优化非尾递归函数

function factorial(n) {
  if (n === 0) {
    return 1;
  } else {
    return n * factorial(n - 1);
  }
}

function factorial(n) {
  let result = 1;
  for (let i = 1; i <= n; i++) {
    result *= i;
  }
  return result;
}

function factorial(n, acc = 1) {
  if (n === 0) {
    return acc;
  } else {
    return factorial(n - 1, acc * n);
  }
}

function factorial(n, acc = 1) {
  if (n === 0) {
    return acc;
  } else {
    return factorial(n - 1, acc * n);
  }
}