+(_:_:)

public func +<R1: Reducer, R2: Reducer>(lhs: R1, rhs: R2) -> CombinedReducer

Combines two reducers. The combined reducer calls each of its internal reducer for a each paricular state key.

Example

Combine reducers

If your application has two screens, you can model that with two states, for example TodoList and Settings states. We can then create two reducers for each of these states.

let todoReducer = BlockReducer(state: TodoList.self) { state, action in
  guard let newState = state as? Int else { return state }

  if action is SomeAction {
    return newState + 1
  }

  return newState
}

let settingsReducer = BlockReducer(state: Settings.self) { state, action in
  guard let newState = state as? Int else { return state }

  if action is SomeAction {
    return newState + 1
  }

  return newState
}

We can then combine these 2 reducers with:

let store = Suas.createStore(
  reducer: todoReducer + settingsReducer
)

todoReducer will handle the TodoList key of state and settingsReducer will handle the Settings portoon of the full Store state

Combine reducers with custom state key

If a store has a state with two keys key1 and key2. We can register a reducer for each one of these keys.

We create two reducers with stateKeys of key1 and key2

let myReducer1 = BlockReducer(state: 1, key: "key1") { state, action in
  guard let newState = state as? Int else { return state }

  if action is SomeAction {
    return newState + 1
  }

  return newState
}

let myReducer2 = BlockReducer(state: 1, key: "key2") { state, action in
  guard let newState = state as? Int else { return state }

  if action is SomeAction {
    return newState + 1
  }

  return newState
}

We can then combine these 2 reducers with:

let store = Suas.createStore(
  reducer: myReducer1 + myReducer2
)

myReducer1 will handle the key1 key of state and myReducer2 will handle the key2 key of state