app.js

// 1. Import the complete book array from your data file
import catalog from './catalogData.js';

// 2. Group Books by Decade Function
function groupByDecade(catalog) {
  const grouped = {};

  for (let i = 0; i < catalog.length; i++) {
    const book = catalog[i];

    if (book.year === "Unknown") {
      if (!grouped["Unknown"]) {
        grouped["Unknown"] = [];
      }
      grouped["Unknown"].push(book);
      continue;
    }

    const decade = Math.floor(book.year / 10) * 10;
    const decadeKey = `${decade}s`;

    if (!grouped[decadeKey]) {
      grouped[decadeKey] = [];
    }
    grouped[decadeKey].push(book);
  }

  return grouped;
}

// 3. Render Library Card Component Function
function renderEntry(entry) {
  const title = entry.title || "Unknown";
  const author = entry.author || "Unknown";
  const year = entry.year || "Unknown";
  const location = entry.location || "Unknown";

  return `${"-".repeat(25)}
Title: ${title}
Author: ${author}
Year: ${year}
Location: ${location}
${"-".repeat(25)}`;
}

// 4. Data Validation Gatekeeper Function
function validateEntry(entry) {
  let isValid = true;

  if (!entry.title || entry.title === "Unknown") {
    isValid = false;
  }
  if (!entry.author || entry.author === "Unknown") {
    isValid = false;
  }
  if (!entry.year || entry.year === "Unknown") {
    isValid = false;
  }
  if (!entry.location || entry.location === "Unknown") {
    isValid = false;
  }

  return isValid;
}

// 5. CSV Data Exporter Function
function exportToCSV(catalog) {
  const header = "Title,Author,Year,Location";
  const rows = [];

  for (let i = 0; i < catalog.length; i++) {
    const entry = catalog[i];
    rows.push(`"${entry.title}","${entry.author}",${entry.year},"${entry.location}"`);
  }

  let csv = header;
  for (let i = 0; i < rows.length; i++) {
    csv = csv + "\n" + rows[i];
  }

  return csv;
}

// ==========================================
// EXECUTION & TESTING
// ==========================================

console.log("--- 1. TESTING VALIDATION ON FIRST ENTRY ---");
console.log(`Is the first book valid? ${validateEntry(catalog[0])}`);

console.log("\n--- 2. PRINTING FIRST BOOK INDEX CARD ---");
console.log(renderEntry(catalog[0]));

console.log("\n--- 3. BOOKS GROUPED BY DECADE ---");
console.log(groupByDecade(catalog));

console.log("\n--- 4. FINAL CSV EXPORT STRING ---");
console.log(exportToCSV(catalog));