30-seconds-of-code/javascript/snippets/factorial.md

title, type, tags, cover, dateModified

title	type	tags	cover	dateModified
Factorial of number	snippet	math algorithm recursion	flower-vase	2020-12-28T13:49:24+02:00

Calculates the factorial of a number.

• Use recursion.
• If n is less than or equal to 1, return 1.
• Otherwise, return the product of n and the factorial of n - 1.
• Throw a TypeError if n is a negative number.

const factorial = n =>
  n < 0
    ? (() => {
        throw new TypeError('Negative numbers are not allowed!');
      })()
    : n <= 1
    ? 1
    : n * factorial(n - 1);

factorial(6); // 720