JavaScript Number.isInteger() Method

In JavaScript, the Number.isInteger() is used to check the specified value for a parameter of this method is an integer value or not.

Here, Integer values mean the whole number that doesn’t contain the values after the decimal point, which could be a positive or negative integer.

Syntax

let num = 10l;
Number.isInteger(num);

Parameters

Returns

It returns true or false Boolean values based on whether the number is an integer or non-integer.

Example Codes

Pass Various Input Values for Number.isInteger()

In JavaScript, there are two types of numerical values. One is the whole number, which means an integer, and another is a float number, which means non-integers.

In a code snippet below, we will take the different numeric values and observe the output we get from the Number.isInteger() method.

let value1 = 10.2;
let value2 = 10;
let value3 = 0;

console.log(Number.isInteger(value1));
console.log(Number.isInteger(value2));
console.log(Number.isInteger(value3));

Output:

false
true
true

Use the Number.isInteger() Method With if-else Block

The following code example uses the if-else block with the Number.isInteger() method. We have taken two numbers and will check if both numbers are integers.

Then, we will multiply both input values if they are integers; otherwise, inform the user that the given numbers are not integers. It is a simple demonstration of how users can use the Number.isInteger() method in real-world programming.

See the following code.

let num1 = 0.2;
let num22 = 2;

if(Number.isInteger(num1) && Number.isInteger(num2)){
    console.log("Multiplication of Integers is " + num1*num2);
}else{
    console.log("Both numbers are not Integers.");
}

Output:

Both numbers are not Integers.