为什么着这个所有的key会报错？未定义。

function BinaryTree(){

var Node = function(){

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){

node.left = newNode;

}else{

insertNode(node.left, newNode);

}

}else{

if(node.rigth === null){

node.rigth = newNode;

}else{

insertNode(node.rigth, newNode);

}

}

}

this.insert = function(key){

var newNode = new Node(key);

if(root === null){

root = node;

}else{

insertNode(root, newNode);

}

}

}

var nodes = [8, 3, 10, 1, 6, 14, 4, 7, 13];

var binaryTree = new BinaryTree();

nodes.forEach(function(key){

binaryTree.insert(key);

});