anchor.diff:    We can chain pipes together in potentially useful combinations.
     In the following example, we chain the birthday to the `DatePipe` and on to the `UpperCasePipe`
     so we can display the birthday in uppercase. The following birthday displays as
  -  **<samp>APR 15, 1988</samp>**
  +  **<samp>APR 15, 1988</samp>**.
   
   +makeExample('pipes/ts/app/app.component.html', 'chained-birthday')(format=".")
   
  
positive.code: +makeExample('pipes/ts/app/exponential-strength.pipe.ts', null, 'app/exponential-strength.pipe.ts')(format=".")
  
  :marked
    This pipe definition reveals several key points
  
    * A pipe is a class decorated with pipe metadata.
  
  
negative.code:   (e.g., `currency:'EUR'`). If our pipe accepts multiple parameters, we separate the values with colons (e.g. `slice:1:5`)
  
    We'll modify our birthday template to give the date pipe a format parameter.
    After formatting the hero's April 15th birthday, it should render as **<samp>04/15/88</samp>**:
  
  +makeExample('pipes/ts/app/app.component.html', 'format-birthday')(format=".")
  
  