function filterBookPromise(colorful, amountOfPage) {
  return new Promise(function (resolve, reject) {
    var books = [
      { name: "shinchan", totalPage: 50, isColorful: true },
      { name: "kalkulus", totalPage: 250, isColorful: false },
      { name: "doraemon", totalPage: 40, isColorful: true },
      { name: "algoritma", totalPage: 250, isColorful: false },
    ];
    if (amountOfPage >= 40) {
      resolve(
        books.filter(
          (x) => x.totalPage >= amountOfPage && x.isColorful == colorful
        )
      );
    } else {
      var reason = "Maaf buku dibawah 40 halaman tidak tersedia";
      reject(reason);
    }
  });
}

async function example(colorful, totalPage) {
  try {
    const result = await filterBookPromise(colorful, totalPage);
    console.log(result);
  } catch (error) {
    console.error(error);
  }
}
example(true, 40);
example(false, 250);
example(true, 30);