feat: #3555

packages/bloc/lib/src/bloc.dart

@@ -148,7 +148,7 @@ abstract class Bloc<Event, State> extends BlocBase<State>
   /// {@endtemplate}
   @visibleForTesting
   @override
-  void emit(State state) => super.emit(state);
+  Emitter<State> get emit => super.emit;
 
   /// Register event handler for an event of type `E`.
   /// There should only ever be one event handler per event type `E`.

packages/bloc/lib/src/bloc_base.dart

@@ -28,11 +28,11 @@ abstract class Closable {
   bool get isClosed;
 }
 
-/// An object that can emit new states.
+/// An object that can emit new states via the [Emitter].
 // ignore: one_member_abstracts
 abstract class Emittable<State extends Object?> {
-  /// Emits a new [state].
-  void emit(State state);
+  /// The emitter.
+  Emitter<State> get emit;
 }
 
 /// A generic destination for errors.
@@ -90,21 +90,21 @@ abstract class BlocBase<State>
   @protected
   @visibleForTesting
   @override
-  void emit(State state) {
-    try {
-      if (isClosed) {
-        throw StateError('Cannot emit new states after calling close');
-      }
-      if (state == _state && _emitted) return;
-      onChange(Change<State>(currentState: this.state, nextState: state));
-      _state = state;
-      _stateController.add(_state);
-      _emitted = true;
-    } catch (error, stackTrace) {
-      onError(error, stackTrace);
-      rethrow;
-    }
-  }
+  Emitter<State> get emit => _Emitter((state) {
+        try {
+          if (isClosed) {
+            throw StateError('Cannot emit new states after calling close');
+          }
+          if (state == _state && _emitted) return;
+          onChange(Change<State>(currentState: this.state, nextState: state));
+          _state = state;
+          _stateController.add(_state);
+          _emitted = true;
+        } catch (error, stackTrace) {
+          onError(error, stackTrace);
+          rethrow;
+        }
+      });
 
   /// Called whenever a [change] occurs with the given [change].
   /// A [change] occurs when a new `state` is emitted.

packages/bloc/lib/src/emitter.dart

@@ -9,6 +9,9 @@
 ///
 /// {@endtemplate}
 abstract class Emitter<State> {
+  /// {@macro emitter}
+  factory Emitter(void Function(State state) emit) => _Emitter(emit);
+
   /// Subscribes to the provided [stream] and invokes the [onData] callback
   /// when the [stream] emits new data.
   ///

packages/replay_bloc/lib/src/replay_bloc.dart

@@ -94,42 +94,42 @@ mixin ReplayBlocMixin<Event extends ReplayEvent, State> on Bloc<Event, State> {
   }
 
   @override
-  void emit(State state) {
-    _changeStack.add(
-      _Change<State>(
-        this.state,
-        state,
-        () {
-          final event = _Redo();
-          onEvent(event);
-          onTransition(
-            Transition(
-              currentState: this.state,
-              event: event,
-              nextState: state,
-            ),
-          );
-          // ignore: invalid_use_of_visible_for_testing_member
-          super.emit(state);
-        },
-        (val) {
-          final event = _Undo();
-          onEvent(event);
-          onTransition(
-            Transition(
-              currentState: this.state,
-              event: event,
-              nextState: val,
-            ),
-          );
-          // ignore: invalid_use_of_visible_for_testing_member
-          super.emit(val);
-        },
-      ),
-    );
-    // ignore: invalid_use_of_visible_for_testing_member
-    super.emit(state);
-  }
+  Emitter<State> get emit => Emitter((state) {
+        _changeStack.add(
+          _Change<State>(
+            this.state,
+            state,
+            () {
+              final event = _Redo();
+              onEvent(event);
+              onTransition(
+                Transition(
+                  currentState: this.state,
+                  event: event,
+                  nextState: state,
+                ),
+              );
+              // ignore: invalid_use_of_visible_for_testing_member
+              super.emit(state);
+            },
+            (val) {
+              final event = _Undo();
+              onEvent(event);
+              onTransition(
+                Transition(
+                  currentState: this.state,
+                  event: event,
+                  nextState: val,
+                ),
+              );
+              // ignore: invalid_use_of_visible_for_testing_member
+              super.emit(val);
+            },
+          ),
+        );
+        // ignore: invalid_use_of_visible_for_testing_member
+        super.emit(state);
+      });
 
   /// Undo the last change.
   void undo() => _changeStack.undo();

packages/replay_bloc/lib/src/replay_cubit.dart

@@ -63,17 +63,17 @@ mixin ReplayCubitMixin<State> on Cubit<State> {
   set limit(int limit) => _changeStack.limit = limit;
 
   @override
-  void emit(State state) {
-    _changeStack.add(
-      _Change<State>(
-        this.state,
-        state,
-        () => super.emit(state),
-        (val) => super.emit(val),
-      ),
-    );
-    super.emit(state);
-  }
+  Emitter<State> get emit => Emitter((state) {
+        _changeStack.add(
+          _Change<State>(
+            this.state,
+            state,
+            () => super.emit(state),
+            (val) => super.emit(val),
+          ),
+        );
+        super.emit(state);
+      });
 
   /// Undo the last change.
   void undo() => _changeStack.undo();