JS Data Structures - Linked List

linkedlist.js

function Node(data) {
  this.data = data;
  this.next = null;
}

function LinkedList() {
  this.head = null;
}

LinkedList.prototype.addNode = function(node) {
  if (this.head === null) {
    this.head = node;
  } else {
    var current = this.head;
    while (current.next != null) {      
      current = current.next;
    }
    current.next = node;
  }
};

LinkedList.prototype.countNodes = function() {
  var count = 0;
  var current = this.head;
  while (current != null) {
    count += 1;
    if (current.next != null) {
      current = current.next;
    } else {
      current = null;
    }
  }
  return count;
};

var list = new LinkedList();
list.addNode(new Node(6));
list.addNode(new Node(3));
list.addNode(new Node(33));

console.log('This is the head: ', list.head);
console.log('How many nodes? ' + list.countNodes());