Support for Redux v5 and RTK v2 about redux-persist

[EskiMojo14]

A more detailed explanation of the change for context:

Prior to Redux v5, the handling for preloadedState was a little hacky. There was only the one State type parameter for reducers, and it was assumed that in most cases preloadedState would just be this State type. However, the most common exception to this was the reducer created by combineReducers, which would accept Partial<State>.

For a long time this was handled by a special $CombinedState brand, which would tell createStore (and configureStore) that it was allowed to have a partial preloadedState instead. This was unintuitive, and had some user-reported issues.

In v5, we took the opportunity to rethink how preloadedState was handled. In practicality, preloadedState is anything that's valid to pass as the first parameter to your reducer, as long as the reducer still returns its normal State. Following this logic, we added an optional third PreloadedState type parameter to the Reducer type (which defaults to State), which appears in the first parameter of the reducer but not the return type.

type Reducer<S, A extends Action = Action, P = S> = (state: S | P | undefined, action: A) => S

This means that the result of combineReducers is now Reducer<State, Action, Partial<State>>.

However when you pass it to persistReducer, it doesn't know to preserve the PreloadedState type parameter, so you end up with Reducer<State, Action> - and suddenly preloadedState is no longer allowed to be partial.

Users can fix this themselves by adding an overload that knows to preserve PreloadedState:

import type { Action, Reducer } from "redux";
import type { PersistConfig, PersistState } from "redux-persist";

declare module "redux-persist" {
  export function persistReducer<S, A extends Action = Action, P = S>(
    config: PersistConfig<S>,
    baseReducer: Reducer<S, A, P>,
  ): Reducer<
    S & { _persist: PersistState },
    A,
    P & { _persist?: PersistState }
  >;
}

But it'd obviously be nicer if the library could be updated to handle this itself 🙂

[zvs001]

Update is pretty important. I experience issue that useSelector doesn't make component to rerender on state change.
Issue gone when I downgrade to RTK v1 or drop redux-persist.

[Haschtl]

I also updated to RTK v2 and I'm not having any type-issues. Where did you encounter type errors?

[xsjcTony]

reduxjs/redux-toolkit#3946 (comment)

[phryneas]

You probably will also have to override the dependency. You can do so with npm overrides:

in your package.json:

{
  // ...
  "dependencies": {
    "@reduxjs/toolkit": "^2.0.1",
    "react-redux": "^9.0.2",
    "redux-persist": "^6.0.0"
  },
  "overrides": {
    "redux-persist": {
      "redux": "^5.0.0"
    }
  }
}

[xsjcTony]

I guess ">4.0.0" is including v5, at least I didn't encounter any issue when installing dependencies

[phryneas]

@xsjcTony Good point. One of our users had problems with that, but I didn't notice it was using >.

[lucipacurar]

Same issue here: useSelector doesn't trigger rerender and my app is stuck in a weird state.

[EskiMojo14]

could either of you put together a reproduction of the issue?

[zvs001]

Here is store setup example that I have in app.
I don't remember versions. I think @reduxjs/toolkit was 2.0.1 or 2.1.0

Also react-redux to reproduce requires v9+. I downgraded to v8 to fix the issue

store.tsx

import AsyncStorage from '@react-native-async-storage/async-storage'
import { configureStore, ThunkAction } from '@reduxjs/toolkit'
import { shallowEqual, TypedUseSelectorHook, useDispatch, useSelector } from 'react-redux'
import { persistStore, persistReducer, FLUSH, REHYDRATE, PAUSE, PERSIST, PURGE, REGISTER } from 'redux-persist'
import { Action } from './app/actions'
import { middleware } from './middleware'
import AppReducers from './index'

const persistedReducer = persistReducer(
  {
    key: 'root',
    storage: AsyncStorage,
    version: 2,
  },
  AppReducers,
)

export const store = configureStore({
  reducer: persistedReducer,
  middleware: (getDefaultMiddleware) => {
    return getDefaultMiddleware({
      serializableCheck: {
        ignoredActions: [FLUSH, REHYDRATE, PAUSE, PERSIST, PURGE, REGISTER],
      },
    }).concat(middleware)
  },
})

// const sagaMiddleware = createSagaMiddleware()
export const persistor = persistStore(store)

// sagaMiddleware.run(saga)

export default {
  store,
  persistor,
}

export const useAppDispatch = () => useDispatch<ReduxDispatch>()
export const useAppSelector: TypedUseSelectorHook<ReduxState> = (selector) => useSelector(selector, shallowEqual)

/* Types */
export type ReduxStore = typeof store
export type ReduxState = ReturnType<typeof AppReducers>
export type ReduxDispatch = typeof store.dispatch
export type ReduxThunkAction<ReturnType = void> = ThunkAction<ReturnType, ReduxState, unknown, Action>

slice.ts

import { createSlice, PayloadAction } from '@reduxjs/toolkit'

interface State {
  deviceLocale: string
  appLocale: string
}

const initialState: State = {
  deviceLocale: '',
  appLocale: '',
}

const slice = createSlice({
  name: 'SYSTEM',
  initialState,
  reducers: {
    setLocale(state, action: PayloadAction<Pick<State, 'appLocale' | 'deviceLocale'>>) {
      const { appLocale, deviceLocale } = action.payload
      state.appLocale = appLocale
      state.deviceLocale = deviceLocale
    },
  },
})

export const { reducer, actions } = slice
export default reducer