title: Filter an array for a subset of object keys
body: <p>Suppose I have:</p>
  
  <pre><code>var JSONArray = [{'key1':'a1','key2':'a2','key3':'a3'},
                   {'key1':'b1','key2':'b2','key3':'b3'},
                   etc 
                  ];
  </code></pre>
  
  <p>How do I get an array that will hold the same objects, but without <code>'key3'</code>?</p>