sortedArrayToBST = (nums, left = 0, right = (nums.length - 1)) => {
    const isBaseCase = (right < left);
    if (isBaseCase) return null;

    return dfs(nums, left, right);/* Time O(N) | Space O(log(N)) */
}
DFS - Preorder | Left as mid
Time O(N) | Space O(log(N))
https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/
@param {number[]} nums
@return {TreeNode}