Bidirectional MVVM (for iOS, Swift 4)

Why?

Because I wanted to see how I can do "real" MVVM, that dynamically exchanges data between view and model (not, as in most examples, only sends data to view).

In addition it's a real-world example of Swift 4 key path usage.

Structure of project

Project is divived in 4 groups, to keeps things simple:

• Binding - KeyPathBinding, for simplicity it handles only String data types
• Model - Credentials model (with 2 string fields)
• ViewModel - you should do all model and view operation via LoginViewModel class
• Controller - in which you bind UITextFields to our view model

Important note about structs

This example works for structs, however each binding creates it's own struct copy.