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),
                        actions.setArticleLang(data.response.lang),
                    ]),
                    flatMap(action => action),
                );
        }),
        setError(),
    );
}