title: Angular2 RxJs Observables: filter vs map?
body: <p>Both the  Filter and Map <code>rxjs</code> functions seem to be ways to manipulate a <code>rxjs Observable</code>'s stream. After tinking with them and from examples I've seen, they both seem to do the same thing.</p>
  
  <p>What's the difference and when should I use one over the other?</p>