reactjs - How to reset state of Redux Store when using configureStore from @reduxjs/toolkit?

Question

I have seen solutions for clearing/resetting the store after logout but did not understand how to implement the same functionality for the following way of setting up the redux store.

Store.js:

import { configureStore, getDefaultMiddleware } from '@reduxjs/toolkit'
import authReducer from './ducks/authentication'
import snackbar from './ducks/snackbar'
import sidebar from './ducks/sidebar'
import global from './ducks/global'
import quickView from './ducks/quickView'
import profileView from './ducks/profileView'

const store = configureStore({
  reducer: {
    auth: authReducer,
    snackbar,
    sidebar,
    global,
    quickView,
    profileView,
  },
  middleware: [...getDefaultMiddleware()],
})

export default store

Here is how all the reducers implemented using createAction and createReducer from @reduxjs/toolkit.

snackbar.js:

import { createAction, createReducer } from '@reduxjs/toolkit'

export const handleSnackbar = createAction('snackbar/handleSnackbar')

export const openSnackBar = (
  verticalPosition,
  horizontalPosition,
  message,
  messageType,
  autoHideDuration = 10000
) => {
  return async dispatch => {
    dispatch(
      handleSnackbar({
        verticalPosition,
        horizontalPosition,
        message,
        autoHideDuration,
        messageType,
        isOpen: true,
      })
    )
  }
}

export const closeSnackbar = () => {
  return dispatch => {
    dispatch(handleSnackbar({ isOpen: false }))
  }
}

const initialState = {
  verticalPosition: 'bottom',
  horizontalPosition: 'center',
  message: '',
  autoHideDuration: 6000,
  isOpen: false,
  messageType: 'success',
}

export default createReducer(initialState, {
  [handleSnackbar]: (state, action) => {
    const {
      isOpen,
      verticalPosition,
      horizontalPosition,
      message,
      autoHideDuration,
      messageType,
    } = action.payload
    state.isOpen = isOpen
    state.verticalPosition = verticalPosition
    state.horizontalPosition = horizontalPosition
    state.message = message
    state.autoHideDuration = autoHideDuration
    state.messageType = messageType
  },
})

Answer 1

As per Dan Abramov's answer, create a root reducer which will simply delegate the action to your main or combined reducer. And whenever this root reducer receives a reset type of action, it resets the state.

Example:

const combinedReducer = combineReducers({
  first: firstReducer,
  second: secondReducer,
  // ... all your app's reducers
})

const rootReducer = (state, action) => {
  if (action.type === 'RESET') {
    state = undefined
  }
  return combinedReducer(state, action)
}

So, if you have configured your store with @reduxjs/toolkit's configureStore, it might look like this:

import { configureStore } from '@reduxjs/toolkit';
import counterReducer from '../features/counter/counterSlice';

export default configureStore({
  reducer: {
    counter: counterReducer,
    // ... more reducers
  },
});

where configureStore's first parameter reducer accepts a function (which is treated as root reducer) or an object of slice reducers which is internally converted to root reducer using combineReducers.

So, now instead of passing object of slice reducers (shown above), we can create and pass root reducer by ourselves, here is how we can do it:

const combinedReducer = combineReducers({
  counter: counterReducer,
  // ... more reducers
});

Now, lets create a root reducer which does our reset job when needed:

const rootReducer = (state, action) => {
  if (action.type === 'counter/logout') { // check for action type 
    state = undefined;
  }
  return combinedReducer(state, action);
};

export default configureStore({
  reducer: rootReducer,
  middleware: [...getDefaultMiddleware()]
});

Here is CodeSandbox