expandedNodeIds property

Implementation

Set<String> get expandedNodeIds {
  final ids = <String>{};
  void collect(LayoutNode n) {
    if (n.isExpanded) {
      ids.add(n.id);
    }
    n.children.forEach(collect);
    if (n.hiddenChildren != null) {
      n.hiddenChildren!.forEach(collect);
    }
  }

  collect(root);
  return ids;
}