update to 4.0

-## [4.0.0-nullsafety.2] 
+## [4.0.0] 
 - Added append function to StateMixin. Now is possible track loading, success and error handle of your application with ONE LINE OF CODE. Ex: append(()=> api.getUser);
 - Added append function to StateMixin. Now is possible track loading, success and error handle of your application with ONE LINE OF CODE. Ex: append(()=> api.getUser);
-
-## [4.0.0-nullsafety.0] 
 - Migrate to null-safety 
 - Migrate to null-safety 
 - Added ScrollMixin to controllers
 - Added ScrollMixin to controllers
 - Added loadingMore status to RxStatus
 - Added loadingMore status to RxStatus

@@ -28,7 +28,7 @@ dependencies:
   # Use with the CupertinoIcons class for iOS style icons.
   # Use with the CupertinoIcons class for iOS style icons.
   get:
   get:
     path: ../
     path: ../
-  get_test: ^3.13.3
+  #get_test: ^3.13.3
 
 
 dependency_overrides:
 dependency_overrides:
   get:
   get:

@@ -87,7 +87,7 @@ void main() {
   });
   });
 
 
   test('ever', () async {
   test('ever', () async {
-    RxString count = ''.obs;
+    final count = ''.obs;
     var result = '';
     var result = '';
     ever<String>(count, (value) {
     ever<String>(count, (value) {
       result = value;
       result = value;

@@ -1011,7 +1011,7 @@ you can only use widgets and widget functions here''';
     return key;
     return key;
   }
   }
 
 
-  GlobalKey<NavigatorState>? nestedKey(int key) {
+  GlobalKey<NavigatorState>? nestedKey(dynamic key) {
     keys.putIfAbsent(key, () => GlobalKey<NavigatorState>());
     keys.putIfAbsent(key, () => GlobalKey<NavigatorState>());
     return keys[key];
     return keys[key];
   }
   }
@@ -1158,7 +1158,7 @@ Since version 2.8 it is possible to access the properties
 
 
   GlobalKey<NavigatorState>? get key => getxController.key;
   GlobalKey<NavigatorState>? get key => getxController.key;
 
 
-  Map<int, GlobalKey<NavigatorState>> get keys => getxController.keys;
+  Map<dynamic, GlobalKey<NavigatorState>> get keys => getxController.keys;
 
 
   GetMaterialController get rootController => getxController;
   GetMaterialController get rootController => getxController;
 
 

@@ -310,3 +310,64 @@ class GetMaterialApp extends StatelessWidget {
               //   actions: actions,
               //   actions: actions,
             ));
             ));
 }
 }
+
+class GetNavigator extends StatelessWidget {
+  final List<GetPage> getPages;
+
+  const GetNavigator(
+      {Key? key,
+      required this.getPages,
+      this.pages = const <Page<dynamic>>[],
+      this.onPopPage,
+      this.initialRoute,
+      this.onGenerateInitialRoutes = Navigator.defaultGenerateInitialRoutes,
+      this.onGenerateRoute,
+      this.onUnknownRoute,
+      this.transitionDelegate = const DefaultTransitionDelegate<dynamic>(),
+      this.reportsRouteUpdateToEngine = false,
+      this.observers = const <NavigatorObserver>[],
+      this.restorationScopeId,
+      this.unKnownRoute})
+      : super(key: key);
+
+  final List<Page<dynamic>> pages;
+
+  final GetPage? unKnownRoute;
+
+  final PopPageCallback? onPopPage;
+
+  final TransitionDelegate<dynamic> transitionDelegate;
+
+  final String? initialRoute;
+
+  final RouteFactory? onGenerateRoute;
+
+  final RouteFactory? onUnknownRoute;
+
+  final List<NavigatorObserver> observers;
+
+  final String? restorationScopeId;
+
+  static const String defaultRouteName = '/';
+
+  final RouteListFactory onGenerateInitialRoutes;
+
+  final bool reportsRouteUpdateToEngine;
+
+  @override
+  Widget build(Object context) {
+    return Navigator(
+      pages: getPages,
+      onPopPage: onPopPage,
+      initialRoute: initialRoute,
+      onGenerateInitialRoutes: onGenerateInitialRoutes,
+      onGenerateRoute: onGenerateRoute,
+      onUnknownRoute: onUnknownRoute,
+      transitionDelegate: transitionDelegate,
+      reportsRouteUpdateToEngine: reportsRouteUpdateToEngine,
+      observers: observers,
+      restorationScopeId: restorationScopeId,
+      key: Get.nestedKey(key),
+    );
+  }
+}

 import 'package:flutter/widgets.dart';
 import 'package:flutter/widgets.dart';
 
 
+import '../../../get_core/src/get_main.dart';
 import '../../../get_instance/get_instance.dart';
 import '../../../get_instance/get_instance.dart';
 import '../../get_navigation.dart';
 import '../../get_navigation.dart';
 import 'custom_transition.dart';
 import 'custom_transition.dart';
@@ -11,7 +12,8 @@ class PathDecoded {
   final List<String?> keys;
   final List<String?> keys;
 }
 }
 
 
-class GetPage {
+class GetPage<T> extends Page<T> {
+  @override
   final String name;
   final String name;
   final GetPageBuilder page;
   final GetPageBuilder page;
   final bool? popGesture;
   final bool? popGesture;
@@ -31,6 +33,7 @@ class GetPage {
   final List<GetPage>? children;
   final List<GetPage>? children;
   final List<GetMiddleware>? middlewares;
   final List<GetMiddleware>? middlewares;
   final PathDecoded path;
   final PathDecoded path;
+  final GetPage? unknownRoute;
 
 
   GetPage({
   GetPage({
     required this.name,
     required this.name,
@@ -51,6 +54,7 @@ class GetPage {
     this.fullscreenDialog = false,
     this.fullscreenDialog = false,
     this.children,
     this.children,
     this.middlewares,
     this.middlewares,
+    this.unknownRoute,
   }) : path = _nameToRegex(name);
   }) : path = _nameToRegex(name);
 
 
   static PathDecoded _nameToRegex(String path) {
   static PathDecoded _nameToRegex(String path) {
@@ -74,7 +78,7 @@ class GetPage {
     return PathDecoded(RegExp('^$stringPath\$'), keys);
     return PathDecoded(RegExp('^$stringPath\$'), keys);
   }
   }
 
 
-  GetPage copyWith({
+  GetPage copy({
     String? name,
     String? name,
     GetPageBuilder? page,
     GetPageBuilder? page,
     bool? popGesture,
     bool? popGesture,
@@ -115,4 +119,14 @@ class GetPage {
       middlewares: middlewares ?? this.middlewares,
       middlewares: middlewares ?? this.middlewares,
     );
     );
   }
   }
+
+  @override
+  Object? get arguments => Get.arguments;
+
+  @override
+  Route<T> createRoute(BuildContext context) {
+    return PageRedirect(
+            RouteSettings(name: name, arguments: Get.arguments), unknownRoute)
+        .page<T>();
+  }
 }
 }

@@ -165,10 +165,10 @@ class PageRedirect {
       {this.isUnknown = false, this.route});
       {this.isUnknown = false, this.route});
 
 
   // redirect all pages that needes redirecting
   // redirect all pages that needes redirecting
-  GetPageRoute page() {
+  GetPageRoute<T> page<T>() {
     while (needRecheck()) {}
     while (needRecheck()) {}
     return isUnknown
     return isUnknown
-        ? GetPageRoute(
+        ? GetPageRoute<T>(
             page: unknownRoute!.page,
             page: unknownRoute!.page,
             parameter: unknownRoute!.parameter,
             parameter: unknownRoute!.parameter,
             settings: RouteSettings(
             settings: RouteSettings(
@@ -185,7 +185,7 @@ class PageRedirect {
             fullscreenDialog: unknownRoute!.fullscreenDialog,
             fullscreenDialog: unknownRoute!.fullscreenDialog,
             middlewares: unknownRoute!.middlewares,
             middlewares: unknownRoute!.middlewares,
           )
           )
-        : GetPageRoute(
+        : GetPageRoute<T>(
             page: route!.page,
             page: route!.page,
             parameter: route!.parameter,
             parameter: route!.parameter,
             settings: RouteSettings(
             settings: RouteSettings(

@@ -236,6 +236,8 @@ abstract class _RxImpl<T> extends RxNotifier<T> with RxObjectMixin<T> {
   }
   }
 }
 }
 
 
+extension RxBoolExt on Rx<bool> {}
+
 /// Rx class for `bool` Type.
 /// Rx class for `bool` Type.
 class RxBool extends _RxImpl<bool> {
 class RxBool extends _RxImpl<bool> {
   RxBool(bool initial) : super(initial);
   RxBool(bool initial) : super(initial);
@@ -266,143 +268,12 @@ class RxBool extends _RxImpl<bool> {
   }
   }
 }
 }
 
