title: How to create enum like type in TypeScript?
body: <p>I'm working on a definitions file for the Google maps API for TypeScript.</p>
  
  <p>And I need to define an enum like type eg. <code>google.maps.Animation</code> which contains two properties: <code>BOUNCE</code> and <code>DROP</code>.</p>
  
  <p>How should this be done in TypeScript?</p>