Series of posts about building Redux-like Single Source of Truth in SwiftUI.

Single source of truth eliminates tons of bugs produced by creating multiple states across the app. The main idea here is describing the whole app state by using a single struct or composition of structs. A single state for the whole app makes it easier to debug and inspect.

• Redux-like state container in SwiftUI. Basics.
• Redux-like state container in SwiftUI. Best practices.
• Redux-like state container in SwiftUI. Container Views.

import Foundation
import Combine

typealias Reducer<State, Action, Environment> =
    (inout State, Action, Environment) -> AnyPublisher<Action, Never>?

final class Store<State, Action, Environment>: ObservableObject {
    @Published private(set) var state: State

    private let environment: Environment
    private let reducer: Reducer<State, Action, Environment>
    private var effectCancellables: Set<AnyCancellable> = []

    init(
        initialState: State,
        reducer: @escaping Reducer<State, Action, Environment>,
        environment: Environment
    ) {
        self.state = initialState
        self.reducer = reducer
        self.environment = environment
    }

    func send(_ action: Action) {
        guard let effect = reducer(&state, action, environment) else {
            return
        }
        
        effect
            .receive(on: DispatchQueue.main)
            .sink(receiveValue: send)
            .store(in: &effectCancellables)
    }
}