Redux swift example

actions.swift

import Foundation

struct DashResponse {}

enum AppActions {
    case dashAction(DashActions)
    case envAction(EnvActions)
}

enum DashActions {
    case fetchingDash(fetchedAt: Date)
    case fetchedDash(receivedAt: Date, payload: DashResponse)
}

enum EnvActions {
    case login(userId: String)
}

reducers.swift

func dashReducer(state: AppState.DashState, action: DashActions) -> AppState.DashState {
    var dashState = state
    
    switch action {
    case .fetchingDash(let fetchedAt):
        dashState.isFetching = true
        dashState.fetchedAt = fetchedAt
    case .fetchedDash(let receivedAt, let payload):
        dashState.isFetching = false
        dashState.receivedAt = receivedAt
        dashState.contents = payload
    }
    
    return dashState
}

func envReducer(state: AppState.Env, action: EnvActions) -> AppState.Env {
    var state = state
    
    switch action {
    case .login(let userId):
        state = AppState.Env(currentUserId: userId)
    }
    
    return state
}

func appReducer(state: AppState = AppState(), action: AppActions) -> AppState {
    var state = state
    
    switch action {
    case .dashAction(let dashAction):
        state.dashState = dashReducer(state: state.dashState, action: dashAction)
    case .envAction(let envAction):
        state.env = envReducer(state: state.env, action: envAction)
    }
    
    return state
}

extension Date {
    static var now: Date {
        return Date(timeIntervalSinceNow: 0)
    }
}

let action: AppActions = .dashAction(.fetchingDash(fetchedAt: .now))
let oldState = AppState()
let newState = appReducer(state: oldState, action: action)

state.swift

struct AppState {
    struct DashState {
        var isFetching: Bool
        var fetchedAt: Date?
        var receivedAt: Date?
        var contents: DashResponse?
    }
    
    struct Env {
        let currentUserId: String
    }
    
    var dashState = DashState(isFetching: false, fetchedAt: nil, receivedAt: nil, contents: nil)
    var env = Env(currentUserId: "asdf1234567890")
}