Operators

Operators in JavaScript

Operators in JavaScript are symbols or keywords used to perform operations on values and variables. They allow us to perform calculations, compare values, assign values, combine conditions, and perform other operations in a program.

For example:

let a = 10;
let b = 5;

console.log(a + b);

Output:

15

Here, + is an operator used to add two values.

JavaScript provides different types of operators, such as Arithmetic, Assignment, Comparison, Logical, Increment and Decrement, and Ternary operators.

1. Arithmetic Operators

Arithmetic operators are used to perform mathematical operations on numbers.

Operator	Name	Example	Result
+	Addition	10 + 5	15
-	Subtraction	10 - 5	5
*	Multiplication	10 * 5	50
/	Division	10 / 5	2
%	Modulus	10 % 3	1
**	Exponentiation	2 ** 3	8

Example

let a = 10;
let b = 3;

console.log(a + b);
console.log(a - b);
console.log(a * b);
console.log(a / b);
console.log(a % b);
console.log(a ** b);

Output:

13
7
30
3.3333333333333335
1
1000

The % operator returns the remainder of a division, while the ** operator is used to calculate the power of a number.

2. Assignment Operators

Assignment operators are used to assign values to variables.

The basic assignment operator is =.

let age = 20;

console.log(age);

Output:

20

JavaScript also provides compound assignment operators.

Operator	Example	Equivalent To
=	a = 10	a = 10
+=	a += 5	a = a + 5
-=	a -= 5	a = a - 5
*=	a *= 5	a = a * 5
/=	a /= 5	a = a / 5
%=	a %= 5	a = a % 5

For example:

let a = 10;

a += 5;

console.log(a);

Output:

15

Here, a += 5 is the same as a = a + 5.

3. Comparison Operators

Comparison operators are used to compare two values. The result of a comparison is always a Boolean value: true or false.

Operator	Meaning
==	Equal to
===	Strictly equal to
!=	Not equal to
!==	Strictly not equal to
>	Greater than
<	Less than
>=	Greater than or equal to
<=	Less than or equal to

For example:

let a = 10;
let b = 5;

console.log(a > b);
console.log(a < b);
console.log(a === b);

Output:

true
false
false

== vs ===

The == operator compares values after performing type conversion when necessary, while === compares both the value and the data type without performing type conversion.

console.log(10 == "10");
console.log(10 === "10");

Output:

true
false

4. Logical Operators

Logical operators are used to combine two or more conditions. They return a Boolean result, either true or false.

JavaScript has three main logical operators:

Operator	Name	Meaning
&&	Logical AND	Returns true only when both conditions are true.
OR	Logical OR	Returns true when at least one condition is true.
!	Logical NOT	Reverses the result. true becomes false, and false becomes true.

Logical AND &&

The && operator returns true only when both conditions are true.

let age = 25;

console.log(age > 18 && age < 30);

Output:

true

Here, both conditions are true, so the result is true.

Logical OR ||

The || operator returns true when at least one condition is true.

let age = 25;

console.log(age < 18 || age > 20);

Output:

true

The second condition is true, so the overall result is true.

Logical NOT !

The ! operator reverses a Boolean value.

let isStudent = true;

console.log(!isStudent);

Output:

false

Because the original value is true, the ! operator changes it to false.

5. Increment and Decrement Operators

The increment operator ++ increases a value by 1, while the decrement operator -- decreases a value by 1.

Increment Operator

let count = 5;

count++;

console.log(count);

Output:

6

Decrement Operator

let count = 5;

count--;

console.log(count);

Output:

4

Both operators can be used in prefix and postfix forms.

let a = 5;

console.log(++a);

Output:

6

6. Ternary Operator

The ternary operator is a short way of writing a simple if...else condition. It uses three parts: a condition, a value when the condition is true, and a value when the condition is false.

The syntax is:

condition ? valueIfTrue : valueIfFalse;

For example:

let age = 20;

let result = age >= 18 ? "Adult" : "Minor";

console.log(result);

Output:

Adult

Here, the condition age >= 18 is true, so "Adult" is assigned to result.

7. String Operator

The + operator can also be used to combine strings. This process is called string concatenation.

let firstName = "John";
let lastName = "David";

let fullName = firstName + " " + lastName;

console.log(fullName);

Output:

John David

Here, the + operator combines the strings together.