Operators in Javascript

Arithmetic operators in JavaScript

Arithmetic operations are performed on the operands using the arithmetic operators. Let's go through the list of arithmetic operators in JavaScript.

Note on increment and decrement operator: 

• The increment/decrement operator can only be applied to variables not on integers directly.
• When the operator goes after the variable, it is in the postfix form. In the postfix form, the value is incremented, but the previous value is used.
• When the operator goes before the variable, it is in the prefix form. In the prefix form, the value is decremented, but the previous value is used.

Example

let num1 = 10;
let num2 = 5;

// addition
console.log("num1 + num2: " + (num1 + num2));

// subtraction
console.log("num1 - num2: " + (num1 - num2));

// multiplication
console.log("num1 * num2: " + (num1 * num2));

// division
console.log("num1 / num2: " + (num1 / num2));

// remainder
console.log("num1 % num2: " + (num1 % num2));

// increment operator
console.log("num1++: " + num1++);

// decrement operator
console.log("num1--: " + num1--);

// power
console.log("num1 ** num2: " + (num1 ** num2));

Output

num1 + num2: 15

num1 - num2: 5

num1 * num2: 50

num1 / num2: 2

num1 % num2: 0

num1++: 10

num1--: 11

num1 ** num2: 100000

Comparison operators in JavaScript

They are used to compare the two operands, and the result is always true or false. Let's go through the list of comparison operators in JavaScript.

Example

let val1 = 10;
let val2 = 5;
let val3 = "10";
let val4 = 15;

// equal to operator
console.log("val1 == val3: " + (val1 == val3));

// strict equal to operator
console.log("val1 === val3: " + (val1 === val3));

// not equal to operator
console.log("val1 != val2: " + (val1 != val2));

// strict not equal to operator
console.log("val1 !== val3: " + (val1 !== val3));

// greater than operator
console.log("val1 > val2: " + (val1 > val2));

// greater than or equal operator
console.log("val1 >= val4: " + (val1 >= val4));

// lesser than operator
console.log("val1 < val4: " + (val1 < val4));

// lesser than or equal operator
console.log("val1 <= val2: " + (val1 <= val2));
 

Output

val1 == val3: true

val1 === val3: false

val1 != val2: true

val1 !== val3: true

val1 > val2: true

val1 >= val4: false

val1 < val4: true

val1 <= val2: false

Bitwise operators in JavaScript

They are used to perform Bitwise operations on operands. Let's go through the list of bitwise operators in JavaScript.

Example

let num1 = 0;
let num2 = 1;

// bitwise AND  operator
console.log("num1 & num2:" + (num1 & num2));

// bitwise OR operator
console.log("num1 | num2:" + (num1 | num2));

// bitwise XOR operator
console.log("num1 ^ num2:" + (num1 ^ num2));

// bitwise NOT operator
console.log("~num1:" + (~num1));

// bitwise left shift operator
console.log("num2<<1: " + (num2<<1));

// bitwise right shift operator
console.log("num2>>1: " + (num2>>1));

// bitwise zero-fill right shift operator
console.log("num2>>>1: " + (num2>>>1));

Output
num1 & num2:0

num1 | num2:1

num1 ^ num2:1

~num1:-1

num2<<1: 2

num2>>1: 0

num2>>>1: 0

Read about Bitwise Operators in C here.

Logical operators in JavaScript

Logical operations like AND, OR, and NOT are performed on the operands using the logical operators. Let's go through the list of logical operators in JavaScript.

Example

let val1 = true;
let val2 = false;

// logical and operator 
console.log("val1 && val2: "+ (val1 && val2));

// logical or operator
console.log("val1 || val2: "+ (val1 || val2));

// logical not operator
console.log("!val1: "+ (!val1));

Output

val1 && val2: false

val1 || val2: true

!val1: false

Assignment operators in JavaScript

They are used to assign values to the operand. Let's go through some of the assignment operators in JavaScript.

Example
 

// assignment operator
let num1 = 5;

// addition operator
num1 += 2;
console.log("num1: "+ num1);

// subtraction operator
num1 -= 8;
console.log("num1: "+ num1);

// multiplication operator
num1 *= 2;
console.log("num1: "+ num1);

// division operator
num1 /= 5;
console.log("num1: "+ num1);

Output

num1: 7

num1: -1

num1: -2

num1: -0.4

String operators in JavaScript

On strings apart from the comparison operators, the concatenation operator (+) can be used. The concatenation operator concatenates two string values together and returns a new string. 

Example
 

let str1 = "Coding";
let str2 = "Ninjas";

// comparison operator
console.log("str1 === str2: "+ (str1 === str2));

// concatenation operator
let resultStr = str1 + " " + str2;
console.log(str1 + " " + str2 + ": " + resultStr);

Output
str1 === str2: false

Coding Ninjas: Coding Ninjas

Comma operator in JavaScript

The comma operator "," evaluates the operands and returns the value of the last operand. It is mainly used inside a for loop to allow multiple variables to be updated each time through the loop.  

Example
 

// a is assigned with the last value
let a = (1, 2, 3);
console.log("a: " + a);

let arr =  [
   [1, 2, 3],
   [4, 5, 6],
   [7, 8, 9],
]

console.log("Array before updation: ");
for(let i = 0 ; i < 3 ; i++)
   console.log(arr[i]);

// comma operator to updates two variables at once
for (let i = 0, j = 0; i < 3; i++, j++)
 arr[i][j] += 1;

console.log("Array after left diagonal elements are updated by 1: ");
for(let i = 0 ; i < 3 ; i++)
   console.log(arr[i]);

Output

a: 3

Array before updation: 

[ 1, 2, 3 ]

[ 4, 5, 6 ]

[ 7, 8, 9 ]

Array after left diagonal elements are updated by 1: 

[ 2, 2, 3 ]

[ 4, 6, 6 ]

[ 7, 8, 10 ]

Operator Precedence

The execution order is defined by the operator precedence order when an expression has more than one operator. Operator precedence can be overridden using parentheses.

The following table describes the operator precedence order, from highest to lowest.

You can practice by yourself with the help of an online javascript compiler.

Frequently Asked Questions

Q. What is the logical operator for or JavaScript?

In Javascript, the logical OR is represented as || operator. The OR operator returns true if any one of its operands is true and false if both the operands are false. 

Q. What is the === operator in JavaScript?

=== Operator is used for the comparison. The strict equality "===" is used to compare the value and type of the operands. It checks for both the value as well as the data type for the operands. 

Q. What does || mean in coding?

|| is a Logical OR operator. This operator returns a boolean value. It returns true if any one of the operands is true and false when both the operands are false. 

Q. How to add 2 conditions in if statement in JavaScript?

To add two conditions in an if statement in JavaScript, you can make use of OR(||), AND(&&) or Not(!) operators. These operators helps in defining two conditions together in an if statement. 

Conclusion

The blog covered the various operators in JavaScript, namely, arithmetic operators, comparison operators, bitwise operators, logical operators, assignment operators, string operators, and the comma operator. The precedence order of the operators has also been covered.
 Now that you know the concept of variables and data types in Javascript, go ahead and try out some questions based on them on our Coding Ninjas Studio Platform!
To learn more about Micro Operations, refer to Arithmetic Micro Operations.

Don't stop here. Check out our Basics of JavaScript - guided path to learn JavaScript from scratch. If you are preparing for JavaScript Interviews, check out the blog Javascript Interview Questions.

We hope you found this blog useful. Feel free to let us know your thoughts in the comments section.