Number.isFinite()

The Number.isFinite() method determines whether the passed value is a finite number.

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 forcibly convert the parameter to a number. This means only values of the type number, that are also finite, return true.

Examples

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

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
isFiniteChrome Full support 19Edge Full support 12Firefox Full support 16IE No support NoOpera Full support 15Safari Full support 9WebView Android Full support YesChrome Android Full support 25Firefox Android Full support 16Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yesnodejs Full support 0.10

Legend

Full support  
Full support
No support  
No support

See also

Related Topics
  1. Standard built-in objects
  2. Number
  3. Properties
    1. Number.EPSILON
    2. Number.MAX_SAFE_INTEGER
    3. Number.MAX_VALUE
    4. Number.MIN_SAFE_INTEGER
    5. Number.MIN_VALUE
    6. Number.NEGATIVE_INFINITY
    7. Number.NaN
    8. Number.POSITIVE_INFINITY
    9. Number.prototype
  4. Methods
    1. Number.isFinite()
    2. Number.isInteger()
    3. Number.isNaN()
    4. Number.isSafeInteger()
    5. Number.parseFloat()
    6. Number.parseInt()
    7. Number.prototype.toExponential()
    8. Number.prototype.toFixed()
    9. Number.prototype.toLocaleString()
    10. Number.prototype.toPrecision()
    11. Number.prototype.toSource()
    12. Number.prototype.toString()
    13. Number.prototype.valueOf()
    14. Number.toInteger()
  5. Inheritance:
  6. Function
  7. Properties
    1. Function.arguments
    2. Function.arity
    3. Function.caller
    4. Function.displayName
    5. Function.length
    6. Function.name
    7. Function.prototype
  8. Methods
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.isGenerator()
    5. Function.prototype.toSource()
    6. Function.prototype.toString()
  9. Object
  10. Properties
    1. Object.prototype.__count__
    2. Object.prototype.__noSuchMethod__
    3. Object.prototype.__parent__
    4. Object.prototype.__proto__
    5. Object.prototype.constructor
  11. Methods
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.unwatch()
    12. Object.prototype.valueOf()
    13. Object.prototype.watch()
    14. Object.setPrototypeOf()