anchor.diff:   * ascending order this way:
    *
    *     Colors: <ul>
  - *       <li ng-repeat='color in colors | orderBy:""'>{{color}}</li>
  + *       <li ng-repeat="color in colors | orderBy:''">{{color}}</li>
    *     </ul>
    *
    * That would result in:
  
positive.code:  *
   * If you want to list the authors sorted by `lastName`, you would use
   *
   *     <li ng-repeat='author in authors | orderBy:"lastName"'>
   *       {{author.lastName}}, {{author.firstName
   *     </li>
   *
   * The string expression, `"lastName"`, indicates that the sort should be on the
   * `lastName` property of each item.
   *
   * Using the lesson from the previous example, you may sort in reverse order of
   * lastName using either of the two methods.
   *
   *     <!-- reverse order of last names -->
   *     <li ng-repeat='author in authors | orderBy:"-lastName"'>
   *     <!-- also does the same thing -->
   *     <li ng-repeat='author in authors | orderBy:"lastName":true'>
   *
   * Note that, while we only discussed string expressions, such as `"lastName"`
   * or the empty string, you can also directly provide a custom callable that
   * will be called to transform the element before a sort.
   *
   *     <li ng-repeat='author in authors | orderBy:getAuthorId'>
   *
   * In the previous snippet, `getAuthorId` would evaluate to a callable when
   * evaluated on the [Scope] of the `<li>` element.  That callable is called once
  
negative.code:  * then by first name when the last names are equal.  You would do that like
   * this:
   *
   *     <li ng-repeat="author in authors | orderBy:['lastName', 'firstName']">
   *
   * The items in such a list may either be string expressions or callables.  The
   * list itself might be provided as an expression that is looked up on the scope
  