Data Structures: Add a New Element to a Binary Search Tree: The method should be called addand it should accept an integer value to add to the tree. Take care to maintain the invariant of a binary search tree: the value in each left child should be less than or equal to the parent value, and the value in each right child should be greater than o…

addNodeToBinarySearchTree.js

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;
 
  this.add = function(val) {
      let newNode = new Node(val);
      let currentNode = this.root;
      if(!currentNode){
          this.root = newNode;
          return;
      }else{
          let searchTree = function(currentNode) {
              if(val < currentNode.value){
                  if(currentNode.left){
                      searchTree(currentNode.left);
                  }else{
                      currentNode.left = newNode;
                      return;
                  }
              }else if(val > currentNode.value){
                  if(currentNode.right){
                      searchTree(currentNode.right);
                  }else{
                      currentNode.right = newNode;
                      return;
                  }
              }else{
                  return null;
              }
          };
          searchTree(currentNode);
      }
  };
}