posts-selector.js

export function getPosts(state) {
  const currentFilter = state.posts.currentFilter;
  const postsById = state.posts.postsById;
  const postsIdArray = currentFilter === 'all' ?
    _.keys(postsById) :
    _.filter(_.keys(postsById), (postId) => postsById[postId].topicUrl === currentFilter);
  return [postsById, postsIdArray];
}