 
-/// Rx class for `String` Type.
-class RxString extends _RxImpl<String> implements Comparable<String>, Pattern {
-  RxString(String initial) : super(initial);
-
-  String operator +(String val) => _value + val;
-
-  /// Compares this string to [other].
-  @override
-  int compareTo(String other) {
-    return value.compareTo(other);
-  }
-
-  /// Returns true if this string ends with [other]. For example:
-  ///
-  ///     'Dart'.endsWith('t'); // true
-  bool endsWith(String other) {
-    return value.endsWith(other);
-  }
-
-  /// Returns true if this string starts with a match of [pattern].
-  bool startsWith(Pattern pattern, [int index = 0]) {
-    return value.startsWith(pattern, index);
-  }
-
-  /// Returns the position of the first match of [pattern] in this string
-  int indexOf(Pattern pattern, [int start = 0]) {
-    return value.indexOf(pattern, start);
-  }
-
-  /// Returns the starting position of the last match [pattern] in this string,
-  /// searching backward starting at [start], inclusive:
-  int lastIndexOf(Pattern pattern, [int? start]) {
-    return value.lastIndexOf(pattern, start);
-  }
-
-  /// Returns true if this string is empty.
-  bool get isEmpty => value.isEmpty;
-
-  /// Returns true if this string is not empty.
-  bool get isNotEmpty => !isEmpty;
-
-  /// Returns the substring of this string that extends from [startIndex],
-  /// inclusive, to [endIndex], exclusive
-  String substring(int startIndex, [int? endIndex]) {
-    return value.substring(startIndex, endIndex);
-  }
-
-  /// Returns the string without any leading and trailing whitespace.
-  String trim() {
-    return value.trim();
-  }
-
-  /// Returns the string without any leading whitespace.
-  ///
-  /// As [trim], but only removes leading whitespace.
-  String trimLeft() {
-    return value.trimLeft();
-  }
-
-  /// Returns the string without any trailing whitespace.
-  ///
-  /// As [trim], but only removes trailing whitespace.
-  String trimRight() {
-    return value.trimRight();
-  }
-
-  /// Pads this string on the left if it is shorter than [width].
-  ///
-  /// Return a new string that prepends [padding] onto this string
-  /// one time for each position the length is less than [width].
-  String padLeft(int width, [String padding = ' ']) {
-    return value.padLeft(width, padding);
-  }
-
-  /// Pads this string on the right if it is shorter than [width].
-
-  /// Return a new string that appends [padding] after this string
-  /// one time for each position the length is less than [width].
-  String padRight(int width, [String padding = ' ']) {
-    return value.padRight(width, padding);
-  }
-
-  /// Returns true if this string contains a match of [other]:
-  bool contains(Pattern other, [int startIndex = 0]) {
-    return value.contains(other, startIndex);
-  }
-
-  /// Replaces all substrings that match [from] with [replace].
-  String replaceAll(Pattern from, String replace) {
-    return value.replaceAll(from, replace);
-  }
-
-  /// Splits the string at matches of [pattern] and returns a list
-  /// of substrings.
-  List<String> split(Pattern pattern) {
-    return value.split(pattern);
-  }
-
-  /// Returns an unmodifiable list of the UTF-16 code units of this string.
-  List<int> get codeUnits => value.codeUnits;
-
-  /// Returns an [Iterable] of Unicode code-points of this string.
-  ///
-  /// If the string contains surrogate pairs, they are combined and returned
-  /// as one integer by this iterator. Unmatched surrogate halves are treated
-  /// like valid 16-bit code-units.
-  Runes get runes => value.runes;
-
-  /// Converts all characters in this string to lower case.
-  /// If the string is already in all lower case, this method returns `this`.
-  String toLowerCase() {
-    return value.toLowerCase();
-  }
-
-  /// Converts all characters in this string to upper case.
-  /// If the string is already in all upper case, this method returns `this`.
-  String toUpperCase() {
-    return value.toUpperCase();
-  }
-
-  @override
-  Iterable<Match> allMatches(String string, [int start = 0]) {
-    return value.allMatches(string, start);
-  }
-
-  @override
-  Match? matchAsPrefix(String string, [int start = 0]) {
-    return value.matchAsPrefix(string, start);
-  }
-}
-
 /// Foundation class used for custom `Types` outside the common native Dart
 /// Foundation class used for custom `Types` outside the common native Dart
 /// types.
 /// types.
 /// For example, any custom "Model" class, like User().obs will use `Rx` as
 /// For example, any custom "Model" class, like User().obs will use `Rx` as
 /// wrapper.
 /// wrapper.
-class Rx<T> extends _RxImpl<T?> {
-  Rx([T? initial]) : super(initial);
+class Rx<T> extends _RxImpl<T> {
+  Rx(T initial) : super(initial);
 
 
   @override
   @override
   dynamic toJson() {
   dynamic toJson() {

 part of rx_types;
 part of rx_types;
 
 
-/// Base Rx class for all num Rx's.
-abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
-  _BaseRxNum(T initial) : super(initial);
-
-  /// Addition operator. */
-
+extension RxNumExt<T extends num> on Rx<T> {
   /// Multiplication operator.
   /// Multiplication operator.
-  num operator *(num other) => value! * other;
+  num operator *(num other) => value * other;
 
 
   /// Euclidean modulo operator.
   /// Euclidean modulo operator.
   ///
   ///
@@ -22,10 +17,10 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// The sign of the returned value `r` is always positive.
   /// The sign of the returned value `r` is always positive.
   ///
   ///
   /// See [remainder] for the remainder of the truncating division.
   /// See [remainder] for the remainder of the truncating division.
-  num operator %(num other) => value! % other;
+  num operator %(num other) => value % other;
 
 
   /// Division operator.
   /// Division operator.
-  double operator /(num other) => value! / other;
+  double operator /(num other) => value / other;
 
 
   /// Truncating division operator.
   /// Truncating division operator.
   ///
   ///
@@ -34,10 +29,10 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   ///
   ///
   /// If both operands are [int]s then `a ~/ b` performs the truncating
   /// If both operands are [int]s then `a ~/ b` performs the truncating
   /// integer division.
   /// integer division.
-  int operator ~/(num other) => value! ~/ other;
+  int operator ~/(num other) => value ~/ other;
 
 
   /// Negate operator.
   /// Negate operator.
-  num operator -() => -value!;
+  num operator -() => -value;
 
 
   /// Returns the remainder of the truncating division of `this` by [other].
   /// Returns the remainder of the truncating division of `this` by [other].
   ///
   ///
@@ -45,40 +40,40 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// `this == (this ~/ other) * other + r`.
   /// `this == (this ~/ other) * other + r`.
   /// As a consequence the remainder `r` has the same sign as the divider
   /// As a consequence the remainder `r` has the same sign as the divider
   /// `this`.
   /// `this`.
-  num remainder(num other) => value!.remainder(other);
+  num remainder(num other) => value.remainder(other);
 
 
   /// Relational less than operator.
   /// Relational less than operator.
-  bool operator <(num other) => value! < other;
+  bool operator <(num other) => value < other;
 
 
   /// Relational less than or equal operator.
   /// Relational less than or equal operator.
-  bool operator <=(num other) => value! <= other;
+  bool operator <=(num other) => value <= other;
 
 
   /// Relational greater than operator.
   /// Relational greater than operator.
-  bool operator >(num other) => value! > other;
+  bool operator >(num other) => value > other;
 
 
   /// Relational greater than or equal operator.
   /// Relational greater than or equal operator.
-  bool operator >=(num other) => value! >= other;
+  bool operator >=(num other) => value >= other;
 
 
   /// True if the number is the double Not-a-Number value; otherwise, false.
   /// True if the number is the double Not-a-Number value; otherwise, false.
-  bool get isNaN => value!.isNaN;
+  bool get isNaN => value.isNaN;
 
 
   /// True if the number is negative; otherwise, false.
   /// True if the number is negative; otherwise, false.
   ///
   ///
   /// Negative numbers are those less than zero, and the double `-0.0`.
   /// Negative numbers are those less than zero, and the double `-0.0`.
-  bool get isNegative => value!.isNegative;
+  bool get isNegative => value.isNegative;
 
 
   /// True if the number is positive infinity or negative infinity; otherwise,
   /// True if the number is positive infinity or negative infinity; otherwise,
   /// false.
   /// false.
-  bool get isInfinite => value!.isInfinite;
+  bool get isInfinite => value.isInfinite;
 
 
   /// True if the number is finite; otherwise, false.
   /// True if the number is finite; otherwise, false.
   ///
   ///
   /// The only non-finite numbers are NaN, positive infinity, and
   /// The only non-finite numbers are NaN, positive infinity, and
   /// negative infinity.
   /// negative infinity.
-  bool get isFinite => value!.isFinite;
+  bool get isFinite => value.isFinite;
 
 
   /// Returns the absolute value of this [num].
   /// Returns the absolute value of this [num].
-  num abs() => value!.abs();
+  num abs() => value.abs();
 
 
   /// Returns minus one, zero or plus one depending on the sign and
   /// Returns minus one, zero or plus one depending on the sign and
   /// numerical value of the number.
   /// numerical value of the number.
@@ -96,7 +91,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   ///     n == n.sign * n.abs()
   ///     n == n.sign * n.abs()
   ///
   ///
   /// for all numbers `n` (except NaN, because NaN isn't `==` to itself).
   /// for all numbers `n` (except NaN, because NaN isn't `==` to itself).
-  num get sign => value!.sign;
+  num get sign => value.sign;
 
 
   /// Returns the integer closest to `this`.
   /// Returns the integer closest to `this`.
   ///
   ///
@@ -104,23 +99,23 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   ///  `(3.5).round() == 4` and `(-3.5).round() == -4`.
   ///  `(3.5).round() == 4` and `(-3.5).round() == -4`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  int round() => value!.round();
+  int round() => value.round();
 
 
   /// Returns the greatest integer no greater than `this`.
   /// Returns the greatest integer no greater than `this`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  int floor() => value!.floor();
+  int floor() => value.floor();
 
 
   /// Returns the least integer no smaller than `this`.
   /// Returns the least integer no smaller than `this`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  int ceil() => value!.ceil();
+  int ceil() => value.ceil();
 
