catch-block.js

catch (err) {
  // never forget to rollback
  await transaction.rollback() 
  
  if (err instanceof TypeError) {
    // we know now that we couldn't find a team
    return res.status(404).send('useful message regarding team not found')
  } 
  
  else if (err.message === 'tag not found') {
    // we know now that we couldn't find one of the tags by supplied id
    return res.status(404).send('...')
  }
  
  else {
    // something else happened (such as db connection, model constraints etc.)
    return next(err) // if you're using error handling middleware
    // else something like the following:
    // console.log(err.stack) // we will want to know what
    // res.status(500).send() // send a 500
  }
}