Arrayish Linked List in JavaScript

LinkedList.js

var LinkedList = function () {
  "use strict";
  
  var _this = this
    , first
    , last;

  /**
   * These hold data and link to the next node.
   * 
   * @param {Object} item Item being added to list.
   */
  var Node = function (item) {
    return {data: item, next: undefined};
  };
  
  /** 
   * Return node at index.
   * 
   * @param {Integer} ind Requested position in list
   * @return {Node} Node at requested position.
   */
  var getter = function atIndex (ind) {
    var buffer;
    
    for(var i = 0; i <= ind; i++) {
      buffer = buffer ? buffer.next : first;
    }
    
    return buffer;
  }
  
  // Holds the count of all currently linked nodes.
  getter.count = 0;
  
  /**
   * Add a node to the linked list
   * 
   * @param {Object} item Data to add to linked list as node.
   */
  getter.add = function (item) {
    var node = new Node(item);
    
    if(!first) first     = node;
    
    // The last node should link to this node.
    if(last)   last.next = node;
    
    // The final node in the list should link back to the first.
    node.next = first;
    last = node;
    this.count++;
  };
  
  /**
   * Remove last item from linked list
   * 
   * return {Object} last item that no longer exists in list.
   */
  getter.pop = function () {
    var previous
      , popped;
    
    if(this.count > 1) {
      previous = getter(this.count - 2);
      popped   = previous.next;
      
      // Remove pointer to last item so it can be garbage collected.
      previous.next = first;
      last = previous;
      this.count--;
    } else {
      first = undefined;
      last  = undefined;
      this.count = 0;
    }
      
    return popped;
  };
  
  /**
   * Remove all items from list (good for destroying data)
   */
  getter.empty = function () {
    for(var i = 0; i < this.count; i++) {
      this.pop();
    }
  };
  
  return getter;
};