Riverpod — ProviderObservers

Instructions

A ProviderObserver receives lifecycle events for providers (e.g. when a provider's value changes). Use it for logging, analytics, or debugging.

Implementing an observer

Extend ProviderObserver and override the methods you need (e.g. didUpdateProvider). Pass instances to ProviderScope or ProviderContainer via the

observers

parameter.

Example: logger

final class Logger extends ProviderObserver {
  @override
  void didUpdateProvider(
    ProviderObserverContext context,
    Object? previousValue,
    Object? newValue,
  ) {
    print('{"provider": "${context.provider}", "newValue": "$newValue"}');
  }
}

void main() {
  runApp(
    ProviderScope(
      observers: [Logger()],
      child: const MyApp(),
    ),
  );
}

Naming providers

For clearer logs, give providers a name:

final myProvider = Provider<int>((ref) => 0, name: 'MyProvider');

With code generation, a name is usually assigned automatically.

Note on mutations

If state is mutated in place (e.g. a List with ref.notifyListeners),

previousValue

and

newValue

in didUpdateProvider may be the same reference. For distinct values, clone before mutating.