 
   expand:(nodeView)->
 
-    nodeData = nodeView.getData()
-    nodeView.expand()
-    @listControllers[@getNodeId nodeData]?.getView().expand()
+    if nodeView?.getData?
+      nodeData = nodeView.getData()
+      nodeView.expand()
+      @listControllers[@getNodeId nodeData]?.getView().expand()
 
   collapse:(nodeView)->
 

    @nodes[@getNodeId nodeData] = {}

    if options.putDepthInfo
      if @nodes[@getNodePId nodeData]
        nodeData.depth = @nodes[@getNodePId(nodeData)].getData().depth + 1
      else
        nodeData.depth = 0


    # if node parent is present
    parentNodeView = @nodes[@getNodePId nodeData]
    if parentNodeView?.getData?
      prevNeighbor  = getPreviousNeighbor parentNodeView.getData()
      neighborIndex = @indexedNodes.indexOf prevNeighbor
      @indexedNodes.splice neighborIndex + 1, 0, nodeData
