You are given the `root` of a binary search tree (BST) and an integer `val`.

Find the node in the BST that the node’s value equals `val` and return the subtree rooted with that node. If such a node does not exist, return `null`.

Example 1:

```Input: root = [4,2,7,1,3], val = 2
Output: [2,1,3]
```

Example 2:

```Input: root = [4,2,7,1,3], val = 5
Output: []
```

Constraints:

• The number of nodes in the tree is in the range `[1, 5000]`.
• `1 <= Node.val <= 107`
• `root` is a binary search tree.
• `1 <= val <= 107`

Solution:

``````/**
* Definition for a binary tree node.
* function TreeNode(val, left, right) {
*     this.val = (val===undefined ? 0 : val)
*     this.left = (left===undefined ? null : left)
*     this.right = (right===undefined ? null : right)
* }
*/
/**
* @param {TreeNode} root
* @param {number} val
* @return {TreeNode}
*/
var searchBST = function(root, val) {
if (root === null) return null
if (root.val === val)
return root;
else if (val < root.val)
return searchBST(root.left, val);
else
return searchBST(root.right, val);
};``````