update to rxdart 0.21.0

Author: cadooo

lib/hydrated.dart

@@ -118,6 +118,9 @@ class HydratedSubject<T> extends Subject<T> implements ValueObservable<T> {
   /// Set and emit the new value
   set value(T newValue) => add(newValue);
 
+  @override
+  bool get hasValue => _wrapper.latestValue != null;
+
   /// Hydrates the HydratedSubject with a value stored on the user's device.
   ///
   /// Must be called to retreive values stored on the device.

pubspec.yaml

@@ -11,7 +11,7 @@ dependencies:
   flutter:
     sdk: flutter
 
-  rxdart: ^0.20.0
+  rxdart: ^0.21.0
   shared_preferences: ^0.5.1
 
 dev_dependencies:

test/hydrated_test.dart

@@ -114,14 +114,17 @@ Future<void> testHydrated<T>(
 
   /// null before hydrate
   expect(subject.value, equals(null));
+  expect(subject.hasValue, equals(false));
 
   /// properly hydrates
   await completer.future;
   expect(subject.value, equals(first));
+  expect(subject.hasValue, equals(true));
 
   /// add values
   subject.add(second);
   expect(subject.value, equals(second));
+  expect(subject.hasValue, equals(true));
 
   /// check value in store
   final prefs = await SharedPreferences.getInstance();