title: Mapbox filters based on array
body: <p>I have the following array:</p>
  
  <pre><code>test = ['a', 'b', 'c']
  </code></pre>
  
  <p>I would like to filter objects on the map if they exist in the array.
  Is it possible to use this filter with array:</p>
  
  <pre><code>mapObj.setFilter("hover", ['all', ["in", "letter", test[0]]]);
  </code></pre>
  
  <p>Or alternately, what is the best way to filter object that exist in the array?</p>