combineReducers-selective-reset.js

import { combineReducers } from 'redux';
import AppReducer from './AppReducer';

import UsersReducer from './UsersReducer';
import OrderReducer from './OrderReducer';
import NotificationReducer from './NotificationReducer';
import CommentReducer from './CommentReducer';

const appReducer = combineReducers({
  /* your app’s top-level reducers */
  users: UsersReducer,
  orders: OrderReducer,
  notifications: NotificationReducer,
  comment: CommentReducer,
});

const rootReducer = (state, action) => {
  // when a logout action is dispatched it will reset redux state
  if (action.type === 'USER_LOGGED_OUT') {
    // we keep a reference of the keys we want to maintain
    // other keys will be passed as undefined and this will call
    // reducers with an initial state
    const { users, comment } = state;

    state = { users, comment };
  }

  return appReducer(state, action);
};

export default rootReducer;