title: Find key from value in associative array containing JSON
body: <p>I've searched and found a few similar-but-not-quite answers.</p>
  
  <p>I have an array <code>SongList</code> (showing 2 items for brevity...) - the first pair is a key, the second pair is some JSON.</p>
  
  <pre><code>SongList={
      song_1:{title:"title of first song",artist:"the artist",mp3:"http://mysite/song1.mp3"},
      song_2:{title:"title of second song",artist:"the artist",mp3:"http://mysite/song2mp3"}
      ...
  };
  </code></pre>
  
  <p>I would like to be able to retrieve the key (<code>song_1</code> or <code>song_2</code>) given the <code>title</code> in the value.</p>
  
  <p>I will be looping through a temporary array of <code>i</code> items, each item in this array would have a match in <code>SongList</code> and I would save the key (<code>song_1</code>, <code>song_2</code>) in a final array.</p>