mongodb 遇到问题-查询单个需要包装id

mongodb，get字符查询需要传入特定的包装id才能识别

 const ObjectID = require('mongodb').ObjectID

 exports.queryOne = (req, res) => {
     console.log(req.body)
     MongoClient.connect(url, function(err, client) {
             assert.equal(null, err);
             const db = client.db(dbName);
             // Get the documents collection
             const collection = db.collection('documents');
             const id = new ObjectID(req.params.id)
             console.log(id)
             // Find some documents
             collection.find({'_id':id}).toArray(function(err, docs) {
                 assert.equal(err, null);
                 res.status(200).json(docs)
                 client.close();
             });
         });
     }