通过Node JS创建时，MongoDB不显示集合

const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017/mydatabase';

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  const dbo = db.db('mydatabase');
  dbo.createCollection('mycollection', function(err, res) {
    if (err) throw err;
    console.log('Collection created!');
    db.close();
  });
});

const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017/mydatabase';

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  const dbo = db.db('mydatabase');
  dbo.collection('mycollection').find({}).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});