Linked lists in JS... Useful but only for very specific cases (they kick array's ass in prepending items, as expected)

linkedList.js

// LinkedListNode Class (Module pattern with cached functions)
!function(){
  LinkedListNode = function LinkedListNode(data) {
    this.node = [data, null];
  }

  LinkedListNode.prototype.getNext = getNext;
  LinkedListNode.prototype.getData = getData;
  LinkedListNode.prototype.setNext = setNext;
  LinkedListNode.prototype.setData = setData;

  function getNext() {
    return this.node[1];
  }

  function getData() {
    return this.node[0];
  }

  function setNext(node) {
    this.node[1] = node;
  }

  function setData(data) {
    this.node[0] = data;
  }
}()


// LinkedList Class (Module pattern with cached functions)
!function(){
  LinkedList = function LinkedList() {
    this.list = null;
    this.last = null;
  };

  LinkedList.prototype.print = print;
  LinkedList.prototype.append = append;
  LinkedList.prototype.prepend = prepend;
  LinkedList.prototype.remove = remove;
  LinkedList.prototype.removeLast = removeLast;

  function print() {
    if (this.list) {
      var current = this.list,
          result = '';
      while (current !== null) {
        result += ' ~> ' + current.getData();
        current = current.getNext();
      }
      console.log(result);
    }
  }

  function append(data) {
    var node = new LinkedListNode(data);

    if(this.last === null) {
      this.list = node;
    } else {
      this.last.setNext(node);
    }

    return this.last = node;
  }

  function prepend(data) {
    var node = new LinkedListNode(data);
    node.setNext(this.list);
    return this.list = node;
  }

  function remove(node) {
    if(typeof(node) === 'number') {
      // removing by position
      var prev = this.list,
          i = 0;

      for(; i < node - 1 && prev !== null; i++) {
        prev = prev.getNext();
      }

      if(prev !== null && prev.getNext() !== null) {
        prev.setNext(prev.getNext().getNext());
      }

    } else if(node instanceof LinkedListNode) {
      // removing a node
      var nxt = node.getNext();

      if(nxt !== null) {
        node.setData(nxt.getData());
        node.setNext(nxt.getNext());
      } else {
        this.removeLast();
      }

    } else {
      console.error('Invalid element to remove');
    }
  }

  function removeLast() {
    var target = this.list;
    if(target !== null) {
      if(target.getNext() === null) {
        this.list = null;
      } else {
        while(target.getNext().getNext() !== null) {
          target = target.getNext();
        }
        target.setNext(null);
      }
    }
  }
}()


// Testing it out!

function vageTest() {
  var list = new LinkedList();
  var toRemove = list.append('bar');
  list.append('baz');
  list.prepend('foo');
  list.append('another');
  list.append('removed');
  list.append('node');
  list.remove(toRemove);
  list.remove(3);
  list.removeLast();
  list.print();
}

function efficiencyTestPrepend(ELEMENTS) {
  var list = new LinkedList();
  var arr = new Array();
  var i, start, end, deltaArray, deltaList;
  ELEMENTS = ELEMENTS || 10000;

  // array case
  start = new Date();
  for (i = 0; i < ELEMENTS; i++) {
    arr.splice(0,0,i);
  }
  end = new Date();
  deltaArray = end.getTime() - start.getTime();

  // list case
  start = new Date();
  for (i = 0; i < ELEMENTS; i++) {
    list.prepend(i);
  }
  end = new Date();
  deltaList = end.getTime() - start.getTime();

  console.log('Efficiency Test: Prepend ' + ELEMENTS + ' items.');
  console.log('Array:\t\t' + deltaArray + 'ms');
  console.log('LinkedList:\t' + deltaList + 'ms');
}

function efficiencyTestAppend(ELEMENTS) {
  var list = new LinkedList();
  var arr = new Array();
  var i, start, end, deltaArray, deltaList;
  ELEMENTS = ELEMENTS || 10000;

  // array case
  start = new Date();
  for (i = 0; i < ELEMENTS; i++) {
    arr.push(i);
  }
  end = new Date();
  deltaArray = end.getTime() - start.getTime();

  // list case
  start = new Date();
  for (i = 0; i < ELEMENTS; i++) {
    list.append(i);
  }
  end = new Date();
  deltaList = end.getTime() - start.getTime();

  console.log('Efficiency Test: Append ' + ELEMENTS + ' items.');
  console.log('Array:\t\t' + deltaArray + 'ms');
  console.log('LinkedList:\t' + deltaList + 'ms');
}

vageTest();
efficiencyTestPrepend(10000);
efficiencyTestAppend(1000000);