05-APropertyWrapperFromPointFree-BindableState.md

PointFree - Using the New Binding Functionality

This is a Stub

When using SwiftUI controls, you can eliminate a lot of boilerplate by using the @BindableState property wrapper.

Each annotated field is directly bindable to SwiftUI controls, like pickers, toggles, and text fields.

• define a State variable using the @BindableState property wrapper:

 struct SettingsState: Equatable {
  @BindableState var displayName: String = “”
}

conform the action type to BindableAction by collapsing all of the individual, field-mutating actions into a single case that holds a BindingAction generic over the reducer's State

• add a notation to your Action enum:

 public enum GoldenAction: Equatable, BindableAction {

• add a binding case (action) to your Action:

  case binding(BindingAction<SettingsState>)

even if you don’t need to take any action after the state changes, you still need to add a call to the binding function of Reducer at the closing delimiter of the reducer:

}
.binding()

if you need to take some action, then you want to match the case in your reducer:

 case .binding(\.displayName):
    state.displayName = String(state.displayName.prefix(16))
    return .none

It’s all pretty straightforward and will become second nature with use.

Next

.pct 18