hydrated_bloc library Null safety

An extension to package:bloc which automatically persists and restores bloc and cubit states. Built to work with package:bloc.

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Bloc<Event, State>
Takes a Stream of Events as input and transforms them into a Stream of States as output.
An interface for the core functionality implemented by both Bloc and Cubit.
BlocEventSink<Event extends Object?>
An ErrorSink that supports adding events.
An interface for observing the behavior of Bloc instances.
This class facilitates overriding BlocObserver and EventTransformer. It should be extended by another class in client code with overrides that construct a custom implementation. The implementation in this class defaults to the base blocObserver and eventTransformer implementation. For example:
A Change represents the change from one State to another. A Change consists of the currentState and nextState.
An object that must be closed when no longer in use.
A Cubit is similar to Bloc but has no notion of events and relies on methods to emit new states.
Emittable<State extends Object?>
An object that can emit new states.
An Emitter is a class which is capable of emitting new states.
A generic destination for errors.
Default encryption algorithm. Uses AES256 CBC with PKCS7 padding.
HydratedBloc<Event, State>
Specialized Bloc which handles initializing the Bloc state based on the persisted state. This allows state to be persisted across hot restarts as well as complete app restarts.
Abstract cipher can be implemented to customize encryption.
Specialized Cubit which handles initializing the Cubit state based on the persisted state. This allows state to be persisted across application restarts.
Implementation of Storage which uses package:hive to persist and retrieve state changes from the local device.
A Streamable that provides synchronous access to the current state.
A StateStreamable that must be closed when no longer in use.
Interface which is used to persist and retrieve state changes.
Streamable<State extends Object?>
An object that provides access to a stream of states over time.
Transition<Event, State>
A Transition is the change from one state to another. Consists of the currentState, an event, and the nextState.


A mixin which enables automatic state persistence for Bloc and Cubit classes.


EventHandler<Event, State> = FutureOr<void> Function(Event event, Emitter<State> emit)
An event handler is responsible for reacting to an incoming Event and can emit zero or more states via the Emitter.
EventMapper<Event> = Stream<Event> Function(Event event)
Signature for a function which converts an incoming event into an outbound stream of events. Used when defining custom EventTransformers.
EventTransformer<Event> = Stream<Event> Function(Stream<Event> events, EventMapper<Event> mapper)
Used to change how events are processed. By default events are processed concurrently.

Exceptions / Errors

Reports that an object could not be serialized due to cyclic references. When the cycle is detected, a HydratedCyclicError is thrown.
Reports that an object could not be serialized. The unsupportedObject field holds object that failed to be serialized.
Exception thrown if there was no HydratedStorage specified. This is most likely due to forgetting to setup the HydratedStorage: