Linked Lists via. FEM

linkedlists-fem.js

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

function LinkedList (headValue) {
  if (headValue === undefined) console.log("Head must be defined");
  this.head = new Node(headValue);
  this.tail = this.head;
}

LinkedList.prototype.forEach = function (callback) {
  var node = this.head;
  while (node) {
    callback(node.value);
    node = node.next;
  }
}

LinkedList.prototype.print = function () {
  var result = [];
  this.forEach(function (value) {
     result.push(value);         
    });
  return result.join(', ');
  )
}

LinkedList.prototype.insertAfter = function(node, value) {
  // get reference to former next
  var oldNext = node.next;
  // create new node
  var newNext = new Node(value);
  // store it as the new next
  node.next = newNext;
  // set next for the new node to old next
  newNext.next = oldNext;
  // if reference node is tail, set tail to newNext
  if (this.tail === node) this.tail = newNext;
  return newNext;
}