.isFinite()

Published Oct 12, 2021Updated Oct 13, 2021
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The .isFinite() method is a part of the Number class in JavaScript.

It accepts a single argument, value, returns true if the passed argument is a finite number, and returns false if the passed argument is either positive Infinity, negative Infinity, or NaN.

Syntax

Number.isFinite(value);
  • value (required): The value to check.

Examples

To verify if a value is a finite number or not:

const x = 1 / 0;
// x = Infinity
console.log(Number.isFinite(x));
// Output: false
const y = 0 / 0;
// y = NaN
console.log(Number.isFinite(y));
// Output: false
const z = 10 / 5;
// z = 2
console.log(Number.isFinite(z));
// Output: true

The above example passes an Infinity, a NaN, and an integer value, into the Number.isFinite() method to verify if each value is finite or not. The result is then printed.

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