This is what I think a typical app architecture wi...

# multiplatform

[Daniele B]

This is what I think a typical app architecture will be.
With third parties starting to release KMP libraries too.

[Jeff]

Hey @Daniele B thanks for this! How do I structure a multiplatform library that is basically an API wrapper of a third-party payment service. Should the library include View Model and Data Repository?

[Daniele B]

@Jeff This architecture I am showing fits to apps that use the new declarative UIs.
If you just want to have a KMP library to be used in an existing app, you don’t have to stick to this architecture.
In my opinion a KMP ViewModel makes a lot of sense in an MVI-declarativeUI app.
But at the same time KMP is so flexible, that it can adapt to any architecture.

[Daniele B]

A clear distinction between ViewModel and Data Repository helps to organize the code in a clean way.
The ViewModel just defines what is the data to be shown on the UI, and deals with stuff like localization, accessibility text, etc.

[Daniele B]

The Data Repository is the layer that collects the data from different sources (network calls, local settings, databases) and manages any caching mechanisms.

[Daniele B]

The UI layer shows the data held in the ViewModel.

[Daniele B]

The ViewModel queries any data from the Data Repository, without caring what’s the actual source.

[Daniele B]

The Data Repository manages all the sources, and provides the data required by the ViewModel.

[Daniele B]

The Data Repository is also what connects to plaftorm-specific services, such as location, or in-app-purchasing or bluetooth, etc.

[Daniele B]

If you want to use a Watch OS or Wear OS app, you can keep the same Data Repository, and just design a new View Model, which would typically be a stripped down version of the full app View Model

[Daniele B]

View Model is basically the place where you define your user interaction and usability