Hot reloadable redux-saga ... sagas

configureStore.js

import { applyMiddleware, createStore } from 'redux';
import createSagaMiddleware from 'redux-saga';
import rootReducer from './rootReducer';
import SagaManager from './SagaManager';

export default function configureStore (initialState = {}) {
    // create saga middleware
    const sagaMiddleware = createSagaMiddleware();

    // create middleware function, which contains all normal
    let middleware = applyMiddleware(sagaMiddleware);

    // Create final store and subscribe router in debug env ie. for devtools
    const store = middleware(createStore)(rootReducer, initialState);

    // run sagas
    SagaManager.startSagas(sagaMiddleware);

    // enable hot module reloading for reducers
    if (module.hot) {
        module.hot.accept('./rootReducer', () => {
            store.replaceReducer(require('./rootReducer').default);
        });
        module.hot.accept('./SagaManager', () => {
            SagaManager.cancelSagas(store);
            require('./SagaManager').default.startSagas(sagaMiddleware);
        });
    }

    return store;
}

SagaManager.js

import mySaga from 'mySaga';
import { take, fork, cancel } from 'redux-saga/effects';

const sagas = [mySaga];

export const CANCEL_SAGAS_HMR = 'CANCEL_SAGAS_HMR';

function createAbortableSaga (saga) {
    if (process.env.NODE_ENV === 'development') {
        return function* main () {
            const sagaTask = yield fork(saga);

            yield take(CANCEL_SAGAS_HMR);
            yield cancel(sagaTask);
        };
    } else {
        return saga;
    }
}

const SagaManager = {
    startSagas(sagaMiddleware) {
        sagas.map(createAbortableSaga).forEach((saga) => sagaMiddleware.run(saga));
    },

    cancelSagas(store) {
        store.dispatch({
            type: CANCEL_SAGAS_HMR
        });
    }
};

export default SagaManager;

See this issue for more context and potential problems.