factorial

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. Throws an exception if n is a negative number.

typescript

const factorial = (n: number): number => (n <= 1 ? 1 : n * factorial(n - 1));

typescript

factorial(6); // 720