title: Pass result of one resolve to another with Angular Router
body: <p>I know how to create multiple resolve classes for a route but I don't know how to pass the result of one resolve to another resolve.</p>
  
  <pre><code>// Example Route
  {
    path: 'book/:id',
    component: BookComponent,
    resolve: {
      document: BookResolve,
      title: BookTitleResolve
    }
  }
  </code></pre>
  
  <p>If the <strong>BookResolve</strong> returns a book object, how can you pass that book object to the <strong>BookTitleResolve</strong>?</p>
  
  <p>I have a title service that looks for the key <strong>title</strong> in data. I need to be able to generate the book title from the book object. This needs to be dynamic.</p>