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

Number.isFinite = 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 2017 Draft (ECMA-262) The definition of 'Number.isInteger' in that specification.	Draft

Browser compatibility

See also

• The Number object it belongs to.