MongoError:拓扑已关闭，请连接(client.close和client.connect问题)

const { MongoClient } = require('mongodb');

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

  try {
    await client.connect();
    console.log('Connected to MongoDB');

    // 在这里执行您的数据库操作
    const db = client.db('test');
    const collection = db.collection('example');
    const result = await collection.insertOne({ name: 'John Doe' });
    console.log('Insert result:', result);
  } catch (error) {
    console.error('Error:', error);
  } finally {
    // 确保在所有情况下都关闭客户端连接
    await client.close();
    console.log('Disconnected from MongoDB');
  }
}

main().catch(console.error);