 
   /// Returns the integer obtained by discarding any fractional
   /// Returns the integer obtained by discarding any fractional
   /// digits from `this`.
   /// digits from `this`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  int truncate() => value!.truncate();
+  int truncate() => value.truncate();
 
 
   /// Returns the double integer value closest to `this`.
   /// Returns the double integer value closest to `this`.
   ///
   ///
@@ -138,7 +133,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// The result is always a double.
   /// The result is always a double.
   /// If this is a numerically large integer, the result may be an infinite
   /// If this is a numerically large integer, the result may be an infinite
   /// double.
   /// double.
-  double roundToDouble() => value!.roundToDouble();
+  double roundToDouble() => value.roundToDouble();
 
 
   /// Returns the greatest double integer value no greater than `this`.
   /// Returns the greatest double integer value no greater than `this`.
   ///
   ///
@@ -151,7 +146,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// The result is always a double.
   /// The result is always a double.
   /// If this is a numerically large integer, the result may be an infinite
   /// If this is a numerically large integer, the result may be an infinite
   /// double.
   /// double.
-  double floorToDouble() => value!.floorToDouble();
+  double floorToDouble() => value.floorToDouble();
 
 
   /// Returns the least double integer value no smaller than `this`.
   /// Returns the least double integer value no smaller than `this`.
   ///
   ///
@@ -164,7 +159,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// The result is always a double.
   /// The result is always a double.
   /// If this is a numerically large integer, the result may be an infinite
   /// If this is a numerically large integer, the result may be an infinite
   /// double.
   /// double.
-  double ceilToDouble() => value!.ceilToDouble();
+  double ceilToDouble() => value.ceilToDouble();
 
 
   /// Returns the double integer value obtained by discarding any fractional
   /// Returns the double integer value obtained by discarding any fractional
   /// digits from the double value of `this`.
   /// digits from the double value of `this`.
@@ -179,7 +174,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// The result is always a double.
   /// The result is always a double.
   /// If this is a numerically large integer, the result may be an infinite
   /// If this is a numerically large integer, the result may be an infinite
   /// double.
   /// double.
-  double truncateToDouble() => value!.truncateToDouble();
+  double truncateToDouble() => value.truncateToDouble();
 
 
   /// Returns this [num] clamped to be in the range [lowerLimit]-[upperLimit].
   /// Returns this [num] clamped to be in the range [lowerLimit]-[upperLimit].
   ///
   ///
@@ -190,17 +185,17 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   /// The arguments [lowerLimit] and [upperLimit] must form a valid range where
   /// The arguments [lowerLimit] and [upperLimit] must form a valid range where
   /// `lowerLimit.compareTo(upperLimit) <= 0`.
   /// `lowerLimit.compareTo(upperLimit) <= 0`.
   num clamp(num lowerLimit, num upperLimit) =>
   num clamp(num lowerLimit, num upperLimit) =>
-      value!.clamp(lowerLimit, upperLimit);
+      value.clamp(lowerLimit, upperLimit);
 
 
   /// Truncates this [num] to an integer and returns the result as an [int]. */
   /// Truncates this [num] to an integer and returns the result as an [int]. */
-  int toInt() => value!.toInt();
+  int toInt() => value.toInt();
 
 
   /// Return this [num] as a [double].
   /// Return this [num] as a [double].
   ///
   ///
   /// If the number is not representable as a [double], an
   /// If the number is not representable as a [double], an
   /// approximation is returned. For numerically large integers, the
   /// approximation is returned. For numerically large integers, the
   /// approximation may be infinite.
   /// approximation may be infinite.
-  double toDouble() => value!.toDouble();
+  double toDouble() => value.toDouble();
 
 
   /// Returns a decimal-point string-representation of `this`.
   /// Returns a decimal-point string-representation of `this`.
   ///
   ///
@@ -225,7 +220,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   ///     10000000000000000.toStringAsFixed(4); // 10000000000000000.0000
   ///     10000000000000000.toStringAsFixed(4); // 10000000000000000.0000
   ///     5.25.toStringAsFixed(0); // 5
   ///     5.25.toStringAsFixed(0); // 5
   String toStringAsFixed(int fractionDigits) =>
   String toStringAsFixed(int fractionDigits) =>
-      value!.toStringAsFixed(fractionDigits);
+      value.toStringAsFixed(fractionDigits);
 
 
   /// Returns an exponential string-representation of `this`.
   /// Returns an exponential string-representation of `this`.
   ///
   ///
@@ -246,7 +241,7 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   ///     123456.toStringAsExponential(3); // 1.235e+5
   ///     123456.toStringAsExponential(3); // 1.235e+5
   ///     123.toStringAsExponential(0);    // 1e+2
   ///     123.toStringAsExponential(0);    // 1e+2
   String toStringAsExponential([int? fractionDigits]) =>
   String toStringAsExponential([int? fractionDigits]) =>
-      value!.toStringAsExponential(fractionDigits);
+      value.toStringAsExponential(fractionDigits);
 
 
   /// Converts `this` to a double and returns a string representation with
   /// Converts `this` to a double and returns a string representation with
   /// exactly [precision] significant digits.
   /// exactly [precision] significant digits.
@@ -265,72 +260,137 @@ abstract class _BaseRxNum<T extends num?> extends _RxImpl<T> {
   ///     0.00000012345.toStringAsPrecision(15); // 1.23450000000000e-7
   ///     0.00000012345.toStringAsPrecision(15); // 1.23450000000000e-7
   ///     0.0000012345.toStringAsPrecision(15);  // 0.00000123450000000000
   ///     0.0000012345.toStringAsPrecision(15);  // 0.00000123450000000000
   String toStringAsPrecision(int precision) =>
   String toStringAsPrecision(int precision) =>
-      value!.toStringAsPrecision(precision);
+      value.toStringAsPrecision(precision);
 }
 }
 
 
-class RxNum extends _BaseRxNum<num> {
-  RxNum(num initial) : super(initial);
+extension RxnNumExt<T extends num> on Rx<T?> {
+  /// Multiplication operator.
+  num? operator *(num other) {
+    if (value != null) {
+      return value! * other;
+    }
+  }
 
 
-  num? operator +(num other) {
-    value += other;
-    return value;
+  /// Euclidean modulo operator.
+  ///
+  /// Returns the remainder of the Euclidean division. The Euclidean division of
+  /// two integers `a` and `b` yields two integers `q` and `r` such that
+  /// `a == b * q + r` and `0 <= r < b.abs()`.
+  ///
+  /// The Euclidean division is only defined for integers, but can be easily
+  /// extended to work with doubles. In that case `r` may have a non-integer
+  /// value, but it still verifies `0 <= r < |b|`.
+  ///
+  /// The sign of the returned value `r` is always positive.
+  ///
+  /// See [remainder] for the remainder of the truncating division.
+  num? operator %(num other) {
+    if (value != null) {
+      return value! % other;
+    }
   }
   }
 
 
-  /// Subtraction operator.
-  num? operator -(num other) {
-    value -= other;
-    return value;
+  /// Division operator.
+  double? operator /(num other) {
+    if (value != null) {
+      return value! / other;
+    }
   }
   }
-}
 
 
-class RxDouble extends _BaseRxNum<double?> {
-  RxDouble([double? initial]) : super(initial);
+  /// Truncating division operator.
+  ///
+  /// If either operand is a [double] then the result of the truncating division
+  /// `a ~/ b` is equivalent to `(a / b).truncate().toInt()`.
+  ///
+  /// If both operands are [int]s then `a ~/ b` performs the truncating
+  /// integer division.
+  int? operator ~/(num other) {
+    if (value != null) {
+      return value! ~/ other;
+    }
+  }
 
 
-  /// Addition operator.
-  RxDouble operator +(num other) {
-    value = value! + other;
-    return this;
+  /// Negate operator.
+  num? operator -() {
+    if (value != null) {
+      return -value!;
+    }
   }
   }
 
 
-  /// Subtraction operator.
-  RxDouble operator -(num other) {
-    value = value! - other;
-    return this;
+  /// Returns the remainder of the truncating division of `this` by [other].
+  ///
+  /// The result `r` of this operation satisfies:
+  /// `this == (this ~/ other) * other + r`.
+  /// As a consequence the remainder `r` has the same sign as the divider
+  /// `this`.
+  num? remainder(num other) => value?.remainder(other);
+
+  /// Relational less than operator.
+  bool? operator <(num other) {
+    if (value != null) {
+      return value! < other;
+    }
   }
   }
 
 
-  /// Multiplication operator.
-  @override
-  double operator *(num other) => value! * other;
+  /// Relational less than or equal operator.
+  bool? operator <=(num other) {
+    if (value != null) {
+      return value! <= other;
+    }
+  }
 
 
-  @override
-  double operator %(num other) => value! % other;
+  /// Relational greater than operator.
+  bool? operator >(num other) {
+    if (value != null) {
+      return value! > other;
+    }
+  }
 
 
-  /// Division operator.
-  @override
-  double operator /(num other) => value! / other;
+  /// Relational greater than or equal operator.
+  bool? operator >=(num other) {
+    if (value != null) {
+      return value! >= other;
+    }
+  }
 
 
-  /// Truncating division operator.
+  /// True if the number is the double Not-a-Number value; otherwise, false.
+  bool? get isNaN => value?.isNaN;
+
+  /// True if the number is negative; otherwise, false.
   ///
   ///
-  /// The result of the truncating division `a ~/ b` is equivalent to
-  /// `(a / b).truncate()`.
-  @override
-  int operator ~/(num other) => value! ~/ other;
+  /// Negative numbers are those less than zero, and the double `-0.0`.
+  bool? get isNegative => value?.isNegative;
 
