for mongoosjs what connection do i use code example

Example 1: mongoose connection node

mongoose.connect('mongodb://localhost/myapp', { useNewUrlParser: true, useUnifiedTopology: true });

Example 2: mongoose connect to URL of atals

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