anchor.diff:    back in the `DashboardComponent`
     Here's the fully revised `HeroesComponent` class:
   
  +  注意，我们将一个双元素的**链接参数数组**——路径和路由参数——传递到`router.navigate`，与之前在`DashboardComponent`中使用`[routerLink]`绑定一样。
  +
   +makeExcerpt('app/heroes.component.ts', 'class')
   
   :marked
  
positive.code: :marked
    ### Update the _HeroesComponent_ class.
  
    The `HeroesComponent` navigates to the `HeroesDetailComponent` in response to a button click. 
    The button's _click_ event is bound to a `gotoDetail` method that navigates _imperatively_
    by telling the router where to go.
  
    This approach requires some changes to the component class:
  
    1. Import the `router` from the Angular router library
    1. Inject the `router` in the constructor (along with the `HeroService`)
    1. Implement `gotoDetail` by calling the `router.navigate` method
    
  +makeExcerpt('app/heroes.component.ts', 'gotoDetail')
  :marked
  
negative.code:   We're going to display the hero detail on its own page and route to it as we did in the dashboard.
  
    这里我们不再展示完整的`HeroDetailComponent`了。
    我们要在它自己的页面中显示英雄详情，并像我们在控制台中所做的那样路由到它。
  
    We'll throw in a small twist for variety.
    We are keeping the "master/detail" style but shrinking the detail to a "mini", read-only version.
  