anchor.diff:    <a id="elvis"></a>
     ### The Elvis operator ( ?. ) and null property paths
   
  -  The Angular **Elvis operator (`?.`)** is a fluent and convenient way to guard against null and undefined values in property paths.
  +  The Angular **Elvis operator (`?.`)** &mdash; perhaps better described as the "safe navigation operator" &mdash; is a fluent and convenient way to guard against null and undefined values in property paths.
     Here it is, protecting against a view render failure if the `currentHero` is null.
   // #enddocregion expression-operators-elvis-1
   +makeExample('template-syntax/ts/app/app.component.html', 'elvis-2')(format=".")
  
positive.code: 
    Many of us are familiar with the component/template duality from our experience with model-view-controller (MVC) or model-view-viewmodel (MVVM). In Angular,  the component plays the part of the controller/viewmodel, and the template represents the view.
  
    Let’s find out what it takes to write a template for our view. We’ll cover these basic elements of template syntax:
  
    * [HTML](#html)
    * [Interpolation](#interpolation)
  
negative.code:   * [Local template variables](#local-vars)
    * [Input and output properties](#inputs-outputs)
    * [Template expression operators](#expression-operators)
      * [pipe](#pipe)
      * ["elvis" (?.)](#elvis)  
  // #enddocregion intro
  .l-sub-section
    :marked
      The [live example](/resources/live-examples/template-syntax/ts/plnkr.html) 
      demonstrates all of the syntax and code snippets described in this chapter.
    
  // #docregion html-1
  .l-main-section
  :marked
  