title: How to check if a particular element exists in SuperObject?
body: <p>I widely use the <code>SuperObject</code> JSON library. I need to be able to check if a particular element exists in an object or not. I can check the value of an element, for example an integer that doesn't exist returns <code>0</code>. However, <code>0</code> is one of the possible values if it does exist - so I can't depend on observing <code>0</code> for the element's existence. I checked the <code>ISuperObject</code> for methods that can do this (for example I'd expect something like <code>ISuperObject.Exists(const S: String): Boolean;</code>), but see nothing like this.</p>
  
  <p>How can I check if a particular element exists in the JSON object or not?</p>