如何使用Node js获取有向图输出

const graphlib = require('graphlib');
const { Graph } = graphlib;

function createDirectedGraph() {
  const graph = new Graph();

  graph.setNode('A');
  graph.setNode('B');
  graph.setNode('C');
  graph.setNode('D');

  graph.setEdge('A', 'B');
  graph.setEdge('A', 'C');
  graph.setEdge('B', 'D');
  graph.setEdge('C', 'D');

  return graph;
}

function main() {
  const graph = createDirectedGraph();

  // 输出节点数量
  console.log('节点数量:', graph.nodeCount());

  // 输出边数量
  console.log('边数量:', graph.edgeCount());

  // 输出节点列表
  console.log('节点列表:', graph.nodes());

  // 输出边列表
  console.log('边列表:', graph.edges());
}

main();