how to implement ! factorial in js code example

Example 1: javascript factorial

function factorial(n) {
  if (n < 0) return;
  if (n < 2) return 1;
  return n * factorial(n - 1);
}

Example 2: factorial javascript

// Simple arrow function solution
var factorial = n => (n <= 0) ? 1: n * factorial(n - 1);