Concurrent API Calls with Promise.all

async function fetchMultipleResources(urls) {
  if (!Array.isArray(urls) || urls.length === 0) {
    console.warn('No URLs provided for concurrent fetching.');
    return [];
  }

  const fetchPromises = urls.map(url =>
    fetch(url)
      .then(response => {
        if (!response.ok) {
          throw new Error(`HTTP error! status: ${response.status} for ${url}`);
        }
        return response.json(); // Assuming JSON response
      })
      .catch(error => {
        console.error(`Error fetching ${url}:`, error);
        return null; // Return null or re-throw based on desired error handling
      })
  );

  try {
    const results = await Promise.all(fetchPromises);
    console.log('All requests completed.');
    // Filter out any failed requests (if they returned null)
    return results.filter(result => result !== null);
  } catch (overallError) {
    // This catch block will only execute if Promise.all rejects immediately,
    // which happens if any of the *individual* promises *rejects* without a catch.
    // Since we added .catch to individual promises, this block might not fire unless new errors are introduced.
    console.error('An unexpected error occurred during Promise.all:', overallError);
    return [];
  }
}

// Example Usage:
(async () => {
  const apiEndpoints = [
    'https://jsonplaceholder.typicode.com/posts/1',
    'https://jsonplaceholder.typicode.com/users/1',
    'https://jsonplaceholder.typicode.com/comments/1',
    'https://api.example.com/non-existent-resource' // Simulate a failing endpoint
  ];

  console.time('Concurrent Fetches');
  const allData = await fetchMultipleResources(apiEndpoints);
  console.timeEnd('Concurrent Fetches');

  if (allData.length > 0) {
    console.log('Fetched data:', allData);
    // Process allData: allData[0] is from posts/1, allData[1] from users/1, etc.
    console.log('Post:', allData[0]);
    console.log('User:', allData[1]);
  } else {
    console.log('No data fetched successfully.');
  }
})();