Difference Between == & === in JavaScript

In Javascript, equality operators like double equals (==) and triple equals (===) are used to compare two values. But both operators do different jobs. Double equals (==) will try to convert the values to the same data type and then try to compare them. But triple equals (===) strictly compares the value and the datatype.

Two Types

• Double equality (==)
• Triple equality (===)

Example 1: Double Equality (==)

In this example, we are trying to compare a string and a number.

• Assigning the value “10” to a variable called string.
• Assigning the value 10 to a variable called number.
• The third statement compares the string and number and prints the result on the console. Here we are using double equals (==) so it checks the inner value rather than the datatype.

Javascript

let string = "10";
let number = 10;

console.log(string == number);

Output

true

The output is true, because they have different data type but same value.

Example 2: Triple Equality (===)

In this example, we are trying to compare a string and a number.

• Assigning the value “20” to a variable called string.
• Assigning the value 20 to a variable called a number.
• The third statement compares the string and number and prints the result on the console. Here we are using triple equals (===) so it checks the inner value and the datatype.

Javascript

let string = "20";
let number = 20;

console.log(string === num);

Output:

false