What is the difference between "==" and "==="?

October 1, 2022

What is the difference between “==” and “===”?

The fundamental difference between the == and === operators in JavaScript is that the == operator compares the operand’s types before comparing them, whereas the === operator compares the operand’s values as well as their data type.

Double Equals for Equality

== operator is used for comparison between two variables irrespective of their data type.

Triple Equals for Identity

=== operator is used for comparison between two variables but this will have a strict type check, which means it will check data type and compare both the values of the variables.

Test Cases

Double Equals:

var num1 = 5;
var num2 = 5;
console.log(num1 == num2); //true

Triple Equals
var num1 = 5;
var num2 = 5;
console.log(num1 === num2); //true

Double Equals

var num1 = 5;
var num2 = 5.0;
console.log(num1 == num2); //true

Triple Equals

var num1 = 5;
var num2 = 5.0;
console.log(num1 === num2); //true

Double Equals

var num1 = "5";
var num2 = "5.0";
console.log(num1 == num2); //false  Because "5" is string

Triple Equals

var num1 = "5";
var num2 = "5.0";
console.log(num1 === num2); //false  Because "5" is string

Double Equals

var num1 = [];
var num2 = [];
console.log(num1 == num2); //false  Because comparing arrays

Triple Equals

var num1 = [];
var num2 = [];
console.log(num1 === num2); //false  Because comparing arrays

Double Equals

var num1 = {};
var num2 = {};
console.log(num1 == num2); //false  Because comparing object

Triple Equals

var num1 = {};
var num2 = {};
console.log(num1 === num2); //false  Because comparing object

JavaScript Code:

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <title>Difference between Double & Triple Equal</title>
</head>

<body>
    <script>
        var num1 = 5;
        var num2 = 5;
        console.log(num1 == num2); //true

        var num1 = 5;
        var num2 = 5.0;
        console.log(num1 === num2); //true

        var num1 = "5";
        var num2 = "5.0";
        console.log(num1 === num2); //false  Because "5" is string

        var num1 = [];
        var num2 = [];
        console.log(num1 === num2); //false  Because comparing arrays

        var num1 = {};
        var num2 = {};
        console.log(num1 === num2); //false  Because comparing object

    </script>
</body>
</html>