 
-  /// Negate operator. */
-  @override
-  double operator -() => -value!;
+  /// True if the number is positive infinity or negative infinity; otherwise,
+  /// false.
+  bool? get isInfinite => value?.isInfinite;
 
 
-  /// Returns the absolute value of this [double].
-  @override
-  double abs() => value!.abs();
+  /// True if the number is finite; otherwise, false.
+  ///
+  /// The only non-finite numbers are NaN, positive infinity, and
+  /// negative infinity.
+  bool? get isFinite => value?.isFinite;
 
 
-  /// Returns the sign of the double's numerical value.
+  /// Returns the absolute value of this [num].
+  num? abs() => value?.abs();
+
+  /// Returns minus one, zero or plus one depending on the sign and
+  /// numerical value of the number.
   ///
   ///
-  /// Returns -1.0 if the value is less than zero,
-  /// +1.0 if the value is greater than zero,
-  /// and the value itself if it is -0.0, 0.0 or NaN.
-  @override
-  double get sign => value!.sign;
+  /// Returns minus one if the number is less than zero,
+  /// plus one if the number is greater than zero,
+  /// and zero if the number is equal to zero.
+  ///
+  /// Returns NaN if the number is the double NaN value.
+  ///
+  /// Returns a number of the same type as this number.
+  /// For doubles, `-0.0.sign == -0.0`.
+  /// The result satisfies:
+  ///
+  ///     n == n.sign * n.abs()
+  ///
+  /// for all numbers `n` (except NaN, because NaN isn't `==` to itself).
+  num? get sign => value?.sign;
 
 
   /// Returns the integer closest to `this`.
   /// Returns the integer closest to `this`.
   ///
   ///
@@ -338,163 +398,547 @@ class RxDouble extends _BaseRxNum<double?> {
   ///  `(3.5).round() == 4` and `(-3.5).round() == -4`.
   ///  `(3.5).round() == 4` and `(-3.5).round() == -4`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  @override
-  int round() => value!.round();
+  int? round() => value?.round();
 
 
   /// Returns the greatest integer no greater than `this`.
   /// Returns the greatest integer no greater than `this`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  @override
-  int floor() => value!.floor();
+  int? floor() => value?.floor();
 
 
   /// Returns the least integer no smaller than `this`.
   /// Returns the least integer no smaller than `this`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  @override
-  int ceil() => value!.ceil();
+  int? ceil() => value?.ceil();
 
 
   /// Returns the integer obtained by discarding any fractional
   /// Returns the integer obtained by discarding any fractional
   /// digits from `this`.
   /// digits from `this`.
   ///
   ///
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
   /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
-  @override
-  int truncate() => value!.truncate();
+  int? truncate() => value?.truncate();
 
 
-  /// Returns the integer double value closest to `this`.
+  /// Returns the double integer value closest to `this`.
   ///
   ///
   /// Rounds away from zero when there is no closest integer:
   /// Rounds away from zero when there is no closest integer:
   ///  `(3.5).roundToDouble() == 4` and `(-3.5).roundToDouble() == -4`.
   ///  `(3.5).roundToDouble() == 4` and `(-3.5).roundToDouble() == -4`.
   ///
   ///
-  /// If this is already an integer valued double, including `-0.0`, or it is
-  /// not a finite value, the value is returned unmodified.
+  /// If this is already an integer valued double, including `-0.0`, or it is a
+  /// non-finite double value, the value is returned unmodified.
   ///
   ///
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`,
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`,
   /// and `-0.0` is therefore considered closer to negative numbers than `0.0`.
   /// and `-0.0` is therefore considered closer to negative numbers than `0.0`.
   /// This means that for a value, `d` in the range `-0.5 < d < 0.0`,
   /// This means that for a value, `d` in the range `-0.5 < d < 0.0`,
   /// the result is `-0.0`.
   /// the result is `-0.0`.
-  @override
-  double roundToDouble() => value!.roundToDouble();
+  ///
+  /// The result is always a double.
+  /// If this is a numerically large integer, the result may be an infinite
+  /// double.
+  double? roundToDouble() => value?.roundToDouble();
 
 
-  /// Returns the greatest integer double value no greater than `this`.
+  /// Returns the greatest double integer value no greater than `this`.
   ///
   ///
-  /// If this is already an integer valued double, including `-0.0`, or it is
-  /// not a finite value, the value is returned unmodified.
+  /// If this is already an integer valued double, including `-0.0`, or it is a
+  /// non-finite double value, the value is returned unmodified.
   ///
   ///
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
   /// A number `d` in the range `0.0 < d < 1.0` will return `0.0`.
   /// A number `d` in the range `0.0 < d < 1.0` will return `0.0`.
-  @override
-  double floorToDouble() => value!.floorToDouble();
+  ///
+  /// The result is always a double.
+  /// If this is a numerically large integer, the result may be an infinite
+  /// double.
+  double? floorToDouble() => value?.floorToDouble();
 
 
-  /// Returns the least integer double value no smaller than `this`.
+  /// Returns the least double integer value no smaller than `this`.
   ///
   ///
-  /// If this is already an integer valued double, including `-0.0`, or it is
-  /// not a finite value, the value is returned unmodified.
+  /// If this is already an integer valued double, including `-0.0`, or it is a
+  /// non-finite double value, the value is returned unmodified.
   ///
   ///
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
   /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`.
   /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`.
-  @override
-  double ceilToDouble() => value!.ceilToDouble();
+  ///
+  /// The result is always a double.
+  /// If this is a numerically large integer, the result may be an infinite
+  /// double.
+  double? ceilToDouble() => value?.ceilToDouble();
 
 
-  /// Returns the integer double value obtained by discarding any fractional
-  /// digits from `this`.
+  /// Returns the double integer value obtained by discarding any fractional
+  /// digits from the double value of `this`.
   ///
   ///
-  /// If this is already an integer valued double, including `-0.0`, or it is
-  /// not a finite value, the value is returned unmodified.
+  /// If this is already an integer valued double, including `-0.0`, or it is a
+  /// non-finite double value, the value is returned unmodified.
   ///
   ///
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
   /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
   /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`, and
   /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`, and
   /// in the range `0.0 < d < 1.0` it will return 0.0.
   /// in the range `0.0 < d < 1.0` it will return 0.0.
-  @override
-  double truncateToDouble() => value!.truncateToDouble();
-}
-
-class RxInt extends _BaseRxNum<int> {
-  RxInt(int initial) : super(initial);
-
-  /// Addition operator.
-  RxInt operator +(int other) {
-    value = value + other;
-    return this;
-  }
-
-  /// Subtraction operator.
-  RxInt operator -(int other) {
-    value = value - other;
-    return this;
-  }
-
-  /// Bit-wise and operator.
-  ///
-  /// Treating both `this` and [other] as sufficiently large two's component
-  /// integers, the result is a number with only the bits set that are set in
-  /// both `this` and [other]
   ///
   ///
-  /// If both operands are negative, the result is negative, otherwise
-  /// the result is non-negative.
-  int operator &(int other) => value & other;
+  /// The result is always a double.
+  /// If this is a numerically large integer, the result may be an infinite
+  /// double.
+  double? truncateToDouble() => value?.truncateToDouble();
 
 
-  /// Bit-wise or operator.
+  /// Returns this [num] clamped to be in the range [lowerLimit]-[upperLimit].
   ///
   ///
-  /// Treating both `this` and [other] as sufficiently large two's component
-  /// integers, the result is a number with the bits set that are set in either
-  /// of `this` and [other]
+  /// The comparison is done using [compareTo] and therefore takes `-0.0` into
+  /// account. This also implies that [double.nan] is treated as the maximal
+  /// double value.
   ///
   ///
-  /// If both operands are non-negative, the result is non-negative,
-  /// otherwise the result is negative.
-  int operator |(int other) => value | other;
+  /// The arguments [lowerLimit] and [upperLimit] must form a valid range where
+  /// `lowerLimit.compareTo(upperLimit) <= 0`.
+  num? clamp(num lowerLimit, num upperLimit) =>
+      value?.clamp(lowerLimit, upperLimit);
 
 
-  /// Bit-wise exclusive-or operator.
-  ///
-  /// Treating both `this` and [other] as sufficiently large two's component
-  /// integers, the result is a number with the bits set that are set in one,
-  /// but not both, of `this` and [other]
-  ///
-  /// If the operands have the same sign, the result is non-negative,
-  /// otherwise the result is negative.
-  int operator ^(int other) => value ^ other;
+  /// Truncates this [num] to an integer and returns the result as an [int]. */
+  int? toInt() => value?.toInt();
 
 
-  /// The bit-wise negate operator.
-  ///
-  /// Treating `this` as a sufficiently large two's component integer,
-  /// the result is a number with the opposite bits set.
+  /// Return this [num] as a [double].
   ///
   ///
-  /// This maps any integer `x` to `-x - 1`.
-  int operator ~() => ~value;
+  /// If the number is not representable as a [double], an
+  /// approximation is returned. For numerically large integers, the
+  /// approximation may be infinite.
+  double? toDouble() => value?.toDouble();
 
