title: filters on ng-model in an input
body: <p>I have a text input and I don't want to allow users to use spaces, and everything typed will be turned into lowercase.</p>
  
  <p>I know I'm not allowed to use filters on ng-model eg.</p>
  
  <pre><code>ng-model='tags | lowercase | no_spaces'
  </code></pre>
  
  <p>I looked at creating my own directive but adding functions to <code>$parsers</code> and <code>$formatters</code> didn't update the input, only other elements that had <code>ng-model</code> on it.</p>
  
  <p>How can I change the input of that I'm currently typing in?</p>
  
  <p>I'm essentially trying to create the 'tags' feature that works just like the one here on StackOverflow.</p>