Efficient Concurrent API Calls Using Promise.all

async function fetchMultipleResources(urls, fetchOptions = {}) {
  try {
    const fetchPromises = urls.map(url => 
      fetch(url, fetchOptions).then(response => {
        if (!response.ok) {
          throw new Error(`HTTP error! status: ${response.status} for ${url}`);
        }
        return response.json();
      })
    );

    const results = await Promise.all(fetchPromises);
    return results;
  } catch (error) {
    console.error('Error fetching multiple resources:', error.message);
    throw error; // Re-throw to allow caller to handle
  }
}

// Example Usage:
const API_BASE = 'https://jsonplaceholder.typicode.com'; // A public test API
const resourceUrls = [
  `${API_BASE}/posts/1`,
  `${API_BASE}/users/2`,
  `${API_BASE}/comments?postId=1`,
];

(async () => {
  console.time('Fetch Multiple Resources');
  try {
    const [post, user, comments] = await fetchMultipleResources(resourceUrls);

    console.log('Fetched Post:', post);
    console.log('Fetched User:', user);
    console.log('Fetched Comments (for Post 1):', comments);
  } catch (error) {
    console.error('Failed to fetch all resources:', error.message);
  }
  console.timeEnd('Fetch Multiple Resources');

  // Demonstrate sequential fetching for comparison (slower)
  console.time('Fetch Resources Sequentially');
  try {
    const postSequential = await (await fetch(resourceUrls[0])).json();
    const userSequential = await (await fetch(resourceUrls[1])).json();
    const commentsSequential = await (await fetch(resourceUrls[2])).json();
    // console.log('Sequential Post:', postSequential);
    // console.log('Sequential User:', userSequential);
    // console.log('Sequential Comments:', commentsSequential);
  } catch (error) {
    console.error('Failed to fetch resources sequentially:', error.message);
  }
  console.timeEnd('Fetch Resources Sequentially');
})();