Concurrent Asynchronous Operations in Dart: A Guide to Future.wait link: https://www.linkedin.com/pulse/concurrent-asynchronous-operations-dart-guide-sabin-ranabhat-u70nf

main.dart

import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' as http;

void main() async {
  print("Fetching todo data from JSONPlaceholder API using Future.wait method...");

  // Create a list of asynchronous tasks to fetch todo data from different users
  List<Future<Map<String, dynamic>>> apiCalls = [
    fetchTodoData(1),
    fetchTodoData(2),
    fetchTodoData(3),
    fetchTodoData(4),
    fetchTodoData(5),
    fetchTodoData(6),
    fetchTodoData(7),
    fetchTodoData(8),
    fetchTodoData(9),
    fetchTodoData(10),
  ];

  // Measure the time taken for all API calls to complete using Future.wait
  Stopwatch stopwatch = Stopwatch()..start();

  try {
    // Use Future.wait to wait for all API calls to complete
    List<Map<String, dynamic>> results = await Future.wait(apiCalls);

    // Log the results
    for (int i = 0; i < results.length; i++) {
      print("Todo data for user $i: ${jsonEncode(results[i])}");
    }

    // Stop the stopwatch
    stopwatch.stop();
    
    print("All API calls completed in ${stopwatch.elapsedMilliseconds} ms");
  } catch (error) {
    // Handle error: will be executed if any async function returns error
    print("Error occurred: $error");    
  }
}

Future<Map<String, dynamic>> fetchTodoData(int todoId) async {
  // Fetching todo data from the JSONPlaceholder API
  final response = await http.get(Uri.parse('https://jsonplaceholder.typicode.com/todos/$todoId'));

  if (response.statusCode == 200) {
    return jsonDecode(response.body);
  } else {
    throw Exception('Failed to fetch todo data for user $todoId');
  }
}

Future<void> cleanUpResources() async {
  // Implement cleanup logic, e.g., closing files or DB, releasing connections, etc.
  print("Performing cleanup of resources...");
}