701-Insert-into-a-Binary-Search-Tree.js

// 701. Insert into a Binary Search Tree [Medium]
// https://leetcode.com/problems/insert-into-a-binary-search-tree/

/* eslint-disable no-param-reassign */
/**
 * 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}
 */
const insertIntoBST = (root, val) => {
  // eslint-disable-next-line no-undef
  if (!root) return new TreeNode(val);

  if (val >= root.val) {
    root.right = insertIntoBST(root.right, val);
  } else {
    root.left = insertIntoBST(root.left, val);
  }

  return root;
};