Vyuh

Feature flags ​

Features read rollout decisions through FeatureFlagPlugin. The app chooses its backend implementation and registers it in PluginDescriptor.others.

How the pieces fit together

Evaluate a flag in code ​

dart
import 'package:vyuh_core/vyuh_core.dart';

Future<bool> showNewCheckout() async {
  final flags = vyuh.featureFlag;
  if (flags == null) return false;
  return flags.getBool('checkout.new', defaultValue: false);
}

The contract also provides getString, getInt, getDouble, and getJson. Use setDefaults for fallback values, updateContext for implementation-specific evaluation context, and refresh to request updated decisions. Await evaluation and handle provider failures according to your app’s fallback policy.

Gate lazy activation ​

Set LazyFeatureDescriptor.featureFlag to the flag name. The runtime checks it before loading the feature. The current runtime uses defaultValue: true for this check and permits loading when no flag plugin is configured. Configure a provider explicitly when rollout gating is required.

Feature flag evaluation is asynchronous. Evaluate before choosing a branch or updating observable state; the framework does not automatically rebuild a widget whenever a remote flag changes.

Keep authorization separate ​

Flags control rollout and presentation. Enforce access permissions in the backend even when a screen is hidden. Test enabled, disabled, absent-provider, and provider-failure behavior.

See FeatureFlagPlugin APIs and lazy feature APIs.