How to check if a variable is an integer in JavaScript

How 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.

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 theNumber class, it returns false.

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

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

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

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

See recent articles by JS Nooby

FEATURED

How to Insert an element before another DOM element with JavaScript

Insert an element before another DOM element with JavaScript

FEATURED

How to trigger built-in and custom events using JavaScript

Triggering built-in and custom events using JavaScript

FEATURED

How to remove an event handler in JavaScript

How to remove an event handler in JavaScript

FEATURED

Introduction to Service Workers in JavaScript

Introduction to Service Workers in JavaScript

FEATURED

How to use object & array destructuring in JavaScript

How to use object & array destructuring in JavaScript

FEATURED

How to check if an object is an array in JavaScript

How to check if an object is an array in JavaScript