book shelf - fundamentals

function bookShelf(input) {
  let shelvesList = new Map();
  let bookList = new Map();
  for (const line of input) {
    if (line.includes(" -> ")) {
      let [id, type] = line.split(" -> ");
      if (!shelvesList.has(type)) {
        let temp = [...shelvesList.values()];
        if (!temp.includes(id)) {
          shelvesList.set(type, id);
        }
      }
    } else if (line.includes(": ")) {
      let [bookTitle, rest] = line.split(": ");
      let [bookAuthor, genre] = rest.split(", ");
      let curShelves = [...shelvesList.keys()];
      if (curShelves.includes(genre)) {
        if (!bookList.has(genre)) {
          bookList.set(genre, [
            { bookTitle: bookTitle, bookAuthor: bookAuthor },
          ]);
        } else {
          let currBookList = bookList.get(genre);
          currBookList.push({ bookTitle: bookTitle, bookAuthor: bookAuthor });
          bookList.set(genre, currBookList);
        }
      }
    }
  }

  [...bookList.entries()]
    .sort((a, b) => b[1].length - a[1].length)
    .forEach((shelf) => {
      let [genre, books] = shelf;
      books.sort((a, b) => a.bookTitle.localeCompare(b.bookTitle));
      console.log(`${shelvesList.get(genre)} ${genre}: ${books.length}`);
      for (const book of books) {
        console.log(`--> ${book.bookTitle}: ${book.bookAuthor}`);
      }
    });
}