public protocol StateUpdater : AnyStateUpdater

A StateUpdater is a Dispatchable that can be used to update the Store state configuration.

The StateUpdater is strongly tied to the state that it handles. This greatily simplifies the code written in normal situations. However, if you need to create updaters that are not strictly tied to a concrete state type (e.g., in a library) you can use AnyStateUpdater.

App Tips & Tricks

To futherly simplify the usage of a StateUpdater you can add to your application an helper protocol

/// assuming `AppState` is the type of your application's state
protocol AppStateUpdater: StateUpdater where StateType == AppState {}

By conforming to AppStateUpdater, you will get better autocompletion

  • The concrete state type that the updater manages



    associatedtype StateType : State
  • Updates the current state. It is important to note that updateState(currentState:) should be a pure function, that is a function that given the same input always returns the same output and it also doesn’t have any side effect. This is really important because it is an assumption that Katana (and related tools) makes in order to implement some functionalities.



    func updateState(_ state: inout StateType)



    the current configuration of the state. The method is meant to update the value of the state in place