implimentation of a linklist

linkListImpliment

LinkedList.Circular = function() {};
LinkedList.Circular.prototype = new LinkedList();
LinkedList.Circular.prototype.append = function(node) {
  if (this.first === null) {
    node.prev = node;
    node.next = node;
    this.first = node;
    this.last = node;
  } else {
    node.prev = this.last;
    node.next = this.first;
    this.first.prev = node;
    this.last.next = node;
    this.last = node;
  }
  this.length++;
};
LinkedList.Circular.prototype.insertAfter = function(node, newNode) {
  newNode.prev = node;
  newNode.next = node.next;
  node.next.prev = newNode;
  node.next = newNode;
  if (newNode.prev == this.last) { this.last = newNode; }
  this.length++;
};
LinkedList.Circular.prototype.remove = function(node) {
  if (this.length > 1) {
    node.prev.next = node.next;
    node.next.prev = node.prev;
    if (node == this.first) { this.first = node.next; }
    if (node == this.last) { this.last = node.prev; }
  } else {
    this.first = null;
    this.last = null;
  }
  node.prev = null;
  node.next = null;
  this.length--;
};
LinkedList.Node = function(data) {
  this.prev = null; this.next = null;
  this.data = data;
};
// myList.append(new LinkedList.Node(someObject));