anchor.diff:    Any of those injectors could have its own instance of the service.
   
     If we defined a `RestoreService` provider only on the root component,
  -  we would have exactly one instance of that service and it would be shared across the entire application. 
  -  
  +  we would have exactly one instance of that service and it would be shared across the entire application.
  +
     That’s clearly not what we want in this scenario. We want each component to have its own instance of the `RestoreService`.
     Defining (or re-defining) a provider at the component level creates a new instance of the service for each new instance
  -  of that component. We've made the `RestoreService` a kind of "private" singleton for each `HeroEditComponent`, 
  +  of that component. We've made the `RestoreService` a kind of "private" singleton for each `HeroEditComponent`,
     scoped to that component instance and its child components.
   
     <!--
  
positive.code: 
    Our `HeroEditComponent` uses this services under the hood for it’s `hero` property. It intercepts the `get` and `set` method to delegate the actual work to our `RestoreService` which in turn makes sure that we won’t work on the original item but on a copy instead.
  
    At this point we may be scratching our heads asking what this has to do with component injectors? 
    If closely at the metadata for our `HeroEditComponent`. Notice the `providers` property.
  
  +makeExample('hierarchical-dependency-injection/ts/app/hero-editor.component.ts', 'providers')
  :marked
    This adds a `RestoreService` provider to the injector of the `HeroEditComponent`. 
    Couldn’t we simply alter our bootstrap call to this?
  
  +makeExample('hierarchical-dependency-injection/ts/app/boot.ts', 'bad-alternative')
  
negative.code:   that parallel an application's component tree.
    We can re-configure the injectors at any level of that component tree with
    interesting and useful results.
  
    In this chapter we explore these points and write some code.
  
    [Live Example](/resources/live-examples/hierarchical-dependency-injection/ts/plnkr.html).
  
  .l-main-section
  