code: function(node, msg) {
          if (node.complete === "complete") {
              return msg;
          }
          try {
              return (node.prop||"payload").split(".").reduce(function (obj, i) {
                  return obj[i];
              }, msg);
          } catch (err) {
              return; // undefined
          }
      }
docs: given a node and a message, extract the incoming object