CastError:对于模型"Contact“的路径"_id”处的值“ObjectId”(类型字符串)，强制转换为ObjectId失败

const express = require('express');
const { MongoClient, ObjectId } = require('mongodb');

const app = express();
const port = 3000;

async function run() {
  const client = await MongoClient.connect('mongodb://localhost:27017', { useUnifiedTopology: true });
  const db = client.db('testdb');
  const contactsCollection = db.collection('contacts');

  app.get('/contacts/:id', async (req, res) => {
    const id = req.params.id;

    if (!ObjectId.isValid(id)) {
      return res.status(400).send('Invalid ObjectId');
    }

    try {
      const contact = await contactsCollection.findOne({ _id: new ObjectId(id) });
      if (!contact) {
        return res.status(404).send('Contact not found');
      }
      res.json(contact);
    } catch (err) {
      if (err.name === 'CastError') {
        return res.status(400).send('Invalid ObjectId');
      }
      throw err;
    }
  });

  app.listen(port, () => {
    console.log(`Server running on http://localhost:${port}`);
  });
}

run().catch(console.dir);