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:   (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=".")
  
  
negative.code: 
    A pipe takes in data as input and transforms it to a desired output.
    We'll illustrate by transforming a component's birthday property into
    a human-friendly date.
  
  +makeExample('pipes/ts/app/hero-birthday1.component.ts', null, 'app/hero-birthday1.component.ts')(format='.')
  
  