Number.isFinite()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

Try it

Syntax

js
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.

Examples

Using isFinite()

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

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

Difference between Number.isFinite() and global isFinite()

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, and non-numbers always return false.

js
isFinite("0"); // true; coerced to number 0
Number.isFinite("0"); // false
isFinite(null); // true; coerced to number 0
Number.isFinite(null); // false

Specifications

Specification
ECMAScript Language Specification
# sec-number.isfinite

Browser compatibility

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See also