We want to make a booking solution for one hotel. The first 2 user stories are:

• As a user I want to see all free rooms.
• As a user I want to book a room.

The Booking struct contains

• client id
• room name
• arrival date
• departure date

And the Room struct contain only

• room name

In order to face a scalable solution I used tactical DDD with CQRS on top of Hexagonal Architecture. For that there're 3 main folders 👇

• src/application 👉 Contains all the top level services divided into commands, queries and events.
• src/domainmodel 👉 Contains all the business logic. For business logic I considered all the elements that change application state. In this case, the bookings. So this leaves all the reads out of the domainlayer and this also implies queries & query handlers.
• src/infrastructure 👉 Implementation details such as persistence.

As for the delivery mechanism, I used NestJs as framework of choice given it's maturity and all the built-in features it comes with. Features used 👇

• Delivery Mechanism 👉 NestJs
• Persistence layer 👉 TypeORM
• CQRS framework 👉 NestJs CQRS

For this you will need to have Docker installed. Then run

docker compose up -d

Once everything is running, just point your browser to

https://127.0.0.1:3000/api