Client-Side Utility for Batching Parallel API Requests

async function batchParallelRequests(requestConfigs) {
  const fetchPromises = requestConfigs.map(config => {
    const { url, method = 'GET', body, headers } = config;
    const options = {
      method,
      headers: { 'Content-Type': 'application/json', ...headers }
    };
    if (body && (method === 'POST' || method === 'PUT')) {
      options.body = JSON.stringify(body);
    }
    return fetch(url, options)
      .then(response => {
        if (!response.ok) {
          return response.json().then(errorData => {
            throw new Error(`HTTP ${response.status}: ${JSON.stringify(errorData)}`);
          }).catch(() => {
            throw new Error(`HTTP ${response.status} for ${url}`);
          });
        }
        return response.json();
      })
      .catch(error => ({
        url, 
        status: 'failed', 
        error: error.message || 'Network error'
      })); // Gracefully handle individual request failures
  });

  // Wait for all promises to settle (either fulfilled or rejected)
  const results = await Promise.allSettled(fetchPromises);

  // Process results to separate successful and failed ones
  const formattedResults = results.map((result, index) => {
    if (result.status === 'fulfilled') {
      return { url: requestConfigs[index].url, status: 'success', data: result.value };
    } else {
      // For Promise.allSettled, result.reason is the error thrown by the promise
      return { url: requestConfigs[index].url, status: 'failed', error: result.reason.error || result.reason.message || 'Unknown error' };
    }
  });

  return formattedResults;
}

// Example usage:
// const requests = [
//   { url: 'https://jsonplaceholder.typicode.com/todos/1' },
//   { url: 'https://jsonplaceholder.typicode.com/users/1' },
//   { url: 'https://jsonplaceholder.typicode.com/non-existent-endpoint' } // Simulate a failed request
// ];

// batchParallelRequests(requests)
//   .then(allResults => {
//     console.log('Batch results:', allResults);
//     // You can then filter or process allResults
//   })
//   .catch(error => console.error('Batch error:', error));