invalidation_coordinator 0.1.0

invalidation_coordinator: ^0.1.0 copied to clipboard

example/invalidation_coordinator_example.dart

import 'dart:async';

import 'package:invalidation_coordinator/invalidation_coordinator.dart';

enum Resource { profile, inbox, transactions }

Future<void> main() async {
  final firstRefreshStarted = Completer<void>();
  var invocation = 0;

  final coordinator = InvalidationCoordinator<Resource>(
    handler: (resources) async {
      invocation++;
      print('Batch $invocation: ${_names(resources)}');
      if (invocation == 1) firstRefreshStarted.complete();
      await _refresh(resources);
    },
    onError: (resources, error, stackTrace) {
      print('Refresh failed for ${_names(resources)}: $error');
    },
  );

  // Duplicate profile signals collapse into the first snapshot.
  coordinator.invalidate(Resource.profile);
  coordinator.invalidateAll([Resource.inbox, Resource.profile]);

  await firstRefreshStarted.future;

  // These arrive while the first batch is running. They become one trailing
  // snapshot; profile is eligible again because its earlier attempt is active.
  coordinator.invalidate(Resource.profile);
  coordinator.invalidateAll([Resource.transactions, Resource.profile]);

  await coordinator.idle;
  print('All accepted refresh work is idle.');

  await coordinator.close();
  print('Coordinator closed.');
}

Future<void> _refresh(Set<Resource> resources) async {
  // Replace this delay with application-specific API or database work.
  await Future<void>.delayed(const Duration(milliseconds: 20));
}

String _names(Set<Resource> resources) {
  final names = resources.map((resource) => resource.name).toList()..sort();
  return names.join(', ');
}