[Vuejs]-Errors: "[Vue warn]: Property or method "posts" is not defined on the instance but referenced during render." and also for "books"

export default {

  components: {
    InstanceHeader,
    BooksInfoPostTop,
    BookTitles,
    BooksInfoPost
  },

  async asyncData(context) {
    const result = {};
    const mapBooks = b => {
      return {
        id: b.slug,
        bookCover: b.content.bookCover,
        title: b.content.title,
        author: b.content.author
      };
    };

    const { data } = await context.app.$storyapi
      .get("cdn/stories", {
        version: "draft",
        starts_with: 'books/book-titles'
      });

    result.posts = data.stories.map(mapBooks);

    const result = await context.app.$storyapi
      .get("cdn/stories", {
        version: "draft",
        starts_with: 'books/top-books'
      });

    result.books = result.data.stories.map(mapBooks);

    return result; // it has right property names {books:[], posts:[]}
  }
}