title: Creating a custom Angular filter with TypeScript
body: <p>I'm trying to work out the best way of creating a custom Angular Filter with TypeScript.</p>
  
  <p>All the code samples I see use something like:</p>
  
  <pre><code>myModule.filter( "myFilter", function()
  {
      return function( input )
      {
          //  filter stuff here
          return result;
      }
  }
  </code></pre>
  
  <p>... which works, but seems messy as I want to keep all my filter code separate. So I want to know how to declare the filter as a separate file (eg filters/reverse-filter.ts) so I can create it like:</p>
  
  <pre><code>myModule.filter( "filterName", moduleName.myFilter );
  </code></pre>
  
  <p>... the same way you would for Controllers, Services etc.</p>
  
  <p>The documentation for TS and Angular together seems pretty thin on the ground, especially where filters are concerned - can anyone help out?</p>
  
  <p>Cheers!</p>