const Sequelize = require('sequelize');

process.on('exit', () => {
  console.log('process.on exit');
});

const sequelize = new Sequelize('mysql://user:pass@localhost:3306/dbname', {
  dialect: 'mysql',
});

async function cleanDB() {
  await sequelize.authenticate();
  console.log('DB connection successfully established');
  return sequelize.transaction(async t => {
    const options = {
      transaction: t,
    };
    await sequelize.query('SELECT 1+1', options);
    console.log('Query was processed successfully');
  });
}

cleanDB()
  .then(() => {
    console.log('cleanDB finish successfully ');
  })
  .catch(err => {
    console.log('cleanDB throw error => ', err);
  })
  .finally(() => {
    sequelize
      .close()
      .then(() => {
        console.log('Connection has been close successfully.');
      })
      .catch(err => {
        console.error('Unable to close connect to the database:', err);
      });
  });