Composable Swift example

composable.swift

//
//  ContentView.swift
//  ReduxApp
//
//  Created by Damodar Namala on 28/09/22.
//

import SwiftUI
import Combine



@main
struct ReduxAppApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView(store: store)
        }
    }
}


struct ContentView: View {
    @ObservedObject var store: AppStore
    
    init(store: AppStore) {
        self.store = store
    }
    
    var body: some View {
        VStack {
            Image(systemName: "globe")
                .imageScale(.large)
                .foregroundColor(.accentColor)
            
            Text(store.state.name)
            Button {
                self.store.action(.setName("Damodar"))
            } label: {
                Text("Fetch")
            }

        }
    }
    private func fetch() {
        store.action(.setName("damodar"))
    }
}



typealias Reducer<State, Action> = (State, Action) -> State

enum AppAction {
    case setName(_ name: String)
}

struct AppState {
    var name = ""
}

final class Store<State, Action>: ObservableObject {
    @Published private(set) var state: State
    private let reducer: Reducer<State, Action>
    init(initialState: State,
         reducer: @escaping Reducer<State, Action>) {
        self.state = initialState
        self.reducer = reducer
    }
    func action(_ action: Action) {
        self.state = reducer(self.state, action)
    }
}

let reducer: Reducer<AppState, AppAction> = { state, action in
    var inState = state
    if case let .setName(name) =  action {
        inState.name = name
    }
    return inState
}

typealias AppStore = Store<AppState, AppAction>
var store = AppStore(initialState: .init(), reducer: reducer)