app\static\js\middleware(1).jsx

const promiseMiddleware = store => next => action => {
    if (isPromise(action.payload)) {
        store.dispatch({type: 'ASYNC_START', subtype: action.type});
        action.payload.then(
            res => {
                action.payload = res;
                store.dispatch(action);
            },
            error => {
                action.error = true;
                action.payload = error.response.body;
                store.dispatch(action);
            }
        );

        return;
    }
    next(action);
};

function isPromise(v) {
    return v && typeof v.then === 'function';
}

const localStorageMiddleware = store => next => action => {
    if (action.type === 'REGISTER' || action.type === 'LOGIN') {
        if (!action.error) {
            window.localStorage.setItem('currentUser', action.payload.user);
            store.redirectTo = '/'
        }
    } else if (action.type === 'LOGOUT') {
        window.localStorage.setItem('currentUser', '');
    }

    next(action);
};

export {
    localStorageMiddleware,
    promiseMiddleware
}