fix: assorted changes to alerter widget

Author: mattrltrent

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.0.4
+
+- Updates the `Alerter` widget to include an `Option` type for the previous alert state in its `listenAlertsIf` function, as it may be absent when there is no default alert, unlike the default state which is always present.
+
 ## 0.0.3
 
 - README updates.

README.md

@@ -150,10 +150,9 @@ class AuthTrent extends Trent<AuthTypes> {
         ..as<C>((_) {
           // Called if `C` is alerted
         }),
-
         // Only trigger listens if...
-        listenAlertsIf: (oldAlert, newAlert) => true,
-        listenStatesIf: (oldState, newState) => true,
+        listenAlertsIf: (oldAlert, newAlert) => true, // oldAlert is wrapped in an Option type because it may not exist
+        listenStatesIf: (oldState, newState) => true, // Both of these are pure types since there will always be an old and new state
       child: Container(),
   );
   ```
@@ -376,7 +375,6 @@ class AuthTrent extends Trent<AuthTypes> {
 - `watchMap<T, S>()`: Map state to specific UI widgets dynamically and reactively.
 
   ```dart
-  Copy code
   watchMap<WeatherTrent, WeatherTypes>(context, (mapper) {
     mapper
       ..as<Sunny>((state) => Text("Sunny: ${state.temperature}°C"))
@@ -512,7 +510,7 @@ class MyApp extends StatelessWidget {
 
 ### 5. Call Business Logic Functions From UI
 
-To call business logic functions from the UI, use the `get<T>()` utility to retrieve your Trent instance. This allows you to trigger state changes or logic directly from the UI layer.
+To call business logic functions from the UI, use the `get<T>()` utility to retrieve your Trent instance. This allows you to trigger state changes or logic directly from the UI layer. This, of course, is assuming you have a `Trent` instance registered in the `TrentManager`.
 
 #### Example
 
@@ -576,7 +574,7 @@ class WeatherScreen extends StatelessWidget {
 
 1. Retrieve the Trent instance: Use `get<T>()` to fetch the Trent instance. We use `get` instead of `watch` because `get` retrieves the Trent instance directly, while `watch` is used for reactive UI updates.
 2. Call methods: Trigger the desired business logic function, such as `updateToSunny`, `updateToRainy`, or `resetState`.
-3. UI updates: The UI automatically reacts to the state changes if `Digester`, `watch`, `watchMap`, or `Alerter` is used in the same widget tree.
+3. UI updates: The UI automatically reacts to the state changes if `Digester`, `watch`, `watchMap`, or `Alerter` are used in the widget tree below where the Trent was registered.
 
 ### 6. Use `Alerter`, `Digester`, `watch`, and `watchMap` in Your UI
 
@@ -597,6 +595,13 @@ class WeatherScreen extends StatelessWidget {
             );
           });
       },
+      listenAlertsIf: (oldState, newState) => true,
+      listenStates: (mapper) {
+        mapper
+          ..as<Sunny>((state) => print(state))
+          ..as<Rainy>((state) => print(state))
+          ..orElse((_) => const Text("No Data"));
+      },
       child: Digester<WeatherTrent, WeatherTypes>(
         child: (mapper) {
           mapper
@@ -648,7 +653,7 @@ class WeatherScreen extends StatelessWidget {
 
