anchor.diff:    Angular创建它，渲染它，创建并渲染它的子组件，在它被绑定的属性发生变化时检查它，并在它从DOM中被移除前销毁它。
   
     Angular offers **lifecycle hooks**
  -  that provide visibility into these key moments and the ability to act when they occur.
  -  
  -  Angular提供了**生命周期钩子**，把这些关键时刻暴露出来，赋予我们在它们发生时采取行动的能力。
  +  that provide visibility into these key life moments and the ability to act when they occur.
  +  
  +  Angular提供了**生命周期钩子**，把这些关键生命时刻暴露出来，赋予我们在它们发生时采取行动的能力。
   
     A directive has the same set of lifecycle hooks, minus the hooks that are specific to component content and views.
     
  
positive.code:   There's no [need to wait](#wait-a-tick). 
    
    该组件的`doSomething`方法立即更新了组件被绑定的`comment`属性。
    它[不用等](#wait-a-tick)下一拍。
    
    Recall that Angular calls both *AfterContent* hooks before calling either of the *AfterView* hooks.
    Angular completes composition of the projected content *before* finishing the composition of this component's view.
  
negative.code:     Misko Hevery，Angular项目的头，在[这里解释](http://misko.hevery.com/code-reviewers-guide/flaw-constructor-does-real-work/)了你为什么应该避免复杂的构造函数逻辑。
    
  :marked
    Don't fetch data in a component constructor.
    You shouldn't worry that a new component will try to contact a remote server when
    created under test or before you decide to display it.
  