Web/JavaScript/Reference/Global objects/Number/isInteger

The Number.isInteger() method determines whether the passed value is an integer.

Syntax

Number.isInteger(value)

Parameters

value: The value to be tested for being an integer.

Return value

A Boolean indicating whether or not the given value is an integer.

Description

If the target value is an integer, return true, otherwise return false. If the value is NaN or Infinity, return false. The method will also return true for floating point numbers that can be represented as integer.

Examples

Using isInteger

Number.isInteger(0);         // true
Number.isInteger(1);         // true
Number.isInteger(-100000);   // true
Number.isInteger(99999999999999999999999); // true

Number.isInteger(0.1);       // false
Number.isInteger(Math.PI);   // false

Number.isInteger(NaN);       // false
Number.isInteger(Infinity);  // false
Number.isInteger(-Infinity); // false
Number.isInteger('10');      // false
Number.isInteger(true);      // false
Number.isInteger(false);     // false
Number.isInteger([1]);       // false

Number.isInteger(5.0);       // true
Number.isInteger(5.000000000000001); // false
Number.isInteger(5.0000000000000001); // true

Polyfill

Number.isInteger = Number.isInteger || function(value) {
  return typeof value === 'number' && 
    isFinite(value) && 
    Math.floor(value) === value;
};

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'Number.isInteger' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`isInteger`	Chrome Full support 34	Edge Full support 12	Firefox Full support 16	IE No support No	Opera Full support 21	Safari Full support 9	WebView Android Full support ≤37	Chrome Android Full support 34	Firefox Android Full support 16	Opera Android Full support 21	Safari iOS Full support 9	Samsung Internet Android Full support 2.0	nodejs Full support 0.12

Legend

Full support: Full support
No support: No support