removeNode method

void removeNode(
  1. String nodeId
)

Removes a node from the graph along with all its connections.

This method will:

  1. Remove the node from the graph
  2. Remove it from the selection if selected
  3. Remove all connections involving this node
  4. Remove the node from any group annotations
  5. Delete empty group annotations that no longer contain any nodes

Triggers the onNodeDeleted callback after successful removal.

Implementation

void removeNode(String nodeId) {
  final nodeToDelete = _nodes[nodeId]; // Capture before deletion
  if (nodeToDelete == null) return;

  // Capture connections to emit events for
  final connectionsToRemove = _connections
      .where((c) => c.sourceNodeId == nodeId || c.targetNodeId == nodeId)
      .toList();

  runInAction(() {
    // Detach context for nodes with GroupableMixin before removal
    // This disposes MobX reactions and cleans up the context
    if (nodeToDelete is GroupableMixin<T>) {
      nodeToDelete.detachContext();
    }

    _nodes.remove(nodeId);
    _selectedNodeIds.remove(nodeId);
    // Remove from spatial index
    _spatialIndex.removeNode(nodeId);

    // Remove connections involving this node from spatial index first
    for (final connection in connectionsToRemove) {
      _spatialIndex.removeConnection(connection.id);
      // Also remove from path cache to prevent stale rendering
      _connectionPainter?.removeConnectionFromCache(connection.id);
    }

    // Then remove from connections list
    _connections.removeWhere(
      (c) => c.sourceNodeId == nodeId || c.targetNodeId == nodeId,
    );

    // Note: Groupable nodes (like GroupNode) are notified of deletions via MobX reaction
    // in _setupNodeMonitoringReactions that watches _nodes.keys for additions/deletions
  });
  // Fire event after successful removal
  events.node?.onDeleted?.call(nodeToDelete);
  // Emit extension events for removed connections first
  for (final connection in connectionsToRemove) {
    _emitEvent(ConnectionRemoved(connection));
  }
  // Emit extension event for removed node
  _emitEvent(NodeRemoved<T>(nodeToDelete));
}