 
-  /// Shift the bits of this integer to the left by [shiftAmount].
+  /// Returns a decimal-point string-representation of `this`.
   ///
   ///
-  /// Shifting to the left makes the number larger, effectively multiplying
-  /// the number by `pow(2, shiftIndex)`.
+  /// Converts `this` to a [double] before computing the string representation.
   ///
   ///
-  /// There is no limit on the size of the result. It may be relevant to
-  /// limit intermediate values by using the "and" operator with a suitable
-  /// mask.
+  /// If the absolute value of `this` is greater or equal to `10^21` then this
+  /// methods returns an exponential representation computed by
+  /// `this.toStringAsExponential()`. Otherwise the result
+  /// is the closest string representation with exactly [fractionDigits] digits
+  /// after the decimal point. If [fractionDigits] equals 0 then the decimal
+  /// point is omitted.
   ///
   ///
-  /// It is an error if [shiftAmount] is negative.
-  int operator <<(int shiftAmount) => value << shiftAmount;
-
-  /// Shift the bits of this integer to the right by [shiftAmount].
+  /// The parameter [fractionDigits] must be an integer satisfying:
+  /// `0 <= fractionDigits <= 20`.
   ///
   ///
-  /// Shifting to the right makes the number smaller and drops the least
-  /// significant bits, effectively doing an integer division by
-  ///`pow(2, shiftIndex)`.
+  /// Examples:
   ///
   ///
-  /// It is an error if [shiftAmount] is negative.
-  int operator >>(int shiftAmount) => value >> shiftAmount;
+  ///     1.toStringAsFixed(3);  // 1.000
+  ///     (4321.12345678).toStringAsFixed(3);  // 4321.123
+  ///     (4321.12345678).toStringAsFixed(5);  // 4321.12346
+  ///     123456789012345.toStringAsFixed(3);  // 123456789012345.000
+  ///     10000000000000000.toStringAsFixed(4); // 10000000000000000.0000
+  ///     5.25.toStringAsFixed(0); // 5
+  String? toStringAsFixed(int fractionDigits) =>
+      value?.toStringAsFixed(fractionDigits);
 
 
-  /// Returns this integer to the power of [exponent] modulo [modulus].
+  /// Returns an exponential string-representation of `this`.
   ///
   ///
-  /// The [exponent] must be non-negative and [modulus] must be
-  /// positive.
-  int modPow(int exponent, int modulus) => value.modPow(exponent, modulus);
-
-  /// Returns the modular multiplicative inverse of this integer
-  /// modulo [modulus].
+  /// Converts `this` to a [double] before computing the string representation.
   ///
   ///
-  /// The [modulus] must be positive.
+  /// If [fractionDigits] is given then it must be an integer satisfying:
+  /// `0 <= fractionDigits <= 20`. In this case the string contains exactly
+  /// [fractionDigits] after the decimal point. Otherwise, without the
+  /// parameter, the returned string uses the shortest number of digits that
+  /// accurately represent [this].
   ///
   ///
-  /// It is an error if no modular inverse exists.
-  int modInverse(int modulus) => value.modInverse(modulus);
+  /// If [fractionDigits] equals 0 then the decimal point is omitted.
+  /// Examples:
+  ///
+  ///     1.toStringAsExponential();       // 1e+0
+  ///     1.toStringAsExponential(3);      // 1.000e+0
+  ///     123456.toStringAsExponential();  // 1.23456e+5
+  ///     123456.toStringAsExponential(3); // 1.235e+5
+  ///     123.toStringAsExponential(0);    // 1e+2
+  String? toStringAsExponential([int? fractionDigits]) =>
+      value?.toStringAsExponential(fractionDigits);
+
+  /// Converts `this` to a double and returns a string representation with
+  /// exactly [precision] significant digits.
+  ///
+  /// The parameter [precision] must be an integer satisfying:
+  /// `1 <= precision <= 21`.
+  ///
+  /// Examples:
+  ///
+  ///     1.toStringAsPrecision(2);       // 1.0
+  ///     1e15.toStringAsPrecision(3);    // 1.00e+15
+  ///     1234567.toStringAsPrecision(3); // 1.23e+6
+  ///     1234567.toStringAsPrecision(9); // 1234567.00
+  ///     12345678901234567890.toStringAsPrecision(20); // 12345678901234567168
+  ///     12345678901234567890.toStringAsPrecision(14); // 1.2345678901235e+19
+  ///     0.00000012345.toStringAsPrecision(15); // 1.23450000000000e-7
+  ///     0.0000012345.toStringAsPrecision(15);  // 0.00000123450000000000
+  String? toStringAsPrecision(int precision) =>
+      value?.toStringAsPrecision(precision);
+}
+
+class RxNum extends Rx<num> {
+  RxNum(num initial) : super(initial);
+
+  num operator +(num other) {
+    value += other;
+    return value;
+  }
+
+  /// Subtraction operator.
+  num operator -(num other) {
+    value -= other;
+    return value;
+  }
+}
+
+class RxnNum extends Rx<num?> {
+  RxnNum(num initial) : super(initial);
+
+  num? operator +(num other) {
+    if (value != null) {
+      value = value! + other;
+      return value;
+    }
+  }
+
+  /// Subtraction operator.
+  num? operator -(num other) {
+    if (value != null) {
+      value = value! - other;
+      return value;
+    }
+  }
+}
+
+extension RxDoubleExt on Rx<double> {
+  /// Addition operator.
+  Rx<double> operator +(num other) {
+    value = value + other;
+    return this;
+  }
+
+  /// Subtraction operator.
+  Rx<double> operator -(num other) {
+    value = value - other;
+    return this;
+  }
+
+  /// Multiplication operator.
+  double operator *(num other) => value * other;
+
+  double operator %(num other) => value % other;
+
+  /// Division operator.
+  double operator /(num other) => value / other;
+
+  /// Truncating division operator.
+  ///
+  /// The result of the truncating division `a ~/ b` is equivalent to
+  /// `(a / b).truncate()`.
+  int operator ~/(num other) => value ~/ other;
+
+  /// Negate operator. */
+  double operator -() => -value;
+
+  /// Returns the absolute value of this [double].
+  double abs() => value.abs();
+
+  /// Returns the sign of the double's numerical value.
+  ///
+  /// Returns -1.0 if the value is less than zero,
+  /// +1.0 if the value is greater than zero,
+  /// and the value itself if it is -0.0, 0.0 or NaN.
+  double get sign => value.sign;
+
+  /// Returns the integer closest to `this`.
+  ///
+  /// Rounds away from zero when there is no closest integer:
+  ///  `(3.5).round() == 4` and `(-3.5).round() == -4`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int round() => value.round();
+
+  /// Returns the greatest integer no greater than `this`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int floor() => value.floor();
+
+  /// Returns the least integer no smaller than `this`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int ceil() => value.ceil();
+
+  /// Returns the integer obtained by discarding any fractional
+  /// digits from `this`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int truncate() => value.truncate();
+
+  /// Returns the integer double value closest to `this`.
+  ///
+  /// Rounds away from zero when there is no closest integer:
+  ///  `(3.5).roundToDouble() == 4` and `(-3.5).roundToDouble() == -4`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`,
+  /// and `-0.0` is therefore considered closer to negative numbers than `0.0`.
+  /// This means that for a value, `d` in the range `-0.5 < d < 0.0`,
+  /// the result is `-0.0`.
+  double roundToDouble() => value.roundToDouble();
+
+  /// Returns the greatest integer double value no greater than `this`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
+  /// A number `d` in the range `0.0 < d < 1.0` will return `0.0`.
+  double floorToDouble() => value.floorToDouble();
+
+  /// Returns the least integer double value no smaller than `this`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
+  /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`.
+  double ceilToDouble() => value.ceilToDouble();
+
+  /// Returns the integer double value obtained by discarding any fractional
+  /// digits from `this`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
+  /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`, and
+  /// in the range `0.0 < d < 1.0` it will return 0.0.
+  double truncateToDouble() => value.truncateToDouble();
+}
+
+extension RxnDoubleExt on Rx<double?> {
+  /// Addition operator.
+  Rx<double?>? operator +(num other) {
+    if (value != null) {
+      value = value! + other;
+      return this;
+    }
+  }
+
+  /// Subtraction operator.
+  Rx<double?>? operator -(num other) {
+    if (value != null) {
+      value = value! + other;
+      return this;
+    }
+  }
+
+  /// Multiplication operator.
+  double? operator *(num other) {
+    if (value != null) {
+      return value! * other;
+    }
+  }
+
+  double? operator %(num other) {
+    if (value != null) {
+      return value! % other;
+    }
+  }
+
+  /// Division operator.
+  double? operator /(num other) {
+    if (value != null) {
+      return value! / other;
+    }
+  }
+
+  /// Truncating division operator.
+  ///
+  /// The result of the truncating division `a ~/ b` is equivalent to
+  /// `(a / b).truncate()`.
+  int? operator ~/(num other) {
+    if (value != null) {
+      return value! ~/ other;
+    }
+  }
+
+  /// Negate operator. */
+  double? operator -() {
+    if (value != null) {
+      return -value!;
+    }
+  }
+
+  /// Returns the absolute value of this [double].
+  double? abs() {
+    return value?.abs();
+  }
+
+  /// Returns the sign of the double's numerical value.
+  ///
+  /// Returns -1.0 if the value is less than zero,
+  /// +1.0 if the value is greater than zero,
+  /// and the value itself if it is -0.0, 0.0 or NaN.
+  double? get sign => value?.sign;
+
+  /// Returns the integer closest to `this`.
+  ///
+  /// Rounds away from zero when there is no closest integer:
+  ///  `(3.5).round() == 4` and `(-3.5).round() == -4`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int? round() => value?.round();
+
+  /// Returns the greatest integer no greater than `this`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int? floor() => value?.floor();
+
+  /// Returns the least integer no smaller than `this`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int? ceil() => value?.ceil();
+
+  /// Returns the integer obtained by discarding any fractional
+  /// digits from `this`.
+  ///
+  /// If `this` is not finite (`NaN` or infinity), throws an [UnsupportedError].
+  int? truncate() => value?.truncate();
+
+  /// Returns the integer double value closest to `this`.
+  ///
+  /// Rounds away from zero when there is no closest integer:
+  ///  `(3.5).roundToDouble() == 4` and `(-3.5).roundToDouble() == -4`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`,
+  /// and `-0.0` is therefore considered closer to negative numbers than `0.0`.
+  /// This means that for a value, `d` in the range `-0.5 < d < 0.0`,
+  /// the result is `-0.0`.
+  double? roundToDouble() => value?.roundToDouble();
+
+  /// Returns the greatest integer double value no greater than `this`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
+  /// A number `d` in the range `0.0 < d < 1.0` will return `0.0`.
+  double? floorToDouble() => value?.floorToDouble();
+
+  /// Returns the least integer double value no smaller than `this`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
+  /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`.
+  double? ceilToDouble() => value?.ceilToDouble();
+
+  /// Returns the integer double value obtained by discarding any fractional
+  /// digits from `this`.
+  ///
+  /// If this is already an integer valued double, including `-0.0`, or it is
+  /// not a finite value, the value is returned unmodified.
+  ///
+  /// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
+  /// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`, and
+  /// in the range `0.0 < d < 1.0` it will return 0.0.
+  double? truncateToDouble() => value?.truncateToDouble();
+}
+
+class RxDouble extends Rx<double> {
+  RxDouble(double initial) : super(initial);
+}
+
+class RxnDouble extends Rx<double?> {
+  RxnDouble([double? initial]) : super(initial);
+}
+
+class RxInt extends Rx<int> {
+  RxInt(int initial) : super(initial);
+}
+
+class RxnInt extends Rx<int?> {
+  RxnInt([int? initial]) : super(initial);
+}
+
+extension RxIntExt on Rx<int> {
+  /// Addition operator.
+  Rx<int> operator +(int other) {
+    value = value + other;
+    return this;
+  }
+
+  /// Subtraction operator.
+  Rx<int> operator -(int other) {
+    value = value - other;
+    return this;
+  }
+
+  /// Bit-wise and operator.
+  ///
+  /// Treating both `this` and [other] as sufficiently large two's component
+  /// integers, the result is a number with only the bits set that are set in
+  /// both `this` and [other]
+  ///
+  /// If both operands are negative, the result is negative, otherwise
+  /// the result is non-negative.
+  int operator &(int other) => value & other;
+
+  /// Bit-wise or operator.
+  ///
+  /// Treating both `this` and [other] as sufficiently large two's component
+  /// integers, the result is a number with the bits set that are set in either
+  /// of `this` and [other]
+  ///
+  /// If both operands are non-negative, the result is non-negative,
+  /// otherwise the result is negative.
+  int operator |(int other) => value | other;
+
+  /// Bit-wise exclusive-or operator.
+  ///
+  /// Treating both `this` and [other] as sufficiently large two's component
+  /// integers, the result is a number with the bits set that are set in one,
+  /// but not both, of `this` and [other]
+  ///
+  /// If the operands have the same sign, the result is non-negative,
+  /// otherwise the result is negative.
+  int operator ^(int other) => value ^ other;
+
+  /// The bit-wise negate operator.
+  ///
+  /// Treating `this` as a sufficiently large two's component integer,
+  /// the result is a number with the opposite bits set.
+  ///
+  /// This maps any integer `x` to `-x - 1`.
+  int operator ~() => ~value;
+
+  /// Shift the bits of this integer to the left by [shiftAmount].
+  ///
+  /// Shifting to the left makes the number larger, effectively multiplying
+  /// the number by `pow(2, shiftIndex)`.
+  ///
+  /// There is no limit on the size of the result. It may be relevant to
+  /// limit intermediate values by using the "and" operator with a suitable
+  /// mask.
+  ///
+  /// It is an error if [shiftAmount] is negative.
+  int operator <<(int shiftAmount) => value << shiftAmount;
+
+  /// Shift the bits of this integer to the right by [shiftAmount].
+  ///
+  /// Shifting to the right makes the number smaller and drops the least
+  /// significant bits, effectively doing an integer division by
+  ///`pow(2, shiftIndex)`.
+  ///
+  /// It is an error if [shiftAmount] is negative.
+  int operator >>(int shiftAmount) => value >> shiftAmount;
+
+  /// Returns this integer to the power of [exponent] modulo [modulus].
+  ///
+  /// The [exponent] must be non-negative and [modulus] must be
+  /// positive.
+  int modPow(int exponent, int modulus) => value.modPow(exponent, modulus);
+
+  /// Returns the modular multiplicative inverse of this integer
+  /// modulo [modulus].
+  ///
+  /// The [modulus] must be positive.
+  ///
+  /// It is an error if no modular inverse exists.
+  int modInverse(int modulus) => value.modInverse(modulus);
 
