how to calculate factorial in javascript 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: javascript factorial

function factorialize(num) {
  if (num === 0 || num === 1)
    return 1;
  for (var i = num - 1; i >= 1; i--) {
    num *= i;
  }
  return num;
}
factorialize(5);

Example 3: javascript factorial of a number

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

// Examples
factorial(2);   // 2
factorial(3);   // 6