store.js

rootReducer.js

import { combineReducers } from 'redux-immutable';
import rootReducers from 'store/rootReducers';

const rootReducer = { rootReducers };

export const createReducer = asyncReducers => combineReducers({ ...rootReducer, ...asyncReducers });

export default combineReducers(rootReducer);

rootSaga.js

import { all } from 'redux-saga/effects';
import rootSagas from 'store/rootSagas';

const run = sagas => sagas.map(saga => saga());

export default function* rootSaga() {
  yield all([...run(rootSagas)]);
}

store.js

import { createStore, compose, applyMiddleware } from 'redux';
import Immutable from 'immutable';
import createSagaMiddleware from 'redux-saga';
import rootReducer, { createReducer } from 'rootReducer';
import rootSaga from 'rootSaga';

const sagaMiddleware = createSagaMiddleware();

const configureStore = initialState => {
  const store = createStore(
    rootReducer,
    initialState,
    compose(
      applyMiddleware(sagaMiddleware),
      process.env.NODE_ENV === 'development' && window.__REDUX_DEVTOOLS_EXTENSION__
        ? window.__REDUX_DEVTOOLS_EXTENSION__()
        : f => f
    )
  );
  sagaMiddleware.run(rootSaga);
  if (process.env.NODE_ENV === 'development') {
    if (module.hot) {
      module.hot.accept('./rootReducer', () => {
        store.replaceReducer(createReducer(store.asyncReducers));
      });
    }
  }
  store.runSaga = sagaMiddleware.run;
  store.asyncReducers = store.asyncReducers || {};
  store.asyncSagas = store.asyncSagas || [];
  return store;
};

export const injectAsyncReducer = ({ name, asyncReducer, store }) => {
  store.asyncReducers[name] = asyncReducer;
  store.replaceReducer(createReducer(store.asyncReducers));
};

export function injectAsyncSagas({ name, sagas, store }) {
  if (!store.asyncSagas.includes(name)) {
    sagas.forEach(store.runSaga);
    store.asyncSagas.push(name);
  }
}

const initialState = Immutable.Map();
export default configureStore(initialState);