Perform Concurrent API Requests with Batching

const axios = require('axios'); // For making HTTP requests

async function fetchMultipleResourcesConcurrently(resourceIds) {
    const BASE_URL = 'https://jsonplaceholder.typicode.com/posts/'; // Example API
    const requests = resourceIds.map(id =>
        axios.get(`${BASE_URL}${id}`)
            .then(response => ({ id, status: response.status, data: response.data }))
            .catch(error => ({ id, status: error.response ? error.response.status : 'N/A', error: error.message }))
    );

    console.log(`Attempting to fetch ${resourceIds.length} resources concurrently...`);

    try {
        const results = await Promise.all(requests);
        console.log('All concurrent requests completed.');
        return results;
    } catch (error) {
        // This catch block would typically only be hit if Promise.all fails fast
        // due to a severe error before all promises settle.
        // With the individual .catch() on each request, Promise.all usually waits for all to settle.
        console.error('An unexpected error occurred during concurrent fetching:', error.message);
        throw error;
    }
}

// --- Example Usage ---
(async () => {
    const idsToFetch = [1, 2, 3, 4, 5];
    try {
        const fetchedData = await fetchMultipleResourcesConcurrently(idsToFetch);
        fetchedData.forEach(result => {
            if (result.error) {
                console.error(`Error fetching ID ${result.id}: Status ${result.status}, Error: ${result.error}`);
            } else {
                console.log(`Successfully fetched ID ${result.id}. Title: "${result.data.title.substring(0, 30)}..."`);
            }
        });
    } catch (e) {
        console.error('Main execution failed:', e);
    }

    console.log('
--- Example with a non-existent ID (simulating a 404 error) ---');
    const idsWithError = [10, 9999, 11]; // 9999 will likely return a 404
    try {
        const fetchedDataWithError = await fetchMultipleResourcesConcurrently(idsWithError);
        fetchedDataWithError.forEach(result => {
            if (result.error) {
                console.error(`Error fetching ID ${result.id}: Status ${result.status}, Error: ${result.error}`);
            } else {
                console.log(`Successfully fetched ID ${result.id}. Title: "${result.data.title.substring(0, 30)}..."`);
            }
        });
    } catch (e) {
        console.error('Main execution failed for error example:', e);
    }
})();