anchor.diff:    This cookbook contains recipes for common component communication scenarios
     in which two or more components share information.
   
  -  本文包含了当两个或多个组件之间需要共享信息时，常见的组件之间的交互方法。
  +  本食谱包含了常见的组件之间的交互方法，也就是两个或多个组件之间共享信息的方法。
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     .l-sub-section
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positive.code:   [Back to top](#top)
    
    [返回到顶部](#top)
  .l-main-section
  <a id="parent-to-child-setter"></a>
  :marked
    ## Intercept input property changes with a setter
    
    ## 通过setter截听Input属性值的变化Intercept
  
    Use an input property setter to intercept and act upon a value from the parent.
    
    使用一个Input属性setter，在父级拦截子级属性，并对属性值变化采取行动。
    
    The setter of the `name` input property in the child `NameChildComponent` 
    trims the whitespace from a name and replaces an empty value with default text.
    
    这个在子组件`NameChildComponent`的`name` Input属性的setter，修剪名字里面的空格和替换空值为默认文字。
    
  +makeExample('cb-component-communication/ts/app/name-child.component.ts')
  
  
negative.code:   ## Parent and children communicate via a service
    ## 父级和子级通过服务来交互
  
    A parent component and its children share a service whose interface enables bi-directional communication *within the family*.
    
    父级组件和它的子级组件共享一个服务，利用该服务*在本家庭之内*实现双向交互。
  
    The scope of the service instance is the parent component and its children. Components outside this component subtree have no access to the service or their communications.
    
    该服务实例的作用范围被限制在父级组件和其子级组件内。在这个组件子树之外的组件无法访问该服务或者它们之间的交互。
    
    This `MissionService` connects the `MissionControlComponent` to multiple `AstronautComponent` children.
    
  