flattenTree method

List<TreeRow> flattenTree({ required List<Map<String, dynamic>> rows, required Set<String> expandedIds, int depth = 0, String parentId = '', })

Flatten tree data into visible rows based on expanded state Only includes rows whose parents are expanded

Implementation

List<TreeRow> flattenTree({
  required List<Map<String, dynamic>> rows,
  required Set<String> expandedIds,
  int depth = 0,
  String parentId = '',
}) {
  final result = <TreeRow>[];

  for (var i = 0; i < rows.length; i++) {
    final row = rows[i];
    final rowId = _generateRowId(row, i, parentId);
    final hasChildren = _hasChildren(row);

    result.add(TreeRow(
      data: row,
      depth: depth,
      hasChildren: hasChildren,
      id: rowId,
    ));

    // Recursively add children if this row is expanded
    if (hasChildren && expandedIds.contains(rowId)) {
      final children = (row['_children'] as List)
          .whereType<Map<String, dynamic>>()
          .toList();

      result.addAll(flattenTree(
        rows: children,
        expandedIds: expandedIds,
        depth: depth + 1,
        parentId: rowId,
      ));
    }
  }

  return result;
}