Example.js

// get books
const getBookByName = (name) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({ name: 'Art of War', author: 'Sun Tsu', ISBN: 9780140439199 });
    }, 500);
  });
};

// check if that book exists
checkIfBookExists = (ISBN) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({ stock: 10, ISBN: 9780140439199 });
    }, 500);
  });
};

// hit BooksRun API - To get the new, used and rent price
getTheBookPrice = (ISBN) => {
  return new Promise((resolve, reject) => {
    const URL = `https://booksrun.com/api/v3/price/buy/${ISBN}?key=${process.env.API_KEY}`;

    fetch(URL)
      .then((response) => {
        resolve(response.json());
      })
      .catch((err) => {
        reject(err);
      });
  });
};

// Using Promise
getBookByName('Art of War').then((book) => {
  if (book) {
    checkIfBookExists(book.ISBN).then((data) => {
      if (data.stock > 0) {
        getTheBookPrice(data.ISBN).then((response) => {
          console.log(response);
        });
      }
    });
  } else {
    console.log('Book not found!');
  }
});

// Using async/await
const beingAsync = async () => {
  const book = await getBookByName('Art of War');
  const { stock } = await checkIfBookExists(book.ISBN);

  if (stock > 0) {
    const response = getTheBookPrice(book.ISBN);
    console.log(`Book price is $${response.offers.booksrun.new.price}!`);
  } else {
    console.log('Book not found!');
  }
};

beingAsync();