Coupled infrastructure and core logic example

userController.js

//
//  Express controller route example of
//  coupled infrastructure with core logic
//
router.put('/user', async (req, res) => {
  //  db object is already added to req object when express is initialised
  const db = req.db

  const { userId, userName, userEmail } = req.body

  if (!userId || !userName || !userEmail) {
    throw new InvalidParamsException('Missing required params')
  }
  
  if (!isValidUserName(userName)) {
    throw new InvalidParamsException('Invalid username')
  }
  if (!isValidEmail(userEmail)) {
    throw new InvalidParamsException('Invalid email')
  }

  const users = db.get('users')

  const user = await users.findOne({
    userId
  })

  if (!user) {
    throw new UserNotFoundException('User not found')
  }
  
  const updatedUser = {
    ...user,
    userName,
    userEmail
  }

  await users.update({
    userId
  }, updatedUser)
  
  res.send('User updated')
})