How to Check if a Variable or Number is Integer in JavaScript?

How to check if a variable or number is an integer in JavaScript?

In this article, we will provide different solutions on how to check if a variable or number is an integer.

Aside from that, you’ll learn about integers, how they differ from floats, and discover multiple methods to determine if a number in JavaScript is an integer.

What is Integer?

An integer is a type of number that doesn’t have a decimal component.

It is a whole number, which means it can be written without a fractional or decimal component.

For instance, numbers like 8, -5, and 0 are integers. They are often used in programming when you’re counting things that can’t be split up, like the number of people in a room.

How to check if number is integer JavaScript?

Here are a few ways to check if a number is an integer in JavaScript

Solution 1: Use the Number.isInteger() method

The Number.isInteger() method is the most straightforward way. The isInteger() method help us figure out if a number is an integer or not.

Here’s how it works:

You give this method a number, and it will check if the number is an integer.

If the number is an integer, the method will return true. If the number is not an integer (for instance, if it’s a decimal or a fraction), the method will return false.

Here’s an example code:

let sampleNumber = 16;
console.log(Number.isInteger(sampleNumber)); 

In our given example, 16 is an integer, so Number.isInteger(16) returns:

true

This method is really handy when you’re writing code and you need to make sure a number is an integer before you do something with it.

Solution 2: Use the typeof operator and the % operator

You can also use the typeof operator to check if the value is a number, and then use the modulus % operator to check if there is a remainder when divided by 1.

If there is no remainder, it means the number is an integer:

Here’s an example code:

let sampleNumber = 16;
console.log(typeof sampleNumber === 'number' && sampleNumber % 1 === 0);

Output:

true

Solution 3: Use Math.floor() or Math.ceil() or Math.round()

The Math.floor() or Math.ceil() or Math.round() are methods that are used to round a number down, up, or to the nearest integer respectively.

If the original number and the rounded number are the same, then it’s an integer.

Here’s an example:

let SampelNumber = 16;
console.log(SampelNumber === Math.floor(SampelNumber)); 

Output:

true

📌 Please keep in mind that each of these methods has its own use cases and limitations, so choose the one that best fits your needs.

What is the difference between integer and float?

An integer is a type of number that doesn’t have a decimal component. It’s a whole number, which means it can be written without a fractional or decimal component.

For example, numbers like 8, -5, and 0 are integers. They are often used in programming when you’re counting things that can’t be split up, like the number of people in a room.

On the other hand, float is a number that does have a decimal component. It’s short for “floating point number.”

This type of number can represent values that aren’t whole, like 3.14 or -0.12345. You’d use floats in programming when you need to represent values that can be fractional, like measurements or percentages.

So the main difference between an integer and a float is whether or not they can represent numbers with fractions or decimals.

If you’re dealing with whole numbers, you’d use an integer. But if you need to represent a number that isn’t whole, you’d use a float.

Conclusion

To sum up, we have provided several methods to check if a number is an integer.

The Number.isInteger() method is the most straightforward, but the typeof operator and the modulus % operator can also be used for this purpose.

Additionally, the Math.floor(), Math.ceil(), and Math.round() methods can be used to check if a number is an integer by comparing the original number with its rounded version.

Understanding the difference between integers and floats is important in programming, as it affects how numbers are represented and manipulated.

We hope this article has provided you with enough information to understand how to check if number is integer in JavaScript.

If you want to explore more JavaScript topics, check out the following articles:

• Array equality JavaScript
• JavaScript append to object
• Age calculator in JavaScript

Thank you for reading Itsourcecoders 😊.

Caren Bautista

Technical Writer at PIES IT Solution

Responsible for crafting clear, well-structured, and beginner-friendly content across the platform. Handles the writing, proofreading, and editorial review of tutorials, guides, and documentation to ensure every article is accurate, readable, and easy to follow.

Expertise: Technical Writing · Content Creation · Documentation · Editorial Writing · JavaScript · TypeScript · Python · Python Errors · HTTP Errors · MS Excel  · View all posts by Caren Bautista →