Better Form Model Validation
Earlier this month, I wrote about validating temporary models for forms. The validation returned .complete or .incomplete, which doesn't help much when you want to show what did go wrong. So I came up with a richer validation syntax.
Validate Temporary Form Models
Ian Keen posted an article about type-safe temporary models. You would use them like scratch pad contexts in Core Data: in forms, you collect information into these temporary models and then generate your real objects from them.
Separate Read Model from Write Model to Support Complex Forms
One thing that repeatedly messes up the conceptual purity of a view model is figuring out which entity should be mutated upon user interaction. Part of this purity stems from the fact that a view model is best served as view data to stress that it doesn't contain much (business) logic. Making the data mutable introduces a lot of problems figuring out what that view model really is.