ErrorT

How to use Cats - XorT for error handling

Problem

In our codebase, most functions are returning one of A, Option[A], Future[A] and Future[Option[A]].

With Option, when we get None, we cannot identify the error.

Therefore, we don't know which error code to return for Frontend.

Intention

• use Xor to capture the error
• use XorT to work with Future
• avoiding comprehensive refactoring