JavaScript Operators

Operators perform mathematical and logical operations on the given operands.

JavaScript has the following types of operators:

• Arithmetic operator

• Assignment operator

• Comparison operator

• Bitwise operator

• Logical operator

• String operator

• Conditional (ternary) operator

• unary operator

• relation operator

JavaScript arithmetic operators

Arithmetic operators are used to perform arithmetic operations on numbers.

Arithmetic operators take numbers as their operands and return a single number.

JavaScript assignment operators

Assignment operators assign values to JavaScript variables.

Simple assignment operator equals (=), it assigns the value of its right operand to its left operand.

JavaScript comparison operators

Comparison operators are used to compare two values and return a boolean value.

The difference between (a == b) and (a === b) is:

• == if a equals b, then return true

• === if a equals b and they belong tosame typethen return true

Comparison operators can be used in conditional statements to compare values and enter different processes based on the result.

Later in this tutorial, you will learn how to use conditional statements.

JavaScript bitwise operators

Bitwise operators treat their operands as a set of32bits (zero and one), rather than decimal, hexadecimal, or octal numbers.

Any number operand in this operation will be converted to32The result is converted back to JavaScript number.

The above example uses4unsigned bit example. But JavaScript uses32signed bit number.

Therefore, in JavaScript, ~5will not return10. It will return-6.

~00000000000000000000000000000101will return11111111111111111111111111111010

JavaScript logical operators

Logical operators are used to determine the logic between variables or values.

Logical operators are usually used to combine conditional statements, and they return boolean values.

JavaScript string operator

The+The operator can also be used for concatenation (concatenation) of strings.

var str1　= "Hello";
var str2　= "World";
var str3　= str1　+　""　+　str2;

Addition assignment operator+= can also be used for concatenation (concatenation) of strings.

var str1　= "Hey! ";
str1　+= "How r u doing?";

When used on strings, the+The operator is called the concatenation operator.

JavaScript conditional (ternary) operator

The conditional operator is the only JavaScript operator that uses three operands.

The syntax is that it can obtain one of two values based on the condition.

condition ? val1　: val2

Ifcondition The result of the calculation istrue, then it will returnval1, otherwise it will returnval2.

You can use the conditional operator at any position where you can use standard operators.

var status = (age >=　18) ? "adult" : "child";

If the age is18If the age is 18 or above, the statement assigns the value 'adult' to the variable status. Otherwise, it assigns the value 'child' to status.

JavaScript unary operators

A unary operation is an operation that has only one operand.

JavaScript includes three unary operators:

Delete operator

The delete operator can remove an object, a property of an object, or an element at a specified index in an array.

If the operation can be performed, the delete operator returns true; otherwise, it returns false. If the operation cannot be performed, it returns false.

If the delete operator succeeds, it sets the property or element to undefined:

var user = {firstName:"Vishal", age:"22, color:"blue"}
delete user.firstName;　　//　returns true

When the delete operator deletes an array element, the element will be removed from the array.

var fruits = ["Apple", "Mango", "Banana"];
delete fruits[0];　　　//　delete "Apple"

typeof operator

The typeof operator returns the type of a variable or expression.

typeof ""　　//　Returns "string"
typeof "Vishal"//　Returns "string"
typeof "42"//　Returns "string" (Number within quotes is String)
typeof　42　　//　Returns "number"
typeof true//　Returns "boolean"
typeof false　　　//　Returns "boolean"
typeof undefined　　　//　Returns "undefined"
typeof null//　Returns "object"
typeof {name:"Vishal", age:22}　//　Returns "object"
typeof [2,　4,　6,　8]//　Returns "object" (not "array", see note below)
typeof function myFunc(){}　//　Returns "function"

Note:The typeof operator returns "object" for arrays because arrays are objects in JavaScript.

This is the list of values returned by the typeof operator:

Void operator

The void operator specifies an expression that requires a value but does not return a value.

The following code creates a hyperlink that does nothing when the user clicks on it.

<a href="javascript:void(0)">Click here to do nothing</a>/a>

JavaScript relational operators

JavaScript has two relational operators:

in operator

If the specified property exists in the specified object, the in operator returns true.

var user = {firstName:"Vishal", age:"22, color:"blue"}
"firstName" in user;　　//　returns true
"age" in user;//　returns true
"Food" in user;　　　//　returns false

When using the in operator with an Array, you must specify the index number, not the value at that index.

var fruits = ["Apple", "Mango", "Banana"];
var item1　= 0 in fruits;　　//　returns true
var item2　=　1　in fruits;　　//　returns true
var item3　=　2　in fruits;　　//　returns true
var item4　=　3　in fruits;　　//　returns false

instanceof operator

If the specified object is of the specified type, the instanceof operator will return true.

Use the instanceof operator when you need to check the type of an object at runtime.

var myObj = new Date();
if (myObj instanceof Date) {
　　　//　statements to execute
}