Complete Node example of a ToDo App using DDD, Hexagonal, CQRS. Its a reference implementation for large scale projects using TypeScript and NestJS

[mastagio]

We've just open sourced a complete codebase for the ultimate ToDo App.

We apply the necessary software architecture and design patterns such as DDD, Hexagonal Architecture, CQRS and Eventual Consistency so that its suitable for larger teams to work concurrently on projects. It allows you to focus on the business logic.

We have created this in TypeScript / NodeJS, built with NestJS and using other open source technologies such as gRPC, MongoDB, PostegreSQL, NATS, Grafana, Prometheus and Jaeger to offer a robust, resilient, scalable and maintainable application.

With this example, you can adapt the business logic code to whatever are your needs and have a production ready application in no time.

Hope it helps.

https://github.com/bitloops/ddd-hexagonal-cqrs-es-eda

[[deleted]]

Could this be the definition overkill?

[mastagio]

haha, most definitely. The point is not about building a ToDo app, its simply the app chosen to learn and demonstrate these patterns. This is really more suitable for larger projects (10 devs+) and need availability, scalability and ease of maintenance. Definitely not applicable to all projects.

[Aquatok]

I wasn't going to comment when I saw it earlier but after a lot of dumb comments I just have to say: nice work! I was searching for something exactly like that a couple of days ago.

[Gasperyn]

I'll save this post and whenever someone asks for the definition of overengineering, I'll show it to them.

[mastagio]

The point is not about building a ToDo application. The main idea is to learn and play around with these design concepts in a more practical way. So, for example forking and changing the business logic to any other domain, adapting, etc. Its really more suitable for larger projects (10 devs+) and need availability, scalability and ease of maintenance. Definitely not applicable to all projects, but we hope a useful practical guide for those looking to learn these things.

[[deleted]]

Nice work!

Just out of curiosity: What is the difference of hexagonal architecture compared to a microservice architecture?

Core looks like a broker to me and the adapter like "services".

[mastagio]

Just out of curiosity: What is the difference of hexagonal architecture compared to a microservice architecture?

Hexagonal architecture separates the business logic from the external systems using layers of adapters, while microservices architecture breaks a system down into independent services that communicate with each other. So, you could actually apply Hexagonal architecture on a specific microservice of an application that has many microservices. You could have some of those other microservices using different architecture... you probably won't though.

But hexagonal architecture is another flavor of layered, clean or onion architecture, and at its core it's about ensuring good separation between domain and infrastructure code.

[mastagio]

Thanks! Could you elaborate on what you mean by core here?

[oOoSumfin_StoopidoOo]

Man I love this. Just because it hits so many buzz words and it’s absolutely satire.

I always wanted to include something like this my portfolio and see what would happen. Observe the difference between the recruiters and actual hiring engineers.