UI does not update based on the updateOrAppend of my state.todos

[idelfonsog2]

The Composable Architecture uses GitHub issues for bugs. For more general discussion and help, please use GitHub Discussions or the Swift forum first.

Hi there!
I have the following list in my state:

  var todos: IdentifiedArrayOf<Todo> = [/**omitted**/]

// my reducer has the following action:

case let .todos(id: identity, action: .toggled):
        guard var found = state.todos.filter({ $0.id == identity}).first else {
          return .none
        }
        
        found.isChecked.toggle()
        state.todos.updateOrAppend(found)
        return .none

1. But my UI is not reflecting the state change
2. the .debug() reducer add-on does prints the state change (true <--> false) of my list
3. When I print the state of my list all Todos state isChecked = false

What am I missing?

[iampatbrown]

@idelfonsog2 Can you include a small example so we can reproduce? Would need to see how your View is structured.

[idelfonsog2]

I can fork/update the project and post the link here.... but I grabbed the swift-composoble-artchitecture/Examples/Todos project and and modified the AppState and appReducer case to the above/below

// AppState
  var todos: IdentifiedArrayOf<Todo> = [
    Todo(description: "completed", id: UUID(), isComplete: false)
  ]


// appReducer
case .todo(id: let identity, action: .checkBoxToggled):
        guard var found = state.todos.filter({ $0.id == identity}).first else {
          return .none
        }
        
        found.isComplete.toggle()
        state.todos.updateOrAppend(found)
        return .none

no other changes in the repo example project were made

[idelfonsog2]

Let me know if you still need the fork on my account @iampatbrown Thank you for looking into this 🙏

[iampatbrown]

If that is the only change you made to the Todos example then isComplete is being toggled twice. Once by todoReducer and once by appReducer

swift-composable-architecture/Examples/Todos/Todos/Todo.swift

Lines 18 to 22 in 97c3a49

	let todoReducer = Reducer<Todo, TodoAction, TodoEnvironment> { todo, action, _ in
	switch action {
	case .checkBoxToggled:
	todo.isComplete.toggle()
	return .none

[mbrandonw]

(NB: Pat already answered while posting this, but thought I would go ahead and post it for more information)

Hi @idelfonsog2, there is a domain defined just for a single todo row, and it's the one responsible for flipping the boolean:

swift-composable-architecture/Examples/Todos/Todos/Todo.swift

Lines 20 to 22 in 97c3a49

	case .checkBoxToggled:
	todo.isComplete.toggle()
	return .none

Then the "todos" domain (i.e. the domain that handles an entire list of todos) layers on additional logic on top of the .checkBoxToggled action, such as sorting the todos to put completed ones at the bottom.

So, as Pat mentioned, with your code changes you are toggling the boolean twice. Once in the todo list domain and again in the todos domain.

If you can explain more of what you are trying to explore in this demo app we might be able to answer some questions.

[idelfonsog2]

Thank you very much! @mbrandonw I was inferring that behavior from the Reducer declaration after the todoReducer.forEach I just wasn't sure if it was the case. Hope this discussion also helps anyone out there!