// which is better

// For each case, read code from bottom to top

// CASE 1
// less refactoring, but fn's aren't necessarily following DO ONE THING
const searchResultsDiffer = (searchResults, kvs) =>
  searchResults.map(
    book =>
      kvs[book.id]
        ? kvs[book.id]
        : book.shelf ? { ...book, shelf: false } : book
  );

const SearchViewDiffer = (nextProps, prevState) => {
  return {
    query: prevState.query,
    searchResults: searchResultsDiffer(
      prevState.searchResults,
      nextProps.shelfKeyValueStore
    )
  };
};
//---------------------------------------------------------------------

// CASE 2
// fn's do less, but more code
const returnFormattedBook = book => ({ ...book, shelf: false });

const bookShelfChecker = book =>
  book.shelf ? returnFormattedBook(book) : book;

const bookRecordExists = (kvs, book) => (kvs[book.id] ? true : false);

const searchResultsDiffer = (searchResults, kvs) =>
  searchResults.map(
    book =>
      bookRecordExists(kvs, book) ? kvs[book.id] : bookShelfChecker(book)
  );

const SearchViewDiffer = (nextProps, prevState) => ({
  query: prevState.query,
  searchResults: searchResultsDiffer(
    prevState.searchResults,
    nextProps.shelfKeyValueStore
  )
});