Create presenting-streams-in-flutter.dart

Author: vandadnp

tipsandtricks/presenting-streams-in-flutter/presenting-streams-in-flutter.dart

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+// 🐦 Twitter                   https://twitter.com/vandadnp
+// 🔵 LinkedIn                  https://linkedin.com/in/vandadnp
+// 🎥 YouTube                   https://youtube.com/c/vandadnp
+// 💙 Free Flutter Course       https://linktr.ee/vandadnp
+// 📦 11+ Hours Bloc Course     https://youtu.be/Mn254cnduOY
+// 🔶 7+ Hours MobX Course      https://youtu.be/7Od55PBxYkI
+// 🦄 8+ Hours RxSwift Coursde  https://youtu.be/xBFWMYmm9ro
+// 🤝 Want to support my work?  https://buymeacoffee.com/vandad
+
+import 'package:flutter/material.dart';
+
+void main() {
+  runApp(
+    const App(),
+  );
+}
+
+class App extends StatelessWidget {
+  const App({
+    Key? key,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      theme: ThemeData.dark(),
+      debugShowCheckedModeBanner: false,
+      home: const HomePage(),
+    );
+  }
+}
+
+extension PresentAsyncSnapshot<E> on AsyncSnapshot<E> {
+  Widget present({
+    required BuildContext context,
+    Widget Function(BuildContext context)? onNone,
+    Widget Function(BuildContext context, E data)? onData,
+    Widget Function(BuildContext, Object error, StackTrace stackTrace)? onError,
+    Widget Function(BuildContext context)? onDoneWitNeitherDataNorError,
+    Widget Function(BuildContext context)? onWaiting,
+  }) {
+    switch (connectionState) {
+      case ConnectionState.none:
+        return onNone?.call(context) ?? const SizedBox.shrink();
+      case ConnectionState.waiting:
+        return onWaiting?.call(context) ?? const CircularProgressIndicator();
+      case ConnectionState.active:
+      case ConnectionState.done:
+        if (hasError) {
+          return onError?.call(context, error!, stackTrace!) ??
+              const SizedBox.shrink();
+        } else if (hasData) {
+          return onData?.call(context, data as E) ?? const SizedBox.shrink();
+        } else {
+          return onDoneWitNeitherDataNorError?.call(context) ??
+              const SizedBox.shrink();
+        }
+    }
+  }
+}
+
+Stream<String> getDateTime() => Stream.periodic(
+      const Duration(seconds: 1),
+      (_) => DateTime.now().toIso8601String(),
+    );
+
+extension PresentStream<E> on Stream<E> {
+  Widget present({
+    Widget Function(BuildContext context)? onNone,
+    Widget Function(BuildContext context, E data)? onData,
+    Widget Function(BuildContext, Object error, StackTrace stackTrace)? onError,
+    Widget Function(BuildContext context)? onDoneWitNeitherDataNorError,
+    Widget Function(BuildContext context)? onWaiting,
+  }) {
+    return StreamBuilder<E>(
+      stream: this,
+      builder: (context, snapshot) => snapshot.present(
+        context: context,
+        onNone: onNone,
+        onData: onData,
+        onError: onError,
+        onDoneWitNeitherDataNorError: onDoneWitNeitherDataNorError,
+        onWaiting: onWaiting,
+      ),
+    );
+  }
+}
+
+class HomePage extends StatelessWidget {
+  const HomePage({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: SafeArea(
+        child: getDateTime().present(
+          onData: (_, dateTime) => Text(dateTime),
+        ),
+      ),
+    );
+  }
+}