JS Lesson 10

lesson10.js

function Node(name) {
  this.name = name;
  this.childNodes = new Array();
}

Node.prototype = {
  _lastChild: function() {
    if (this.childNodes.length > 0) {
        return this.childNodes[this.childNodes.length - 1];
    }
  }
};

Node.prototype = Object.create(Node.prototype);
Node.prototype.constructor = Node;

function Element() {
  Node.call(this);
  this.childNodes.push(new Node('lastChildNode'));
}

Element.prototype = Object.create(Element.prototype);
Element.prototype.constructor = Element;

Object.defineProperty(Element.prototype, 'lastChild', {
  enumerable: true,
  get: function() {
      return Node.prototype._lastChild.call(this);
  }
});

//A new Element will have the property 'lastChild'
// and that property will return the last child node
// as computed using Node's _lastChild function
// in the scope of Element with the property
// 'childNodes' as inherited from Node itself.