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

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 Latest Draft (ECMA-262)
The definition of 'Number.isInteger' in that specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
isIntegerChrome Full support 34Edge Full support 12Firefox Full support 16IE No support NoOpera Full support 21Safari Full support 9WebView Android Full support ≤37Chrome Android Full support 34Firefox Android Full support 16Opera Android Full support 21Safari iOS Full support 9Samsung Internet Android Full support 2.0nodejs Full support 0.12

Legend

Full support  
Full support
No support  
No support

See also

  • The Number object it belongs to.