mongoose connect

1. Import the mongoose module to the Node.js application using the require method.

const mongoose = require('mongoose');

1. Establish a connection to the MongoDB database using the connect method of the mongoose object.

mongoose.connect('mongodb://localhost:27017/my_database', { useNewUrlParser: true, useUnifiedTopology: true });

1. Handle the connection events such as error and open using the connection object provided by the mongoose module.

const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
  console.log("Connected to the database");
});