factorial javascript function

1function factorial(n) {
2  if (n < 0) return;
3  if (n < 2) return 1;
4  return n * factorial(n - 1);
5}

1function factorialize(num) {
2  var result = num;
3  if (num === 0 || num === 1) 
4    return 1; 
5  while (num > 1) { 
6    num--;
7    result *= num;
8  }
9  return result;
10}

1    function factorial(n) {
2        if (n > 1) {
3            return n * factorial(n - 1);
4        }
5        return 1;
6    }

1function factorialize(num) {
2  if (num < 0) 
3        return -1;
4  else if (num == 0) 
5      return 1;
6  else {
7      return (num * factorialize(num - 1));
8  }
9}
10factorialize(5);

1function factorialize(num) {
2  if(num < 2) return 1;
3  return num *= factorialize(num - 1);
4}