title: Angular Http - toPromise or subscribe
body: <p>I have watch a few courses on Angular and have found there are different ways to manage data from an Http request.</p>
  
  <ul>
  <li>Using Observables, <code>.map()</code>, <code>.subscribe()</code></li>
  <li>Using Promises, <code>.toPromise()</code>, <code>.then()</code>, <code>.catch()</code></li>
  </ul>
  
  <p>I have used <code>toPromise()</code> in my application as I find it similar to the AngularJS Http services. </p>
  
  <p>In what scenario would I need to use Observables?</p>