mongoose connection node

mongoose.connect('mongodb://localhost:27017/test', {
  useMongoClient: true,
  connectTimeoutMS: 1000
})mongoose.connect('mongodb://localhost/myapp', { useNewUrlParser: true, useUnifiedTopology: true });
try {
  mongoose.connect(MONGODB_URI || 'mongodb://localhost/YOUR_DB_NAME', {
      useNewUrlParser: true,
      useUnifiedTopology: true
    }, () =>
    console.log("connected"));
} catch (error) {
  console.log("could not connect");
}