This is interesting. The vertical slicing the author talks about sounds a lot like the conventional way to structure a functional component based UI. Components + state tree + selectors + reducers in a typical react app fit together in this way and it makes it very difficult to apply traditional OOP design patterns. This is a huge source of contention on my team between the front end and the back end developers who are all c# dotnet guys. If anyone has any suggestions on where to find more information about functional, flow-based application architecture I would really like to learn more.