title: javascript find parent of array item
body: <p>I have an array item like this:</p>
  
  <pre><code>var array = USA.NY[2];
  // gives "Albany"
  
  {"USA" : {
    "NY" : ["New York City", "Long Island", "Albany"]
  }}
  </code></pre>
  
  <p>I want to find the state from just having the array. How do I do this? Thanks.</p>
  
  <pre><code>function findParent(array) {
    // do something
    // return NY
  }
  </code></pre>