freeCodeCamp/guide/english/javascript/standard-objects/number/number-isinteger/index.md

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Number isInteger

Number isInteger

Description

The Number.isInteger() method determines whether the passed value is an integer. This method was introduced in ES6

Syntax

Number.isInteger(val)

Parameters

val - value to check for being an integer

Return value

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

Description

The method returns true if passed value is an integer, otherwise it returns false. Infinite and NaN values return false.

Examples

Number.isInteger(0);         // true
Number.isInteger(-0);        // true
Number.isInteger(1);         // true
Number.isInteger(2);         // true
Number.isInteger(-100001);   // true
Number.isInteger(999999999999999999999999); // true

Number.isInteger(0.1);       // false
Number.isInteger(0.3);       // 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

More Information:

ECMA 2015 Docs
Number.isInteger() MDN Web Docs