 
   /// Returns the greatest common divisor of this integer and [other].
   /// Returns the greatest common divisor of this integer and [other].
   ///
   ///
@@ -593,51 +1037,293 @@ class RxInt extends _BaseRxNum<int> {
   ///
   ///
   /// The result of negating an integer always has the opposite sign, except
   /// The result of negating an integer always has the opposite sign, except
   /// for zero, which is its own negation.
   /// for zero, which is its own negation.
-  @override
   int operator -() => -value;
   int operator -() => -value;
 
 
   /// Returns the absolute value of this integer.
   /// Returns the absolute value of this integer.
   ///
   ///
   /// For any integer `x`, the result is the same as `x < 0 ? -x : x`.
   /// For any integer `x`, the result is the same as `x < 0 ? -x : x`.
-  @override
   int abs() => value.abs();
   int abs() => value.abs();
 
 
   /// Returns the sign of this integer.
   /// Returns the sign of this integer.
   ///
   ///
   /// Returns 0 for zero, -1 for values less than zero and
   /// Returns 0 for zero, -1 for values less than zero and
   /// +1 for values greater than zero.
   /// +1 for values greater than zero.
-  @override
   int get sign => value.sign;
   int get sign => value.sign;
 
 
   /// Returns `this`.
   /// Returns `this`.
-  @override
   int round() => value.round();
   int round() => value.round();
 
 
   /// Returns `this`.
   /// Returns `this`.
-  @override
   int floor() => value.floor();
   int floor() => value.floor();
 
 
   /// Returns `this`.
   /// Returns `this`.
-  @override
   int ceil() => value.ceil();
   int ceil() => value.ceil();
 
 
   /// Returns `this`.
   /// Returns `this`.
-  @override
   int truncate() => value.truncate();
   int truncate() => value.truncate();
 
 
   /// Returns `this.toDouble()`.
   /// Returns `this.toDouble()`.
-  @override
   double roundToDouble() => value.roundToDouble();
   double roundToDouble() => value.roundToDouble();
 
 
   /// Returns `this.toDouble()`.
   /// Returns `this.toDouble()`.
-  @override
   double floorToDouble() => value.floorToDouble();
   double floorToDouble() => value.floorToDouble();
 
 
   /// Returns `this.toDouble()`.
   /// Returns `this.toDouble()`.
-  @override
   double ceilToDouble() => value.ceilToDouble();
   double ceilToDouble() => value.ceilToDouble();
 
