javascript中实现的链表

function Entry(next, data)
{
       this.next = next
       this.data = data
}

function Iterator(node)
{
       this.cousor = node
       this.hasNext = function ()
       {
               return (this.cousor.next != null);
       }
       this.next = function ()
       {
               var rt = this.cousor.next
               this.cousor = this.cousor.next
               return rt.data
       }
}

function LinkedList()
{
       this.head = new Entry(null, null)
       this.size = function ()
       {
               var size = 0
               if (this.head == null)
               {
                       return size
               }

               var p = this.head.next
               for(; p!=null; p = p.next)
               size++;
               return size;
       }

       this.clear = function ()
       {
               this.head = null
       }

       this.getNode =  function (idx)
       {
               var pos = -1;
               var p = this.head
               while (p != null && pos < idx) {
                       p = p.next;
                       pos ++;
               }
               return p;
       }

       this.get = function (idx)
       {
               return this.getNode(idx).data
       }

       this.add = function (data)
       {
               this.insert(this.size(), data)
       }

       this.insert = function (idx, data)
       {
               var p = this.getNode(idx-1); /**//*注意查询idx-1*/
               
               if (p == null){
                       return
               }
               var node = new Entry(p.next, data)
               p.next = node
       }

       this.remove = function (idx)
       {
               var prenode = this.getNode(idx - 1)
               var node = this.getNode(idx)
               if (prenode == null || node == null)
               {
                       return null
               }
               prenode.next = node.next
               return node.data
       }

       this.iterator = function ()
       {
               return new Iterator(this.head)
       }

       this.swap = function (a, b)
       {
               var av = this.getNode(a)
               var bv = this.getNode(b)
               var tmp = av.data
               av.data = bv.data
               bv.data = tmp
       }
}