JavaScript 实现二叉树

JavaScript 实现二叉树：

// JavaScript 实现二叉树

function BinaryTree ()
{
  var Node = function (key)
  {
    this.key = key;
    this.left = null;
    this.right = null;
  }

  var root = null;

  var insertNode = function (Node, newNode)
  {
    if (newNode.key < node.key) {
      if (node.left === null) {
        if (node.left === null) {
          node.left = newNode;
        } else {
          insertNode(node.left, newNode);
        }
      } else {
        if (node.right === null) {
          node.right = newNode;
        } else {
          insertNode(node.left, newNode);
        }
      } else {
        if (node.right === null) {
          node.right = newNode;
        } else {
          insertNode(node.right, newNode);
        }
      }
    }

    this.insert = function (key)
    {
      var newNode = new Node(key);
      if (root === null) {
        root = node;
      } else {
        insertNode(root, newNode);
      }
    }

    // 中序遍历
    var inOrderTraverseNode = function (node, callback)
    {
      if (node !== null) {
        inOrderTraverseNode(node.left, callback);
        callback(node.key);
        inOrderTraverseNode(node.right, callback);
      }
    }

    this.inOrderTraverse = function (callback)
    {
      inOrderTraverseNode(root, callback);
    }
  }
}

var nodes = [8, 3, 10, 1, 6, 14, 4, 7, 13];
var binaryTree = new BinaryTree();
nodes.forEach (function (key))
{
  binaryTree.insert(key);
}

var callback = function (key)
{
  console.log(key);
}

binaryTree.inOrderTraverse(callback);