CombineReducers() defines, but state is always undefined - redux

Question

I did use combineReducers() and the initialState is defined in each reducer separately.
The issue is:
-> the state seem to be always undefined, even within the reducer, I tried to console.log({...state}) and I get an empty object.
When I replace state with initialState in each return{} then I get the initialState data.
I tried in the clientsReducer function the following:
1- state = {...initialState} => gives an empty object
2- remove the initialState from the args and do the assignment inside the function. => gives undefined
any idea why?
const initialState = {
clientsArray: [],
shouldFetchClients: false,
isFetchingClients: false,
fetchClientsError: null,
};
export default function clientsReducer(state = initialState, action) {
switch (action.type) {
case FETCH_CLIENTS_SUCCESS:
return {
...state,
clientsArray: action.payload,
isFetchingClients: false,
};
case FETCH_CLIENTS_FAILURE:
return {
...state,
fetchClientsError: action.payload,
isFetchingClients: false,
};
case FETCH_CLIENTS:
return {
...state,
isFetchingClients: true,
shouldFetchClients: true,
clientsArray: null,
};
default:
return state;
}
}
This is a reducer's code, and I am using combineReducers function to define the RootReducer :
import { combineReducers } from 'redux';
//REDUCER FILES IMPORTS HERE
export default combineReducers({
clients: clientsReducer,
admins: adminsReducer
})
then, in createStore I have:
import { createStore, applyMiddleware, compose } from 'redux';
import thunk from 'redux-thunk';
import { persistReducer, persistStore } from 'redux-persist';
import createSagaMiddleware from 'redux-saga';
import storage from 'redux-persist/lib/storage';
import createFilter from 'redux-persist-transform-filter';
// CONNECTED-REACT-ROUTER
import { createBrowserHistory } from 'history';
import { routerMiddleware, connectRouter } from 'connected-react-router';
import rootReducer from './rootReducer';
export const history = createBrowserHistory();
const sagaMiddleware = createSagaMiddleware();
const persistedReducer = persistReducer(persistConfig, rootReducer);
export const store = createStore(
connectRouter(history)(persistedReducer),
composeEnhancer(
applyMiddleware(
routerMiddleware(history),
sagaMiddleware,
thunk,
createLogService(true),
),
),
);