store.js

import createSagaMiddleware from 'redux-saga';

// code

// root reducer
import rootReducer from './rootReducer';

// root saga
import rootSaga from './rootSaga';

// code 

// create the store
const sagaMiddleware = createSagaMiddleware(); 
const configureStore = () => {
  const store = {
    ...createStore(rootReducer, composeEnhancers(
      applyMiddleware(sagaMiddleware)))
  };
    
  sagaMiddleware.run(rootSaga);
  
  return store;
};