Partial Binary Search Tree and Node implementation

partialbinarysearchtree.js

/**
* Partial Binary Search Tree class.
* @author Bijan Vakili
*/
var Node = function() {

    // Private variable to access 'this' context from privileged method
    var that = this;

    // Public variables
    this.left = null; // Node
    this.right = null; // Node
    this.value = null; // int

    // Public/priveleged method
    this.height = function() {
        
        // include current node in calculation
        var leftHeight = 1;
        var rightHeight = 1;

        // recursively get the height of left tree
        if (that.left) {
            leftHeight += that.left.height();
        }

        // recursively get the height of right tree
        if (that.right) {
            rightHeight += that.right.height();
        }

        // get the maximum of the left or right
        var thisHeight = Math.max(leftHeight, rightHeight);

        // if no left or right then do not count this
        // all initialized nodes would left/right
        if (!that.right && !that.left) {
            thisHeight = 0;
        }

        return thisHeight;
    }
}

var BST = function () {

    // Private variables
    // declare and initialize the root node
    var root = new Node(); // Node

    // Private method
    var insert = function(value, parent) {
        // if the parent has not be initialized, initialize it
        // this would be the case for the root element on first run
        if (parent.value === null) {
            parent.value = value;
            parent.left = new Node();
            parent.right = new Node();
            return true;
        }

        // if the value is greater, add to the right, otherwise if less, left
        if (value > parent.value) {
            insert(value, parent.right);
        } else if (value < parent.value) {
            insert(value, parent.left);
        } else {
            // Do nothing as BST is a set
            // A set need not have duplicate values
        }

        return true;
    }

    // Public methods
    this.add = function(value) {
        // call the private method
        insert(value, root);
    }
    // get the root node's height
    this.height = function() {
        return root.height();
    }
}


/** Begin Test **/
$(document).ready(function() {


    // Print function for test
    var resultQuestion3 = $("#result-question3");
    function logIt(x) {
        resultQuestion3.append(x + "<br />")
        console.log(x);
    }

    /**
           5
        3     12
       2 4   9  22
              15   55
                 28  66
    **/
    var data = "5,3,4,2,12,22,55,66,15,28,9";
    var dataArray = data.split(",");
    var tree = new BST();
    for (dataEntry of dataArray) {  
        tree.add(dataEntry);
    }
    logIt("");
    logIt("Test 1:");
    logIt("Entries: " + dataArray);
    logIt("Height : " + tree.height());

    var tree2 = new BST();
    dataArray = [1];
    tree2.add(dataArray[0]);
    logIt("");
    logIt("Test 2:");
    logIt("Entries: " + dataArray);
    logIt("Height : " + tree2.height());


    var tree3 = new BST();
    dataArray = [];
    for (var i = 0; i < 8; i++) {
        tree3.add(i);
        dataArray.push(i);
    }
    logIt("");
    logIt("Test 3:");
    logIt("Entries: " + dataArray);
    logIt("Height : " + tree3.height());

    var tree4 = new BST();
    dataArray = [];
    for (var i = 0; i > -7; i--) {
        tree4.add(i);
        dataArray.push(i);
    }
    logIt("");
    logIt("Test 4:");
    logIt("Entries: " + dataArray);
    logIt("Height : " + tree4.height());

});