Isolated update user logic from express route

updateUser.js

//
//  Isolated update user logic from express route
//  Still coupled with mongo db client
//
async function updateUser ({db, updateParams}) {
  const { userId, userName, userEmail } = updateParams

  //  validate request params
  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()
  }
  
  const updatedUser = {
    ...user,
    userName,
    userEmail
  }
  
  await users.update({
    userId
  }, updatedUser)
})