Operators in JavaScript with Examples

For example,

5 + 7 = 12

The + (plus sign) here, is an operator (an arithmetic operator), the number 5 is the left operand and the value 7 is the right operand.

In JavaScript, you can assign the data values (or the operands) to "variables" and apply an "operator" to get a result, or you can simply use numbers along with an operator and get the result. For example,

<script>
    var a = 5;
    var b = 7;
    var c = a + b;
    alert (c);

// Using ES6 features.
    // let a = 5;		
    // let b = 7;
    // let c = a + b;
    // alert (c); 	    // the answer is 12.
</script>

Or, simply use numbers with the + operator.

var result = 5 + 7;
alert (result);	    

// Using ES6 features.
// let result = 5 + 7;
// alert (result);	    // its 12 again.

Note: The + operator can also be used to concatenate (or add) strings. I have explained about it here.

Its basic math and we have done this before. Therefore, lets begin with the Arithmetic Operators.

JavaScript Arithmetic Operators

Using + Operator to Concatenate Values

The + (plus) operator is often used to add two or more numbers. However, it can also be used to concatenate two values of different data types. For example,

var name = 'alpha';
var age = 27;
alert (name + ' is ' + age + ' years old');

// Using ES6
let name = 'alpha';
let age = 27;
alert (name + ' is ' + age + ' years old');

We can use the + on different "data types" to get different results. For example,

// Concatenating two string values.	
let a = 'arun ', b = 'banik';
alert (a + b);	 // the result is arun banik	

// or 

// Concatenating a string with number.
let x = 3, y = ' dimension';
alert (x + y); 	    // the result is 3 dimension.

Interesting isn't?

Note: Be careful while using the + operator. The results can vary.
Can you spot the difference between the two examples below?

1)
let a, b;
a = 5;
b = 7;
document.getElementById('result').innerHTML = 'a + b ' + ' = ' + (a + b);	

2)
let a, b;
a = 5;
b = 7;
document.getElementById('result').innerHTML = 'a + b ' + ' = ' + a + b;

Ok, let’s move on to the next set of operators.

JavaScript Comparison Operators

Comparison operators in JavaScript are used to compare two given values, and the result is returned in a Boolean value, that is, true or false.

JavaScript Conditional Operator

JavaScript also has a conditional operator called the ternary operator. It assigns a value to a varible after satisfying a conditon. Its actually works like the if...else statement. I have explained about ternary operator in detail here.

Syntax

Condition ? first_expression : second_expression

JavaScript Logical Operators

The logical operators are used to compare two or more conditions.

🚀 Learn more about Nullish coalescing operator (??)

JavaScript Assignment Operators

Assignment operators in JavaScript are used to assign values to variables. For example,

let a = 5;

Here, I have assigned the value 5 to the variable a using the = (or, equal assignment) operator. It can also be a = b, assigning value to a variable from another variable. There are many more assignment operators like this.

← PreviousNext →