Web/JavaScript/Reference/Global objects/Number/isFinite

The Number.isFinite() method determines whether the passed value is a finite number — that is, it checks that a number is neither positive nor negative Infinity, since JavaScript has both.

Syntax

Number.isFinite(value)

Parameters

value: The value to be tested for finiteness.

Return value

A Boolean indicating whether or not the given value is a finite number.

Description

In comparison to the global isFinite() function, this method doesn't first convert the parameter to a number. This means only values of the type number and are finite return true.

Examples

Using isFinite

Number.isFinite(Infinity);  // false
Number.isFinite(NaN);       // false
Number.isFinite(-Infinity); // false

Number.isFinite(0);         // true
Number.isFinite(2e64);      // true

Number.isFinite('0');       // false, would've been true with
                            // global isFinite('0')
Number.isFinite(null);      // false, would've been true with
                            // global isFinite(null)

Polyfill

if (Number.isFinite === undefined) Number.isFinite = function(value) {
    return typeof value === 'number' && isFinite(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
`isFinite`	Chrome Full support 19	Edge Full support 12	Firefox Full support 16	IE No support No	Opera Full support 15	Safari Full support 9	WebView Android Full support ≤37	Chrome Android Full support 25	Firefox Android Full support 16	Opera Android Full support 14	Safari iOS Full support 9	Samsung Internet Android Full support 1.5	nodejs Full support 0.10

Legend

Full support: Full support
No support: No support