 
   /// Returns `this.toDouble()`.
   /// Returns `this.toDouble()`.
-  @override
   double truncateToDouble() => value.truncateToDouble();
   double truncateToDouble() => value.truncateToDouble();
 }
 }
+
+extension RxnIntExt on Rx<int?> {
+  /// Addition operator.
+  Rx<int?>? operator +(int other) {
+    if (value != null) {
+      value = value! + other;
+      return this;
+    }
+  }
+
+  /// Subtraction operator.
+  Rx<int?>? operator -(int other) {
+    if (value != null) {
+      value = value! - other;
+      return this;
+    }
+  }
+
+  /// Bit-wise and operator.
+  ///
+  /// Treating both `this` and [other] as sufficiently large two's component
+  /// integers, the result is a number with only the bits set that are set in
+  /// both `this` and [other]
+  ///
+  /// If both operands are negative, the result is negative, otherwise
+  /// the result is non-negative.
+  int? operator &(int other) {
+    if (value != null) {
+      return value! & other;
+    }
+  }
+
+  /// Bit-wise or operator.
+  ///
+  /// Treating both `this` and [other] as sufficiently large two's component
+  /// integers, the result is a number with the bits set that are set in either
+  /// of `this` and [other]
+  ///
+  /// If both operands are non-negative, the result is non-negative,
+  /// otherwise the result is negative.
+  int? operator |(int other) {
+    if (value != null) {
+      return value! | other;
+    }
+  }
+
+  /// Bit-wise exclusive-or operator.
+  ///
+  /// Treating both `this` and [other] as sufficiently large two's component
+  /// integers, the result is a number with the bits set that are set in one,
+  /// but not both, of `this` and [other]
+  ///
+  /// If the operands have the same sign, the result is non-negative,
+  /// otherwise the result is negative.
+  int? operator ^(int other) {
+    if (value != null) {
+      return value! ^ other;
+    }
+  }
+
+  /// The bit-wise negate operator.
+  ///
+  /// Treating `this` as a sufficiently large two's component integer,
+  /// the result is a number with the opposite bits set.
+  ///
+  /// This maps any integer `x` to `-x - 1`.
+  int? operator ~() {
+    if (value != null) {
+      return ~value!;
+    }
+  }
+
+  /// Shift the bits of this integer to the left by [shiftAmount].
+  ///
+  /// Shifting to the left makes the number larger, effectively multiplying
+  /// the number by `pow(2, shiftIndex)`.
+  ///
+  /// There is no limit on the size of the result. It may be relevant to
+  /// limit intermediate values by using the "and" operator with a suitable
+  /// mask.
+  ///
+  /// It is an error if [shiftAmount] is negative.
+  int? operator <<(int shiftAmount) {
+    if (value != null) {
+      return value! << shiftAmount;
+    }
+  }
+
+  /// Shift the bits of this integer to the right by [shiftAmount].
+  ///
+  /// Shifting to the right makes the number smaller and drops the least
+  /// significant bits, effectively doing an integer division by
+  ///`pow(2, shiftIndex)`.
+  ///
+  /// It is an error if [shiftAmount] is negative.
+  int? operator >>(int shiftAmount) {
+    if (value != null) {
+      return value! >> shiftAmount;
+    }
+  }
+
+  /// Returns this integer to the power of [exponent] modulo [modulus].
+  ///
+  /// The [exponent] must be non-negative and [modulus] must be
+  /// positive.
+  int? modPow(int exponent, int modulus) => value?.modPow(exponent, modulus);
+
+  /// Returns the modular multiplicative inverse of this integer
+  /// modulo [modulus].
+  ///
+  /// The [modulus] must be positive.
+  ///
+  /// It is an error if no modular inverse exists.
+  int? modInverse(int modulus) => value?.modInverse(modulus);
+
+  /// Returns the greatest common divisor of this integer and [other].
+  ///
+  /// If either number is non-zero, the result is the numerically greatest
+  /// integer dividing both `this` and `other`.
+  ///
+  /// The greatest common divisor is independent of the order,
+  /// so `x.gcd(y)` is  always the same as `y.gcd(x)`.
+  ///
+  /// For any integer `x`, `x.gcd(x)` is `x.abs()`.
+  ///
+  /// If both `this` and `other` is zero, the result is also zero.
+  int? gcd(int other) => value?.gcd(other);
+
+  /// Returns true if and only if this integer is even.
+  bool? get isEven => value?.isEven;
+
+  /// Returns true if and only if this integer is odd.
+  bool? get isOdd => value?.isOdd;
+
+  /// Returns the minimum number of bits required to store this integer.
+  ///
+  /// The number of bits excludes the sign bit, which gives the natural length
+  /// for non-negative (unsigned) values.  Negative values are complemented to
+  /// return the bit position of the first bit that differs from the sign bit.
+  ///
+  /// To find the number of bits needed to store the value as a signed value,
+  /// add one, i.e. use `x.bitLength + 1`.
+  /// ```
+  /// x.bitLength == (-x-1).bitLength
+  ///
+  /// 3.bitLength == 2;     // 00000011
+  /// 2.bitLength == 2;     // 00000010
+  /// 1.bitLength == 1;     // 00000001
+  /// 0.bitLength == 0;     // 00000000
+  /// (-1).bitLength == 0;  // 11111111
+  /// (-2).bitLength == 1;  // 11111110
+  /// (-3).bitLength == 2;  // 11111101
+  /// (-4).bitLength == 2;  // 11111100
+  /// ```
+  int? get bitLength => value?.bitLength;
+
+  /// Returns the least significant [width] bits of this integer as a
+  /// non-negative number (i.e. unsigned representation).  The returned value
+  /// has zeros in all bit positions higher than [width].
+  /// ```
+  /// (-1).toUnsigned(5) == 31   // 11111111  ->  00011111
+  /// ```
+  /// This operation can be used to simulate arithmetic from low level
+  /// languages.
+  /// For example, to increment an 8 bit quantity:
+  /// ```
+  /// q = (q + 1).toUnsigned(8);
+  /// ```
+  /// `q` will count from `0` up to `255` and then wrap around to `0`.
+  ///
+  /// If the input fits in [width] bits without truncation, the result is the
+  /// same as the input.  The minimum width needed to avoid truncation of `x` is
+  /// given by `x.bitLength`, i.e.
+  /// ```
+  /// x == x.toUnsigned(x.bitLength);
+  /// ```
+  int? toUnsigned(int width) => value?.toUnsigned(width);
+
+  /// Returns the least significant [width] bits of this integer, extending the
+  /// highest retained bit to the sign.  This is the same as truncating the
+  /// value to fit in [width] bits using an signed 2-s complement
+  /// representation.
+  /// The returned value has the same bit value in all positions higher than
+  /// [width].
+  ///
+  /// ```
+  ///                                V--sign bit-V
+  /// 16.toSigned(5) == -16   //  00010000 -> 11110000
+  /// 239.toSigned(5) == 15   //  11101111 -> 00001111
+  ///                                ^           ^
+  /// ```
+  /// This operation can be used to simulate arithmetic from low level
+  /// languages.
+  /// For example, to increment an 8 bit signed quantity:
+  /// ```
+  /// q = (q + 1).toSigned(8);
+  /// ```
+  /// `q` will count from `0` up to `127`, wrap to `-128` and count back up to
+  /// `127`.
+  ///
+  /// If the input value fits in [width] bits without truncation, the result is
+  /// the same as the input.  The minimum width needed to avoid truncation
+  /// of `x` is `x.bitLength + 1`, i.e.
+  /// ```
+  /// x == x.toSigned(x.bitLength + 1);
+  /// ```
+  int? toSigned(int width) => value?.toSigned(width);
+
+  /// Return the negative value of this integer.
+  ///
+  /// The result of negating an integer always has the opposite sign, except
+  /// for zero, which is its own negation.
+  int? operator -() {
+    if (value != null) {
+      return -value!;
+    }
+  }
+
+  /// Returns the absolute value of this integer.
+  ///
+  /// For any integer `x`, the result is the same as `x < 0 ? -x : x`.
+  int? abs() => value?.abs();
+
+  /// Returns the sign of this integer.
+  ///
+  /// Returns 0 for zero, -1 for values less than zero and
+  /// +1 for values greater than zero.
+  int? get sign => value?.sign;
+
+  /// Returns `this`.
+  int? round() => value?.round();
+
+  /// Returns `this`.
+  int? floor() => value?.floor();
+
+  /// Returns `this`.
+  int? ceil() => value?.ceil();
+
+  /// Returns `this`.
+  int? truncate() => value?.truncate();
+
+  /// Returns `this.toDouble()`.
+  double? roundToDouble() => value?.roundToDouble();
+
+  /// Returns `this.toDouble()`.
+  double? floorToDouble() => value?.floorToDouble();
+
+  /// Returns `this.toDouble()`.
+  double? ceilToDouble() => value?.ceilToDouble();
+
+  /// Returns `this.toDouble()`.
+  double? truncateToDouble() => value?.truncateToDouble();
+}

