Youtube selectors: video categories loaded and videos by category loaded

videos.js

export const videoCategoriesLoaded = createSelector(
  state => state.videos.categories,
  (categories) => {
    return Object.keys(categories || {}).length !== 0;
  }
);

export const videosByCategoryLoaded = createSelector(
  state => state.videos.byCategory,
  (videosByCategory) => {
    return Object.keys(videosByCategory || {}).length;
  }
);