BinarySearchTree.js

function Node(data, left, right) {
  this.data = data;
  this.left = left;
  this.right = right;
  this.show = show;
}

function show() {
  return this.data;
}

function BinarySearchTree() {
  this.root = null;
  this.insert = insert;
  this.inOrder = inOrder;
  this.preOrder = preOrder;
  this.postOrder = postOrder;
  this.getMin = getMin;
  this.getMax = getMax;
  this.find = find;
  this.remove = remove;
}

// insert
function insert(data) {
  var n = new Node(data, null, null);

  if (this.root == null) {
    this.root = n;
  } else {
    var current = this.root;
    var parent;
    while (true) {
      parent = current;
      if (data < current.data) {
        current = current.left;
        if (current == null) {
          parent.left = n;
          break;
        }
      } else {
        current = current.right;
        if (current == null) {
          parent.right = n;
          break;
        }
      }
    }
  }
}

// traverse
function inOrder(node) {
  if (!(node == null)) {
    inOrder(node.left);
    node.show();
    inOrder(node.right);
  }
}

function preOrder(node) {
  if (!(node == null)) {
    node.show();
    preOrder(node.left);
    preOrder(node.right);
  }
}

function postOrder(node) {
  if (!(node == null)) {
    postOrder(node.left);
    postOrder(node.right);
    node.show();
  }
}

// Search

function getMin() {
  var current = this.root;
  while (!(current.left == null)) {
    current = current.left;
  }
  return current.data;
}

function getMax() {
  var current = this.root;
  while (!(current.right == null)) {
    current = current.right;
  }
  return current.data;
}

function find(data) {
  var current = this.root;
  while (current.data != data) {
    if (data < current.data) {
      current = current.left;
    } else {
      current = current.right;
    }
    if (current == null) {
      return null;
    }
  }
  return current;
}

// remove
// Receive the value to be remove.
function remove(data) {
  root = removeNode(this.root, data);
}

// Main function
function removeNode(node, data) {
  if (node == null) {
    return null;
  }
  if (data == node.data) {
    // node has no children
    if (node.left == null && node.right == null) {
      return null;
    }
    // node has no left child
    if (node.left == null) {
      return node.right;
    }
    // node has no right child
    if (node.right == null) {
      return node.left;
    }
    // node has two children
    var tempNode = getSmallest(node.right);
    node.data = tempNode.data;
    node.right = removeNode(node.right, tempNode.data);
    return node;
  } else if (data < node.data) {
    node.left = removeNode(node.left, data);
    return node;
  } else {
    node.right = removeNode(node.right, data);
    return node;
  }
}