const MongoClient = require('mongodb').MongoClient;
MongoClient.connect('내 DB 접근 url', function(error, client){
if(error) return console.log(error);
app.listen(포트번호, function(){});
})
var db;
db = client.db('DB 이름');
db.collection('collection 이름').insertOne({_id : 0, name : 'Yu', age : 27})