anchor.diff:  
   .callout.is-helpful
     header Name the constructor
  +
  +  header 命名构造函数
     :marked
       A **named** constructor displays clearly in the console log
       if the component throws a runtime error. 
       An **unnamed** constructor displays as an anonymous function (e.g., `class0`) 
       which is impossible to find in the source code.
   
  +    如果组件抛出运行时异常，**命名**的构造函数在控制台日志中显示得更清楚。
  +    **未命名**的构造函数显示为匿名函数（如，`class0`），不可能在源代码中找到它。
  +
   :marked
     ### Properties with getters and setters
  +
  +  ### 具有 getter 和 setter 的属性
   
     _TypeScript_ and _ES6_ support with getters and setters.
     Here's an example of a read-only _TypeScript_ property with a getter
     that prepares a toggle-button label for the next clicked state:
  +
  +  _TypeScript_ 和 _ES6_ 支持 getter 和 setter。
  +  下面是 _TypeScript_ 只读属性的例子，它有一个 getter，为下一次点击状态准备切换按钮的标签：
  +
   +makeExample('cb-ts-to-js/ts/app/hero-queries.component.ts', 'defined-property', 'ts/app/hero-queries.component.ts')(format='.')
   
   :marked
  
positive.code: :marked
    ## Interfaces
  
    A _TypeScript_ interface helps ensure that a class implements the interface's members correctly.
    We strongly recommend Angular interfaces where appropriate. 
    For example, the component class that implements the `ngOnInit` lifecycle hook method
    should implement the `OnInit` interface.
  
    _TypeScript_ interfaces exist for developer convenience and are not used by Angular at runtime.
    They have no physical manifestation in the generated JavaScript code.
    Just implement the methods and ignore interfaces when translating code samples from _TypeScript_ to JavaScript.
  
  +makeTabs(`
      cb-ts-to-js/ts/app/hero-lifecycle.component.ts,
  
negative.code:   [`@Component`](../api/core/index/Component-decorator.html) decorator function whose
    argument is an object literal with metadata properties.
  
    当用 _TypeScript_ 或 _带装饰器的 ES6_ 编写代码时，使用一个或多个*装饰器 (decorator)* 来修饰类，
    提供配置和元数据。
  
    In _plain ES6_, you provide metadata by attaching an `annotations` array to the _class_.
    Each item in the array is a new instance of a metadata decorator created with a similar metadata object literal.
  
    在_普通 ES6_ 中，通过向_类_附加一个`annotations`数组来提供元数据。
  
    In _ES5_, you also provide an `annotations` array but you attach it to the _constructor function_ rather than to a class.
  
    在_ES5_中，也是提供一个`annotations`数组，但把它附加到_构造函数_，而不是类。
  
    See these variations side-by-side:
  
    看一下这些变种：
  +makeTabs(`
      cb-ts-to-js/ts/app/hero.component.ts,
      cb-ts-to-js/js-es6-decorators/app/hero.component.es6,
  