 
   sortNodes: (compare, t) ->
     if @nodes.length == 1
-      return
+      return []
 
     anims = []
     anims.push(@makeLineupAnim(default_node_radius*2, .1, t))

            pos: ( x: x + children_bounds[idx].width/2, y:
                      default_node_radius * 3 )
          )
          x += children_bounds[idx].width + default_node_radius

      width: width + default_node_radius * 2
      height: height + default_node_radius * 2

    getBounds(tree)


          children_width += cb.width
          children_max_height = Math.max(children_max_height, cb.height)

        width = Math.max(width, children_width)
        height = Math.max(height,
          children_max_height + 2 * default_node_radius)

