How to delete a random element from the XML payload with the use of Script mediator in WSO2 ESB

In WSO2 ESB, we can use the Script Mediator manipulate a XML payload. Here I have used JavaScript/E4X for accessing/manipulating the elements.

Example XML payload;

<breakfast_menu>
   <food>
      <name>Belgian Waffles</name>
      <price>$5.95</price>
      <calories>650</calories>
   </food>
   <food>
      <name>Strawberry Belgian Waffles</name>
      <price>$7.95</price>
      <calories>900</calories>
   </food>
   <food>
      <name>Berry-Berry Belgian Waffles</name>
      <price>$8.95</price>
      <calories>900</calories>
   </food>

</breakfast_menu> 

Lets assume we want to remove the last food element (Berry-Berry Belgian Waffles); In this scenario, breakfast_menu is the root element and the set of children elements will be food. 

The length of the child elements (food) can be obtained as follows;

var payload = mc.getPayloadXML();
var length = payload.food.length();

Then delete the last element as follows; Here the index of the last element would be length-1

delete payload.cuidInfo[length-1];

Complete Script Mediator configuration would be as follows;

<script language="js">
    var payload = mc.getPayloadXML();
    var length = payload.food.length();
    delete payload.food[length-1];
    mc.setPayloadXML(payload);
</script>





The output of the script mediator would be as follows;

<breakfast_menu>
   <food>
      <name>Belgian Waffles</name>
      <price>$5.95</price>
      <calories>650</calories>
   </food>
   <food>
      <name>Strawberry Belgian Waffles</name>
      <price>$7.95</price>
      <calories>900</calories>
   </food>
</breakfast_menu>


NOTE:

<script language="js">var log = mc.getServiceLog();
         var message = mc.getPayloadXML();
         log.info(":: Message ::"+message);
         log.info(":: Message Header ::"+message..*::Header.*::To);
         delete message..*::Header..*::To;
         mc.setPayloadXML(message);</script>


<script language="js">var log = mc.getServiceLog();
         var message = mc.getPayloadXML();
         log.info(":: Message ::"+message);
         log.info(":: Message Header ::"+message..*::Header.*::To[0]);
         delete message..*::Header..*::To[0];
         mc.setPayloadXML(message);</script>