# How to check if a variable is an integer in JavaScript

By Atta Ur Rehman Shah (https://attacomsian.com/about). Published Sep 17, 2022. Topics: JavaScript.
Canonical URL: https://attacomsian.com/blog/javascript-check-if-variable-is-integer

> Learn how to use the Number.isInteger() method to check if a variable is an integer in JavaScript.

To check if a variable is an integer in JavaScript, use the `Number.isInteger()` method. It returns `true` if the given value is an integer. Otherwise, `false`.

```javascript
Number.isInteger(34)         // true
Number.isInteger(2e64)       // true

Number.isInteger('0')        // false
Number.isInteger(Math.PI)    // false
Number.isInteger(null)       // false
Number.isInteger({})         // false

Number.isInteger(Infinity)   // false
Number.isInteger(NaN)        // false
Number.isInteger(-Infinity)  // false
```

The `Number.isInteger()` method was introduced in ES6 to determine whether the passed value is an integer.

If the given value is an integer, it returns `true`. For non-numeric values, `NaN`, positive or negative `Infinity`, or even for an instance of the`Number` class, it returns `false`. 

The `Number.isInteger()` method will also return `true` for floating point numbers that can be represented as an integer:

```javascript
Number.isInteger(2.0)                  // true
Number.isInteger(2.3)                  // false
Number.isInteger(new Number(2))        // false
```