Retroactive/lib/data_structures/linked_list.js
function LinkedList() {

  this._length = 0;
  this.head = null;
  this.tail = null;

  // Read-only length property
  Object.defineProperty(this, 'length', {
    get: function () {
      return this._length;
    }.bind(this)
  });
}
function LinkedList() {

  this._length = 0;
  this.head = null;
  this.tail = null;

  // Read-only length property
  Object.defineProperty(this, 'length', {
    get: function () {
      return this._length;
    }.bind(this)
  });
}
function LinkedList ( ) { this . _length = 0 ; this . head = null ; this . tail = null ; // Read-only length property Object . defineProperty ( this , 'length' , { get : function ( ) { return this . _length ; } . bind ( this ) } ) ; }
Doubly-linked list
Doubly - linked list