deserialize = function(data) {
    const isBaseCase = !data.length;
    if (isBaseCase) return null;

    const val = data.shift();

    const isNull = val === null;
    if (isNull) return null;

    return dfsDeserialize(val, data)
}
Decodes your encoded data to tree.
https://leetcode.com/problems/serialize-and-deserialize-binary-tree/solution/
Time O(N) | Space O(H)
@param {string} data
@return {TreeNode}