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
.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
The source for this interactive example is stored in a GitHub
repository. If you'd like to contribute to the interactive examples project, please
clone https://github.com/mdn/interactive-examples
and send us a pull request.
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
Browser compatibility
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