如何从VIS.js网络中获取所有节点Ids

// 创建VIS.js网络实例
var container = document.getElementById('network');
var data = {
  nodes: [
    { id: 1, label: 'Node 1' },
    { id: 2, label: 'Node 2' },
    { id: 3, label: 'Node 3' }
  ],
  edges: [
    { from: 1, to: 2 },
    { from: 2, to: 3 }
  ]
};
var options = {};
var network = new vis.Network(container, data, options);

// 获取所有节点的Ids
var nodes = network.getNodes();
var nodeIds = [];
for (var nodeId in nodes) {
  if (nodes.hasOwnProperty(nodeId)) {
    nodeIds.push(nodeId);
  }
}

console.log(nodeIds); // 输出所有节点的Ids