Number.isFinite()

The Number.isFinite() method determines whether the passed value is a finite number — that is, it checks that the type of a given value is Number, and the number is neither positive Infinity, negative Infinity, nor NaN.

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Syntax

Number.isFinite(value)

Parameters

value

The value to be tested for finiteness.

Return value

The boolean value true if the given value is a finite number. Otherwise false.

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 Language Specification
# sec-number.isfinite

Browser compatibility

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See also