code: function (oldChild) {
              var oldChildInNewTree = newNodeMap[oldChild.tagID];
  
              return oldChild.children && oldChildInNewTree && getParentID(oldChild) !== getParentID(oldChildInNewTree);
          }
docs: Looks to see if the element in the old tree has moved by checking its
  current and former parents.
  
  @return {boolean} true if the element has moved