Add To Head - part 2

https://subscription.packtpub.com/video/programming/9781800206878/p2/video2_4/-add-to-head-part-2

by Dominic Myers

JavaScript

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

function Node(value, next, prev) {
  this.value = value;
  this.next = next;
  this.prev = prev;
}

LinkedList.prototype.addToHead = function(value) {
  var newNode = new Node(value, this.head, null);
  if (this.head) {
    this.head.prev = newNode;
  } else {
    this.tail = newNode;
  }
  this.head = newNode;
}