Factorial.js

// In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. For example: 5! = 5 * 4 * 3 * 2 * 1 = 120. By convention the value of 0! is 1.

// Write a function to calculate factorial for a given input. If input is below 0 or above 12 throw an exception of type ArgumentOutOfRangeException (C#) or IllegalArgumentException (Java) or RangeException (PHP) or throw a RangeError (JavaScript) or ValueError (Python) or return -1 (C).

// More details about factorial can be found here.

function factorial(n) {
  if (n == 0) return 1
  if (n > 12) throw RangeError
  return factorial(n - 1) * n
}

console.log(factorial(0), 1, 'factorial for 0 is 1')
console.log(factorial(1), 1, 'factorial for 1 is 1')
console.log(factorial(2), 2, 'factorial for 2 is 2')
console.log(factorial(3), 6, 'factorial for 3 is 6')