Factorial function

Javascript example of factorial function without side effect.

by Dmytro Chumak

HTML

<a href="https://www.mathsisfun.com/numbers/factorial.html" target="_blank" rel="noreferrer noopener">Link</a> to factorial theory.

JavaScript

function factorial(n) {
	if (n === 0) return 1;
	return n * factorial(n - 1);
}

alert(factorial(3) === 6 && factorial(0) === 1);