Mongoose로 Node.js와 연결 시 DeprecationWarning

// mongodb setup
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/mydb');

var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
    // we're connected!
    console.log('connected successfully');
});

다음과 같은 Warning이 발생함

(node:1876) DeprecationWarning: `open()` is deprecated in mongoose >= 4.11.0, use `openUri()` instead, or set the `useMongoClient` option if using `connect()` or `createConnection()`. See http://mongoosejs.com/docs/connections.html#use-mongo-client

// mongodb setup
var mongoose = require('mongoose');
var promise = mongoose.connect('mongodb://localhost/mydb', {
  useMongoClient: true
});

var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
    // we're connected!
    console.log('connected successfully');
});

useMongoClient 옵션을 사용해 Warning 해결