From the preceding discussion, it seems like dependency injection is the better choice. Readability should not be too much of an issue, as we only have two layers of abstraction – handlers and engines. Therefore, let's migrate our code to use the dependency injection pattern.
First, remove the import statements from src/handlers/users/create/index.js and change the signature of the createUser function to include the create engine function and the ValidationError class:
function createUser(req, res, db, create, ValidationError) { ... }
Now, we need to inject these dependencies into the handler. In src/index.js, we are already using the injectHandlerDependencies function to inject the database client ...