+part of rx_types;
+
+extension RxStringExt on Rx<String> {
+  String operator +(String val) => _value + val;
+
+  int compareTo(String other) {
+    return value.compareTo(other);
+  }
+
+  /// Returns true if this string ends with [other]. For example:
+  ///
+  ///     'Dart'.endsWith('t'); // true
+  bool endsWith(String other) {
+    return value.endsWith(other);
+  }
+
+  /// Returns true if this string starts with a match of [pattern].
+  bool startsWith(Pattern pattern, [int index = 0]) {
+    return value.startsWith(pattern, index);
+  }
+
+  /// Returns the position of the first match of [pattern] in this string
+  int indexOf(Pattern pattern, [int start = 0]) {
+    return value.indexOf(pattern, start);
+  }
+
+  /// Returns the starting position of the last match [pattern] in this string,
+  /// searching backward starting at [start], inclusive:
+  int lastIndexOf(Pattern pattern, [int? start]) {
+    return value.lastIndexOf(pattern, start);
+  }
+
+  /// Returns true if this string is empty.
+  bool get isEmpty => value.isEmpty;
+
+  /// Returns true if this string is not empty.
+  bool get isNotEmpty => !isEmpty;
+
+  /// Returns the substring of this string that extends from [startIndex],
+  /// inclusive, to [endIndex], exclusive
+  String substring(int startIndex, [int? endIndex]) {
+    return value.substring(startIndex, endIndex);
+  }
+
+  /// Returns the string without any leading and trailing whitespace.
+  String trim() {
+    return value.trim();
+  }
+
+  /// Returns the string without any leading whitespace.
+  ///
+  /// As [trim], but only removes leading whitespace.
+  String trimLeft() {
+    return value.trimLeft();
+  }
+
+  /// Returns the string without any trailing whitespace.
+  ///
+  /// As [trim], but only removes trailing whitespace.
+  String trimRight() {
+    return value.trimRight();
+  }
+
+  /// Pads this string on the left if it is shorter than [width].
+  ///
+  /// Return a new string that prepends [padding] onto this string
+  /// one time for each position the length is less than [width].
+  String padLeft(int width, [String padding = ' ']) {
+    return value.padLeft(width, padding);
+  }
+
+  /// Pads this string on the right if it is shorter than [width].
+
+  /// Return a new string that appends [padding] after this string
+  /// one time for each position the length is less than [width].
+  String padRight(int width, [String padding = ' ']) {
+    return value.padRight(width, padding);
+  }
+
+  /// Returns true if this string contains a match of [other]:
+  bool contains(Pattern other, [int startIndex = 0]) {
+    return value.contains(other, startIndex);
+  }
+
+  /// Replaces all substrings that match [from] with [replace].
+  String replaceAll(Pattern from, String replace) {
+    return value.replaceAll(from, replace);
+  }
+
+  /// Splits the string at matches of [pattern] and returns a list
+  /// of substrings.
+  List<String> split(Pattern pattern) {
+    return value.split(pattern);
+  }
+
+  /// Returns an unmodifiable list of the UTF-16 code units of this string.
+  List<int> get codeUnits => value.codeUnits;
+
+  /// Returns an [Iterable] of Unicode code-points of this string.
+  ///
+  /// If the string contains surrogate pairs, they are combined and returned
+  /// as one integer by this iterator. Unmatched surrogate halves are treated
+  /// like valid 16-bit code-units.
+  Runes get runes => value.runes;
+
+  /// Converts all characters in this string to lower case.
+  /// If the string is already in all lower case, this method returns `this`.
+  String toLowerCase() {
+    return value.toLowerCase();
+  }
+
+  /// Converts all characters in this string to upper case.
+  /// If the string is already in all upper case, this method returns `this`.
+  String toUpperCase() {
+    return value.toUpperCase();
+  }
+
+  Iterable<Match> allMatches(String string, [int start = 0]) {
+    return value.allMatches(string, start);
+  }
+
+  Match? matchAsPrefix(String string, [int start = 0]) {
+    return value.matchAsPrefix(string, start);
+  }
+}
+
+extension RxnStringExt on Rx<String?> {
+  String operator +(String val) => (_value ?? '') + val;
+
+  int? compareTo(String other) {
+    return value?.compareTo(other);
+  }
+
+  /// Returns true if this string ends with [other]. For example:
+  ///
+  ///     'Dart'.endsWith('t'); // true
+  bool? endsWith(String other) {
+    return value?.endsWith(other);
+  }
+
+  /// Returns true if this string starts with a match of [pattern].
+  bool? startsWith(Pattern pattern, [int index = 0]) {
+    return value?.startsWith(pattern, index);
+  }
+
+  /// Returns the position of the first match of [pattern] in this string
+  int? indexOf(Pattern pattern, [int start = 0]) {
+    return value?.indexOf(pattern, start);
+  }
+
+  /// Returns the starting position of the last match [pattern] in this string,
+  /// searching backward starting at [start], inclusive:
+  int? lastIndexOf(Pattern pattern, [int? start]) {
+    return value?.lastIndexOf(pattern, start);
+  }
+
+  /// Returns true if this string is empty.
+  bool? get isEmpty => value?.isEmpty;
+
+  /// Returns true if this string is not empty.
+  bool? get isNotEmpty => value?.isNotEmpty;
+
+  /// Returns the substring of this string that extends from [startIndex],
+  /// inclusive, to [endIndex], exclusive
+  String? substring(int startIndex, [int? endIndex]) {
+    return value?.substring(startIndex, endIndex);
+  }
+
+  /// Returns the string without any leading and trailing whitespace.
+  String? trim() {
+    return value?.trim();
+  }
+
+  /// Returns the string without any leading whitespace.
+  ///
+  /// As [trim], but only removes leading whitespace.
+  String? trimLeft() {
+    return value?.trimLeft();
+  }
+
+  /// Returns the string without any trailing whitespace.
+  ///
+  /// As [trim], but only removes trailing whitespace.
+  String? trimRight() {
+    return value?.trimRight();
+  }
+
+  /// Pads this string on the left if it is shorter than [width].
+  ///
+  /// Return a new string that prepends [padding] onto this string
+  /// one time for each position the length is less than [width].
+  String? padLeft(int width, [String padding = ' ']) {
+    return value?.padLeft(width, padding);
+  }
+
+  /// Pads this string on the right if it is shorter than [width].
+
+  /// Return a new string that appends [padding] after this string
+  /// one time for each position the length is less than [width].
+  String? padRight(int width, [String padding = ' ']) {
+    return value?.padRight(width, padding);
+  }
+
+  /// Returns true if this string contains a match of [other]:
+  bool? contains(Pattern other, [int startIndex = 0]) {
+    return value?.contains(other, startIndex);
+  }
+
+  /// Replaces all substrings that match [from] with [replace].
+  String? replaceAll(Pattern from, String replace) {
+    return value?.replaceAll(from, replace);
+  }
+
+  /// Splits the string at matches of [pattern] and returns a list
+  /// of substrings.
+  List<String>? split(Pattern pattern) {
+    return value?.split(pattern);
+  }
+
+  /// Returns an unmodifiable list of the UTF-16 code units of this string.
+  List<int>? get codeUnits => value?.codeUnits;
+
+  /// Returns an [Iterable] of Unicode code-points of this string.
+  ///
+  /// If the string contains surrogate pairs, they are combined and returned
+  /// as one integer by this iterator. Unmatched surrogate halves are treated
+  /// like valid 16-bit code-units.
+  Runes? get runes => value?.runes;
+
+  /// Converts all characters in this string to lower case.
+  /// If the string is already in all lower case, this method returns `this`.
+  String? toLowerCase() {
+    return value?.toLowerCase();
+  }
+
+  /// Converts all characters in this string to upper case.
+  /// If the string is already in all upper case, this method returns `this`.
+  String? toUpperCase() {
+    return value?.toUpperCase();
+  }
+
+  Iterable<Match>? allMatches(String string, [int start = 0]) {
+    return value?.allMatches(string, start);
+  }
+
+  Match? matchAsPrefix(String string, [int start = 0]) {
+    return value?.matchAsPrefix(string, start);
+  }
+}
+
+/// Rx class for `String` Type.
+class RxString extends Rx<String> implements Comparable<String>, Pattern {
+  RxString(String initial) : super(initial);
+
+  @override
+  Iterable<Match> allMatches(String string, [int start = 0]) {
+    return value.allMatches(string, start);
+  }
+
+  @override
+  Match? matchAsPrefix(String string, [int start = 0]) {
+    return value.matchAsPrefix(string, start);
+  }
+
+  @override
+  int compareTo(String other) {
+    return value.compareTo(other);
+  }
+}
+
+/// Rx class for `String` Type.
+class RxnString extends Rx<String?> implements Comparable<String>, Pattern {
+  RxnString(String? initial) : super(initial);
+
+  @override
+  Iterable<Match> allMatches(String string, [int start = 0]) {
+    return value!.allMatches(string, start);
+  }
+
+  @override
+  Match? matchAsPrefix(String string, [int start = 0]) {
+    return value!.matchAsPrefix(string, start);
+  }
+
+  @override
+  int compareTo(String other) {
+    return value!.compareTo(other);
+  }
+}

@@ -10,6 +10,7 @@ import '../rx_typedefs/rx_typedefs.dart';
 part 'rx_core/rx_impl.dart';
 part 'rx_core/rx_impl.dart';
 part 'rx_core/rx_interface.dart';
 part 'rx_core/rx_interface.dart';
 part 'rx_core/rx_num.dart';
 part 'rx_core/rx_num.dart';
+part 'rx_core/rx_string.dart';
 
 
 part 'rx_iterables/rx_list.dart';
 part 'rx_iterables/rx_list.dart';
 part 'rx_iterables/rx_set.dart';
 part 'rx_iterables/rx_set.dart';

@@ -104,24 +104,3 @@ class ObxValue<T extends RxInterface> extends ObxWidget {
   @override
   @override
   Widget build() => builder(data);
   Widget build() => builder(data);
 }
 }
-
-/// Similar to Obx, but manages a local state.
-/// Pass the initial data in constructor.
-/// Useful for simple local states, like toggles, visibility, themes,
-/// button states, etc.
-///  Sample:
-///    ObxValue((data) => Switch(
-///      value: data.value,
-///      onChanged: (flag) => data.value = flag,
-///    ),
-///    false.obs,
-///   ),
-class RxValue<T> extends ObxWidget {
-  final Widget Function(T? data) builder;
-  final Rx<T> data = Rx<T>();
-
-  RxValue(this.builder, {Key? key}) : super(key: key);
-
-  @override
-  Widget build() => builder(data.value);
-}

 name: get
 name: get
 description: Open screens/snackbars/dialogs without context, manage states and inject dependencies easily with GetX.
 description: Open screens/snackbars/dialogs without context, manage states and inject dependencies easily with GetX.
-version: 4.0.0-nullsafety.2
+version: 4.0.0
 homepage: https://github.com/jonataslaw/getx
 homepage: https://github.com/jonataslaw/getx
 
 
 environment:
 environment:

@@ -129,4 +129,36 @@ void main() {
     await Future.delayed(Duration(milliseconds: 100));
     await Future.delayed(Duration(milliseconds: 100));
     expect(3, timesCalled);
     expect(3, timesCalled);
   });
   });
+
+  test('Rx String with non null values', () async {
+    final reactiveString = Rx<String>("abc");
+    var currentString;
+    reactiveString.listen((newString) {
+      currentString = newString;
+    });
+
+    expect(reactiveString.endsWith("c"), true);
+
+    // we call 3
+    reactiveString("b");
+
+    await Future.delayed(Duration.zero);
+    expect(currentString, "b");
+  });
+
+  test('Rx String with null values', () async {
+    var reactiveString = Rx<String?>(null);
+    var currentString;
+
+    reactiveString.listen((newString) {
+      currentString = newString;
+    });
+
+    // we call 3
+    reactiveString("abc");
+
+    await Future.delayed(Duration.zero);
+    expect(reactiveString.endsWith("c"), true);
+    expect(currentString, "abc");
+  });
 }
 }