getLeftSibling method

Node? getLeftSibling(
  1. Graph graph,
  2. Node node
)

Implementation

Node? getLeftSibling(Graph graph, Node node) {
  if (!hasLeftSibling(graph, node)) {
    return null;
  } else {
    var parent = predecessorsOf(node).first;
    var children = successorsOf(parent);
    var nodeIndex = children.indexOf(node);
    return children[nodeIndex - 1];
  }
}