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

console.log(Number.isFinite(1 / 0));
// Expected output: false

console.log(Number.isFinite(10 / 5));
// Expected output: true

console.log(Number.isFinite(0 / 0));
// Expected output: false

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.

Examples

Using isFinite()

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.

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

Specifications

Browser compatibility

See also

• Polyfill of Number.isFinite in core-js
• es-shims polyfill of Number.isFinite
• Number
• isFinite()