Question / Feature Request > generate ngrx code with domain or feature lib

[pascalbe-dev]

While many apps probably do work fine with simple BehaviorSubjects within the facades, it would be great to be able to scaffold ngrx code when generating a (domain?) library via a flag, so it's easier for developers to generate that code in a consistent manner across a monorepo.

While technically, this shouldn't be too hard by using the nx ngrx schematics, I'm wondering how to structure the code reasonably. Nx recommends having feature level states, however, the domain-driven setup we have with this plugin requires the state of all feature libs for a domain to live inside the domain library. Would you have separate Feature-States within Domain-Feature-Modules and import them in the specific Feature-Modules or would you add all ngrx Stuff to the Domain-Module?

Do you have any examples following some best practices about structuring an ngrx managed state with the library structure of the nx-ddd-plugin? The demo apps all make use of BehaviorSubjects only to manage the state.

[manfredsteyer]

Hi Pascal,

in this case, I would add state management to the domain layer. If it has a facade, the facade shields details of state management from the consumer.

I've implemented this here within a workshop in the booking domain:

https://github.com/manfredsteyer/workshop-fest-2020-05/tree/master/libs/booking/domain/src/lib

Best wishes, Manfred

[pascalbe-dev]

Hi Manfred, it sounds reasonable to hide the state management details behind the facade.

The only thing, which might be a bit of work, if you implement it that way, is handling route navigation. Nx has a utility operator for it which requires having access to the component, which handles the route (see here). Using this utility would not be possible then since we do not want the dependency from domain lib to feature lib implementing the routes and components.

Two options:

• implementing router store action handling by hand within the domain layer w/o using a component reference (--> couples state management logic in domain layer with the way routes are organized)
• handling routes within component and calling facade "load" method or something similar (clutters component; handles state updates (router updates) not directly via the store, which also feels kind of bad)

I'd love to hear your take on that navigation handling topic and how to cleanly implement that in this context.

Apart from that, I'm also trying to prepare a PR here. Your suggestion with the ngrx option for the domain schematic sounds great.

[manfredsteyer]

I'd go with the 2nd option and call a method provided by the facade in the component or in a resolver.

Looking forward to your PR.

If you need any information, don't hesitate to reach out.

[pascalbe-dev]

Nice, this seems to be added in 1.1.0 👍 great work @peterbsmith2