feat: stabilize hydrate side effect with nullable parameter (#66)

packages/rearch/lib/experimental.dart

@@ -30,47 +30,4 @@ extension ExperimentalSideEffects on SideEffectRegistrar {
       return (() => state, (T newState) => state = newState);
     });
   }
-
-  /// A mechanism to persist changes made to some provided state.
-  /// Unlike [persist], [hydrate] allows you to pass in the state to persist,
-  /// if there is one, to enable easier composition with other side effects.
-  ///
-  /// Defines a way to interact with a storage provider of your choice
-  /// through the [read] and [write] parameters.
-  /// - If [newData] is [Some], then [newData] will be persisted and
-  /// overwrite any existing persisted data.
-  /// - If [newData] is [None], then no changes will be made to the currently
-  /// persisted value (for when you don't have state to persist yet).
-  ///
-  /// [read] is only called once; it is assumed that if [write] is successful,
-  /// then calling [read] again would reflect the new state that we already
-  /// have access to. Thus, calling [read] again is skipped as an optimization.
-  // NOTE: experimental because I am not sold on the Option<T> parameter.
-  AsyncValue<T> hydrate<T>(
-    Option<T> newData, {
-    required Future<T> Function() read,
-    required Future<void> Function(T) write,
-  }) {
-    final readFuture = use.callonce(read);
-    final readState = use.future(readFuture);
-    final (getPrevData, setPrevData) =
-        use.rawValueWrapper<Option<T>>(None<T>.new);
-    final (getWriteFuture, setWriteFuture) =
-        use.rawValueWrapper<Future<T>?>(() => null);
-
-    if (newData case Some(value: final data)) {
-      final dataChanged =
-          getPrevData().map((prevData) => data != prevData).unwrapOr(true);
-      if (dataChanged) {
-        setPrevData(Some(data));
-        setWriteFuture(() async {
-          await write(data);
-          return data;
-        }());
-      }
-    }
-
-    final writeState = use.nullableFuture(getWriteFuture());
-    return (writeState ?? readState).fillInPreviousData(readState.data);
-  }
 }

packages/rearch/lib/src/side_effects.dart

@@ -323,6 +323,43 @@ extension BuiltinSideEffects on SideEffectRegistrar {
     return (state, persist);
   }
 
+  /// A mechanism to persist changes made to some provided state.
+  /// Unlike [persist], [hydrate] allows you to pass in the state to persist,
+  /// if there is one, to enable easier composition with other side effects.
+  ///
+  /// Defines a way to interact with a storage provider of your choice
+  /// through the [read] and [write] parameters.
+  /// - If [newData] is [Some], then [newData] will be persisted and
+  /// overwrite any existing persisted data.
+  /// - If [newData] is [None], then no changes will be made to the currently
+  /// persisted value (for when you don't have state to persist yet).
+  ///
+  /// [read] is only called once; it is assumed that if [write] is successful,
+  /// then calling [read] again would reflect the new state that we already
+  /// have access to. Thus, calling [read] again is skipped as an optimization.
+  AsyncValue<T> hydrate<T>(
+    T? newData, {
+    required Future<T> Function() read,
+    required Future<void> Function(T) write,
+  }) {
+    final readFuture = use.callonce(read);
+    final readState = use.future(readFuture);
+    final (getPrevData, setPrevData) = use.rawValueWrapper<T?>(() => null);
+    final (getWriteFuture, setWriteFuture) =
+        use.rawValueWrapper<Future<T>?>(() => null);
+
+    if (newData != null && newData != getPrevData()) {
+      setPrevData(newData);
+      setWriteFuture(() async {
+        await write(newData);
+        return newData;
+      }());
+    }
+
+    final writeState = use.nullableFuture(getWriteFuture());
+    return (writeState ?? readState).fillInPreviousData(readState.data);
+  }
+
   /// Allows you to trigger and watch [Future]s
   /// (called mutations, since they often mutate some state)
   /// from within the build function.

packages/rearch/test/side_effects_test.dart

@@ -1,4 +1,3 @@
-import 'package:rearch/experimental.dart';
 import 'package:rearch/rearch.dart';
 import 'package:test/test.dart';
 
@@ -61,11 +60,7 @@ void main() {
       CapsuleHandle use,
     ) {
       final (state, setState) = use.state<int?>(null);
-      final hydrateState = use.hydrate(
-        state != null ? Some(state) : const None<int>(),
-        read: read,
-        write: write,
-      );
+      final hydrateState = use.hydrate(state, read: read, write: write);
       return (hydrateState, setState);
     }