Mongoose の使用をお勧めします
リクエストごとにDB接続を作成していますが、これは正しい方法ではありません
const MongoClient = require('mongodb').MongoClient;
// Connection URL
const url = 'mongodb://localhost:27017';
// Database Name
const dbName = '<some db>';
// Use connect method to connect to the server
let db;
MongoClient.connect(url, function (err, client) {
assert.equal(null, err);
console.log("Connected successfully to server");
db = client.db(dbName);
});
app.get("/api/:object", async(req, res) => {
const collection = db.collection(req.params["object"]);
let result = await collection.find().toArray();
res.send(result);
});