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 infinite, return false.

Examples

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

Polyfill

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

Specifications

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Number.isInteger' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'Number.isInteger' in that specification.	Draft

Browser compatibility

See also

• The Number object it belongs to.