script.js

const library = [
  { 
    title: "The Great Gatsby", 
    author: "F. Scott Fitzgerald", 
    year: 1925,
    pages: 180 
  },
  {
    title: "To Kill a Mockingbird",
    author: "Harper Lee", 
    year: 1960, 
    pages: 281
  },
  {
    title: "1984", 
    author: "George Orwell", 
    year: 1949, 
    pages: 328 
  },
  {
    title: "Prideand Prejudice", 
    author: "Jane Austen", 
    year: 1813,
    pages: 432 
  }
];

// Total Number of Pages-> This function uses the "reduce" higher-order function 
// It starts with an initial value of 0 and iterates through each book in the library array, adding the pages property of each book to the accumulator.
const getTotalPages = () => library.reduce((total, book) => total + book.pages, 0);
console.log("Total Number of Pages:", getTotalPages());

// List of Book Titles -> For each book in the library array, the "map" function extracts the title property and adds it to the new array.
const getBookTitles = () => library.map(book => book.title);
console.log("List of Book Titles:", getBookTitles());

// Books Published After a Given Year -> This function takes a year parameter and filters the library array using the filter higher-order function.
//The "filter" function checks if the year property of each book is greater than the input year, and only includes those books in the result.
const getBooksPublishedAfterYear = year => library.filter(book => book.year > year).map(book => book.title);
console.log("Books Published After 1950:", getBooksPublishedAfterYear(1950));

// Average Number of Pages -> This function divides the total number of pages (calculated using getTotalPages()) by the number of books in the library.
const getAveragePages = () => getTotalPages() / library.length;
console.log("Average Number of Pages:", getAveragePages());

// Longest Book -> It iterates through each book in the library array, comparing the pages property of each book to the current longest book.
const getLongestBook = () => library.reduce((longestBook, book) => book.pages > longestBook.pages ? book : longestBook);
console.log("Longest Book:", getLongestBook().title);

// Authors and Their Books -> It iterates through each book in the library array and adds the book title to the corresponding author's array in the authorsAndBooks object.
const getAuthorsAndBooks = () => {
  const authorsAndBooks = {};
  library.forEach(book => {
    if (!authorsAndBooks[book.author]) {
      authorsAndBooks[book.author] = [];
    }
    authorsAndBooks[book.author].push(book.title);
  });
  return authorsAndBooks;
};
console.log("Authors and Their Books:", getAuthorsAndBooks());

// Total Number of Pages by Author -> It iterates through each book in the library array and adds the book's pages to the corresponding author's total pages in the totalPagesByAuthor object.
const getTotalPagesByAuthor = () => {
  const totalPagesByAuthor = {};
  library.forEach(book => {
    if (!totalPagesByAuthor[book.author]) {
      totalPagesByAuthor[book.author] = 0;
    }
    totalPagesByAuthor[book.author] += book.pages;
  });
  return totalPagesByAuthor;
};
console.log("Total Number of Pages by Author:", getTotalPagesByAuthor());

// Shortest Book by Author -> It iterates through each book in the library array and checks if the current book has fewer pages than the current shortest book for that author.
const getShortestBookByAuthor = () => {
  const shortestBookByAuthor = {};
  library.forEach(book => {
    if (!shortestBookByAuthor[book.author] || book.pages < shortestBookByAuthor[book.author].pages) {
      shortestBookByAuthor[book.author] = book;
    }
  });
  return shortestBookByAuthor;
};
console.log("Shortest Book by Author:", getShortestBookByAuthor());
const library1 = [
    {
      title: "The Great Gatsby",
      author: "F. Scott Fitzgerald",
      year: 1925,
      pages: 180,
    },
    {
      title: "To Kill a Mockingbird",
      author: "Harper Lee",
      year: 1960,
      pages: 281,
    },
    {
      title: "1984",
      author: "George Orwell",
      year: 1949,
      pages: 328,
    },
    {
      title: "Pride and Prejudice",
      author: "Jane Austen",
      year: 1813,
      pages: 432,
    },
  ];

  // Function to calculate and return the total number of pages in the library
  function getTotalPage(library) {
    return library.reduce((total, book) => total + book.pages, 0);
  }

  // Function to get an array containing only the titles of the books
  function getBookTitle(library) {
    return library.map((book) => book.title);
  }

  // Function to get an array of book titles published after a given year
  function getBookPublishedAfterYear(library, year) {
    return library
      .filter((book) => book.year > year)
      .map((book) => book.title);
  }

  // Function to calculate and return the average number of pages
  function getAveragePage(library) {
    const totalPages = getTotalPages(library);
    return totalPages / library.length;
  }

  // Function to get the title of the book with the most pages
  function getLongestbook(library) {
    const longestBook = library.reduce((prev, current) =>
      prev.pages > current.pages ? prev : current
    );
    return longestBook.title;
  }

  // Function to get an object where keys are author names and values are arrays of book titles
  function getAuthorsAndBook(library) {
    return library.reduce((result, book) => {
      if (!result[book.author]) {
        result[book.author] = [];
      }
      result[book.author].push(book.title);
      return result;
    }, {});
  }

  // Function to get an object where keys are author names and values are total pages written by each author
  function getTotalPageByAuthor(library) {
    return library.reduce((result, book) => {
      if (!result[book.author]) {
        result[book.author] = 0;
      }
      result[book.author] += book.pages;
      return result;
    }, {});
  }

  // Function to get an object where keys are author names and values are titles of shortest books
  function getShortestBookbyAuthor(library) {
    return library.reduce((result, book) => {
      if (!result[book.author] || result[book.author].pages > book.pages) {
        result[book.author] = book;
      }
      return result;
    }, {});
  }

  // Testing the functions
  console.log("Total Number of Pages:", getTotalPages(library));
  console.log("Book Titles:", getBookTitles(library));
  console.log("Books Published After 1900:", getBooksPublishedAfterYear(library, 1900));
  console.log("Average Number of Pages:", getAveragePages(library));
  console.log("Longest Book:", getLongestBook(library));
  console.log("Authors and Their Books:", getAuthorsAndBooks(library));
  console.log("Total Number of Pages by Author:", getTotalPagesByAuthor(library));
  console.log("Shortest Book by Author:", getShortestBookByAuthor(library));