使用$sample的MongoDB和Node.js聚合没有返回文档

const MongoClient = require('mongodb').MongoClient;

const uri = 'mongodb://localhost:27017';
const client = new MongoClient(uri, { useNewUrlParser: true });

client.connect(err => {
  if (err) {
    console.error('Failed to connect to MongoDB:', err);
    return;
  }

  const collection = client.db('your-database').collection('your-collection');

  collection.aggregate([
    { $sample: { size: 1 } }
  ]).toArray((err, docs) => {
    if (err) {
      console.error('Failed to execute aggregation:', err);
      return;
    }

    if (docs.length === 0) {
      console.log('No documents found.');
      return;
    }

    console.log('Random document:', docs[0]);
  });

  client.close();
});