Thiago's submission

How to run it

1. cd to apps/backend and execute docker compose up -d

How to test it

1. cd to apps/backend, execute docker compose up -d
2. execute yarn migrate to scaffold the database tables
3. run yarn test:e2e or yarn test.

Key points

These are the key decision I made and some context to their why's:

• No monorepo manager. I chose not to use a monorepo manager like NX here for simplicity.
• Focus on e2e tests. Usually when I start a new project that I know will change a lot, I tend to invest more into e2e tests. That's because these types of tests have a better "Resistance to Refactoring" - which means we have more freedom to change the underlying code, while keeping the behavior untouched and validated.
• Use of DSL for e2e tests. You'll notice e2e tests are using a DSL abstraction. This makes these tests more readable, maintainable, and also resistant to changes. It also fosters reusability, as we have application features exposed in a nice API.
• Use of Kysely (Query Builder) instead of ORM. ORM's can be quite cumbersome to setup, configure, and utilize. Kysely can be quickly adopted, and the developer don't have to learn a whole new API for dealing with the database - we can just use SQL as we know it.
• Separation of Layers. The wage module is subdivided into domain, application, infra, and presentation layers to improve its maintainability. However, I didn't apply vanilla clean architecture here - I don't use interfaces when communicating between layers. That's because early abstraction is a common pitfall, and I prefer to focus on solid E2E tests to give us freedom to change the code later, if necessary. For a more in-depth discussion of that, you can check out my article
• Exchange Ratios in APP. I chose to keep the exchange ratio between USD and ARS as a constant in the application - just for simplicity's sake again. In a real app this would probably come from a third-party API or the database.
• Use of both OOP and functional domain. The domain layer uses both OOP (Money class) and functional paradigm (withdraw). That's just to demonstrate how we can use both in that layer.