const reverseIterative = (arr) => {
  const result = [];
  for (let i = arr.length - 1; i >= 0; i--) {
    result.push(arr[i]);
  }

  return result;
};

const reverseRec = (arr) =>
  arr.length === 0 ? [] : arr.slice(-1).concat(reverseRec(arr.slice(0, -1)));

// reverseRec([1, 2, 3]);
// [3] + reverseRec([1, 2])
// [3] + ([2] + reverseRec([1]))
// [3] + ([2] + ([1] + reverseRec([])))
// [3] + ([2] + ([1] + []))
// [3] + ([2] + [1])
// [3] + [2, 1]
// [3, 2, 1]