title: Use Angular constant outside of angular
body: <p>I know it is not a good practice to use Angular services outside of angular but nevertheless it's very interesting for me, for example I have 
  <code>.constant('APIprefix','/api')</code></p>
  
  <p>how can I retrieve <strong>APIprefix</strong> value outside of angular scope? For instance from other js file which is not in angular scope.</p>