

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Arithmetic Operators in JavaScript

Arithmetic operators are used to perform basic mathematical operations on numeric values.

List of JavaScript Arithmetic Operators

Operator	Description	Example	Output
+	Addition	5 + 3	8
-	Subtraction	10 - 4	6
*	Multiplication	6 * 3	18
/	Division	15 / 3	5
%	Modulus (Remainder)	17 % 5	2
++	Increment	let x = 5; x++	6
--	Decrement	let y = 5; y--	4

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Arithmetic Operator Examples

let x = 10;
let y = 3;

console.log(x + y); // Output: 13
console.log(x - y); // Output: 7
console.log(x * y); // Output: 30
console.log(x / y); // Output: 3.3333333333333335
console.log(x % y); // Output: 1
console.log(x ** y); // Output: 1000

Increment and Decrement Behavior

• x++ or x--: value changes after evaluation
• ++x or --x: value changes before evaluation

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Comparison Operators in JavaScript

Comparison operators compare two values and return a Boolean value (true or false). They are commonly used in conditional logic.

JavaScript Comparison Operator Reference

Operator	Description	Example	Output
==	Equal to	5 == '5'	true
===	Strict equal (value + type)	5 === '5'	false
!=	Not equal	5 != '6'	true
!==	Strict not equal	5 !== '5'	true
>	Greater than	10 > 5	true
<	Less than	3 < 7	true
>=	Greater than or equal	8 >= 8	true
<=	Less than or equal	4 <= 3	false

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Comparison Operator Examples

let a = 5;
let b = '5';

console.log(a == b);   // true (loose equality)
console.log(a === b);  // false (strict equality)
console.log(a != b);   // false
console.log(a !== b);  // true
console.log(a > 3);    // true
console.log(a < 10);   // true
console.log(a >= 5);   // true
console.log(a <= 4);   // false

Difference Between == and ===

• == compares values only
• === compares both value and type (recommended)

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Logical Operators in JavaScript

Logical operators are used to combine or invert Boolean values and expressions.

JavaScript Logical Operators

Operator	Description	Example	Output
&&	Logical AND	true && false	false
`		`	Logical OR
!	Logical NOT	!true	false

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Logical Operator Examples

let isAdult = true;
let hasPermission = false;

let canEnter = isAdult && hasPermission; // false
let canView = isAdult || hasPermission;  // true
let isDenied = !hasPermission;           // true

Logical Operator Behavior

• && → true only if both conditions are true
• || → true if at least one condition is true
• ! → reverses the Boolean value

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Assignment Operators in JavaScript

Assignment operators assign values to variables and include shorthand forms for updating values.

JavaScript Assignment Operators

Operator	Description	Example	Equivalent
=	Assignment	x = 10	–
+=	Addition assignment	x += 5	x = x + 5
-=	Subtraction assignment	x -= 3	x = x - 3
*=	Multiplication assignment	x *= 2	x = x * 2
/=	Division assignment	x /= 4	x = x / 4
%=	Modulus assignment	x %= 2	x = x % 2

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Assignment Operator Examples

let x = 10;

x += 5;
console.log(x); // 15

x -= 3;
console.log(x); // 12

x *= 2;
console.log(x); // 24

x /= 4;
console.log(x); // 6

x %= 3;
console.log(x); // 0

x = 2;
x **= 3;
console.log(x); // 8

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Conditional (Ternary) Operator in JavaScript

The ternary operator provides a concise alternative to an if-else statement.

Ternary Operator Syntax

let result = condition ? valueIfTrue : valueIfFalse;

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Basic Ternary Operator Example

let age = 20;
let access = age >= 18 ? "Allowed" : "Denied";

console.log(access); // Output: "Allowed"

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Nested Ternary Operator Example

let score = 85;
let grade = score >= 90 ? 'A' : score >= 80 ? 'B' : 'C';

console.log(grade); // Output: "B"

⚠️ Best Practice:
Avoid excessive nesting of ternary operators as it reduces readability. Use if-else when logic becomes complex.

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Summary of JavaScript Operators

JavaScript provides a rich set of operators to handle calculations, comparisons, logic, and assignments:

• Arithmetic operators perform mathematical operations
• Comparison operators evaluate conditions
• Logical operators combine or invert Boolean expressions
• Assignment operators simplify value updates
• Ternary operator offers a concise conditional syntax

Understanding and using these operators effectively is essential for writing clear, expressive, and efficient JavaScript code.