How to use the mongoose.disconnect function in mongoose

await user.save();

  console.warn('Creating channels...');
  await createChannels(serverIds);

  console.warn('Creating extra users...');
  await createUsersInServers(serverIds);

  console.warn('Adding friends to main user');
  // await addFriendsToUser(user);

  console.warn('Creating DM channels');
  // await createDMChannels(user);

  console.warn('Finished!');
  await mongoose.disconnect();
  process.exit();
}

db.on('error', function(error) {
    console.error('Error in MongoDb connection: ' + error);
    mongoose.disconnect();
  });
  db.on('connected', function() {

function forEachModelTypeComplete( err ) {
        console.log(err ? 'Error: ' : 'Seed completed with no errors', err);
        if ( config.odm && config.odm.enabled ) {
          mongoose.disconnect();
        }
    }
);

function exit() {
	mongoose.disconnect() 
}

const disconnect = () => {
  return mongoose.disconnect()
    .then((() => console.log('Mongoose: Disconnected.')));
};

function closeServer() {
    return mongoose.disconnect().then(() => {
        return new Promise((resolve, reject) => {
            console.log("Closing server");
            server.close(err => {
                if (err) {
                    return reject(err);
                }
                resolve();
            });
        });
    });
}

.then(() => {
  console.log('');
  console.log('Done!');
  mongoose.disconnect();
})
.catch(console.log);

function exit() {
	mongoose.disconnect()
}

            return new Promise((resolve, reject) => mongoose.disconnect(resolve));
        }

function disconnect(done) {
        log.debug('Disconnected from MongoDB');
        mongoose.disconnect(done);
      }