anchor.diff:  
     - [What are structural directives?](#definition)
     - [*NgIf* case study](#ngIf)
  -  - [Group sibling elements with &lt;ng-container&gt;](#ng-container)
     - [The asterisk (*) prefix](#asterisk)
     - [Inside *NgFor*](#ngFor)
       - [microsyntax](#microsyntax)
  
positive.code:   Before applying a structural directive, you might want to pause for a moment 
    to consider the consequences of adding and removing elements and of creating and destroying components.
  
  a#ngcontainer
  a#ng-container
  .l-main-section
  
negative.code:   - [Inside the *NgSwitch* directives](#ngSwitch)
    - [Prefer the (*) prefix](#prefer-asterisk)
    - [The &lt;template> element](#template)
    - [Group sibling elements with &lt;ng-container&gt;](#ng-container)
    - [Write a structural directive](#unless)
  
    Try the <live-example></live-example>.
  