 ### 7. Testing Your Trent
 
-Add tests to ensure your Trent works as expected.
+Add tests to ensure your Trent works as expected. Existing tests can be found [here](https://github.com/mattrltrent/trent/tree/main/test).
 
 ```dart
 void main() {

example/lib/main.dart

@@ -79,7 +79,6 @@ class _HomeScreenState extends State<HomeScreen> {
               _latitudeController.clear();
               _longitudeController.clear();
             }),
-
           child: Padding(
             padding: const EdgeInsets.all(16.0),
             child: Column(
@@ -106,7 +105,8 @@ class _HomeScreenState extends State<HomeScreen> {
                 TextButton(
                   onPressed: () {
                     final latitude = double.tryParse(_latitudeController.text);
-                    final longitude = double.tryParse(_longitudeController.text);
+                    final longitude =
+                        double.tryParse(_longitudeController.text);
 
                     if (latitude != null && longitude != null) {
                       weatherTrent.fetchWeather(latitude, longitude);
@@ -122,8 +122,10 @@ class _HomeScreenState extends State<HomeScreen> {
                   child: Digester<WeatherTrent, WeatherTypes>(
                     child: (mapper) {
                       mapper
-                        ..as<NoData>((state) => const Text("Please enter location to fetch weather."))
-                        ..as<Loading>((state) => const CupertinoActivityIndicator())
+                        ..as<NoData>((state) => const Text(
+                            "Please enter location to fetch weather."))
+                        ..as<Loading>(
+                            (state) => const CupertinoActivityIndicator())
                         ..as<Data>((state) => Text(
                               "${state.location} has temperature ${state.temperature}°C",
                               style: const TextStyle(fontSize: 18),
@@ -192,7 +194,9 @@ class WeatherTrent extends Trent<WeatherTypes> {
     emit(Loading());
     Future.delayed(const Duration(milliseconds: 500), () {
       final mockData = {
-        "temperature": double.parse((15 + (latitude % 10) + Random().nextDouble() * 5).toStringAsFixed(1)),
+        "temperature": double.parse(
+            (15 + (latitude % 10) + Random().nextDouble() * 5)
+                .toStringAsFixed(1)),
         "location": "$latitude, $longitude",
       };
 

lib/src/logic/trent.dart

@@ -96,15 +96,18 @@ abstract class Trents<Base> extends ChangeNotifier {
   /// to return to D(value: 10) instead of D(value: some_value_you_must_define).
   Option<T> getExStateAs<T extends Base>() {
     return _lastStates[T] != null
-        ? _lastStates[T]!.match(some: (v) => Option.some(v as T), none: () => Option<T>.none())
+        ? _lastStates[T]!.match(
+            some: (v) => Option.some(v as T), none: () => Option<T>.none())
         : Option<T>.none();
   }
 
   /// Retrieve the current state as a specific type.
   ///
   /// Will return None if the current state is not of the specified type.
   Option<T> getCurrStateAs<T extends Base>() {
-    return _state.runtimeType == T ? Option.some(_state as T) : Option<T>.none();
+    return _state.runtimeType == T
+        ? Option.some(_state as T)
+        : Option<T>.none();
   }
 
   /// Dispose of the Trent.
@@ -129,6 +132,7 @@ abstract class Copyable<T> {
 }
 
 /// A generic Trent that manages state transitions.
-abstract class Trent<Base extends EquatableCopyable<Base>> extends Trents<Base> {
+abstract class Trent<Base extends EquatableCopyable<Base>>
+    extends Trents<Base> {
   Trent(super.state);
 }

lib/src/widgets/alerter.dart

@@ -9,7 +9,8 @@ class Alerter<TrentType extends Trents<StateType>, StateType>
   final void Function(LogicSubTypeMapper<StateType> mapper)? listenAlerts;
 
   /// Determines whether `listenAlerts` should trigger for a given alert.
-  final bool Function(StateType oldAlert, StateType newAlert)? listenAlertsIf;
+  final bool Function(Option<StateType> oldAlert, StateType newAlert)?
+      listenAlertsIf;
 
   /// Called when the normal state changes, using a mapper.
   final void Function(LogicSubTypeMapper<StateType> mapper)? listenStates;
@@ -36,15 +37,15 @@ class Alerter<TrentType extends Trents<StateType>, StateType>
 class AlerterState<TrentType extends Trents<StateType>, StateType>
     extends State<Alerter<TrentType, StateType>> {
   late final TrentType sm = get<TrentType>(context);
-  late StateType _previousAlert; // Tracks the previous alert state
+  Option<StateType> _previousAlert =
+      Option.none(); // Tracks the previous alert state
   late StateType _previousState; // Tracks the previous normal state
   bool _hasInitialStateTriggered =
       false; // Tracks if the initial state has been emitted
 
   @override
   void initState() {
     super.initState();
-    _previousAlert = sm.state;
     _previousState = sm.state;
 
     // Listen to the alert stream
@@ -57,7 +58,7 @@ class AlerterState<TrentType extends Trents<StateType>, StateType>
           widget.listenAlerts!(mapper);
         }
       }
-      _previousAlert = alert;
+      _previousAlert = Option.some(alert);
     });
 
     // Listen to the state stream

pubspec.yaml

@@ -1,6 +1,6 @@
 name: trent
 description: A Flutter package for simple, scalable, and reactive state management with built-in dependency injection and efficient stream-based state handling.
-version: 0.0.3
+version: 0.0.4
 
 homepage: https://matthewtrent.me
 repository: https://github.com/mattrltrent/trent