function getArticleVector(action$, state$) {
    return action$.pipe(
        ofType(actions.setArticle.type),
        switchMap(({ payload }) => {
            if (!payload) {
                return EMPTY;
            }
            return api.analyzeArticle(payload)
                .pipe(
                    map(data => actions.setArticleVector(data.response.vector)),
                );
        }),
        setError(),
    );
}