// https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/add-a-new-element-to-a-binary-search-tree

var displayTree = (tree) => console.log(JSON.stringify(tree, null, 2));
function Node(value) {
  this.value = value;
  this.left = null;
  this.right = null;
}
function BinarySearchTree() {
  this.root = null;
  // Only change code below this line
  this.add = (item) => {
    const newNode = new Node(item);
    if (this.root === null) {
      this.root = newNode;
    }
    let parentNode = null;
    let nodeBranch = "left";
    let node = this.root;
    while (node !== null) {
      parentNode = node;
      if (node.value == item) {
        return null;
      } else if (node.value < item) {
        nodeBranch = "right";
        node = node.right;
      } else {
        nodeBranch = "left";
        node = node.left;
      }
    }
    parentNode[nodeBranch] = newNode;
  };
  // Only change code above this line
}