Stack-based Navigation - How can shared features be composed into multiple parent features?

[p4checo]

Hi 👋🏼

First of all, thanks for the awesome work being done for the community and advancement of the iOS "race" 🙇🏼

Considering that NavigationStack (and NavigationStackStore) don't seem to allow nesting, are there any ideas to enable nesting child features with their own navigation stack setup (Path.State, Path.Action) in a parent feature, while preserving a single navigation root in the parent?

As apps naturally grow in complexity, it's easy to see some root level features/views becoming huge beasts as the number of possible stack navigations increase if we need to have them "flattened" on the root feature.

Additionally, this has a big impact on feature composition, most likely leading to duplicated navigation logic as we can't reuse a child feature's navigation flow in two separate parent features (each with its own navigation stack).

Consider the following setup:

• Feature A has the paths to sub-Features B, C, D
• Feature X has the paths to sub-Features C, Y, Z
• Feature C has the paths to sub-feature L, M, N (and is reused by both Features A and X)

Using the current stack navigation tools, it seems we would have to replicate the child feature C's navigation handling in both features A and X, because they own the StackState which is what drives the navigation stack. So, in each of the parent features A and X we would need to add handling for feature C's sub-features, i.e. add them to the Path.State and Path.Action, as well as duplicating the "internal" logic of Feature C to orchestrate navigating between its sub-features L, M, N.

In theory it seems to be a case of merging/flattening StackStates and StackActions, but the reducer composition logic is making my brain hurt a bit 😅

At the SwiftUI level I think that the existing tools should already support this, as the views returned by CaseLet's inside the NavigationStackStores destination closure could "drill down" to other SwitchStore + CaseLet providing the sub-sub-feature's views (and so on). The caveat is that no sub-feature's can have a NavigationStackStore though.

Thanks! 🙏🏼

[TiagoSantosSilva]

@p4checo did you end up finding a solution for this? I'm trying to achieve the same result that you mentioned but I'm having no success.

[p4checo]

Hi @TiagoSantosSilva,

Unfortunately no. I intend to have a go at it eventually but didn't have the opportunity yet.