Detailed explanation of 8 amazing usages in Darts

Dart is a modern programming language developed by Google. With its concise syntax and powerful functions, it has won a high reputation among developers, especially in the Flutter framework. This article will introduce 8 amazing uses in Dart, which are not only technically profound and inspiring, but also can quickly improve your Dart programming efficiency.

1. Advanced application of generic type alias

Type alias allows you to define more complex types with simple names, especially useful when dealing with large numbers of nested generics.

typedef ComplexList<T> = List<Map<T, T>>;

void main() {
  // Suitable for lists where specific key-value pair types need to be set  ComplexList<String> complexList = [
    {'key1': 'value1'},
    {'key2': 'value2'},
  ];
  
  // Operation of complex collections  ({'key3': 'value3'});
  print(complexList);
}

Generic type alias can better organize the code and enhance the readability of the code.

2. Advanced Stream processing skills

Using various operators and converters provided by Stream, you can better handle event streams and asynchronous data.

Stream<int> timedCounter(Duration interval, int maxCount) async* {
  int count = 0;
  while (count < maxCount) {
    await (interval);
    yield ++count;
  }
}

void main() async {
  // Listen to Stream and execute specific logic  await for (final count in timedCounter(Duration(seconds: 1), 5)) {
    print(count); 
  }
}

passasync*andyield, you can build a Stream that can transmit data sequences, providing powerful support for asynchronous programming.

3. Lightweight parallel computing of Isolate

Isolate can be transported in different execution threads and is a powerful tool for performing concurrent operations.

import 'dart:isolate';

Future<void> computeOnIsolate() async {
  final receivePort = ReceivePort();
  
  (_heavyComputation, );
  
  final message = await  as String;
  print(message);
}

void _heavyComputation(SendPort sendPort) {
  // Very heavy calculation  // Assume this is an operation that keeps the CPU full  ('Computation is completed');
}

void main() {
  computeOnIsolate();
}

Isolate allows you to perform time-consuming operations in your Flutter app without affecting your application's responsiveness.

4. Advanced tips for using enumeration

Enum types can not only represent a set of named constants, but their functionality can be greatly improved through extension methods.

enum ConnectionState {
  none,
  waiting,
  active,
  done,
}

extension ConnectionStateX on ConnectionState {
  bool get isTerminal => this == ;
}

void main() {
  final state = ;
  
  print('Is the connection terminal? ${}');
}

The extensibility of enumeration types provides an object-oriented pattern, which allows additional functionality to be added while ensuring type safety.

5. Use advanced const constructors

The const constructor allows the creation of immutable instances at compile time, which is conducive to performance optimization.

class ImmutableWidget {
  final int id;
  final String name;

  const ImmutableWidget({, });

  @override
  String toString() => 'ImmutableWidget(id: $id, name: $name)';
}

void main() {
  const widget1 = ImmutableWidget(id: 1, name: 'Widget 1');
  const widget2 = ImmutableWidget(id: 1, name: 'Widget 1');

  //The identifiers are the same, they are the same instance  print(identical(widget1, widget2)); // Output: true}

Insts created using the const constructor, since they are immutable, can be reused by the Dart VM in multiple places.

6. Metadata annotation and reflection

Althoughdart:mirrorsLibrary is not available in Flutter, but understanding the use of metadata can provide you with design inspiration.

import 'dart:mirrors'; // Note that it is not available on non-Web platforms
class Route {
  final String path;
  const Route();
}

@Route('/login')
class LoginPage {}

void main() {
  final mirror = reflectClass(LoginPage);
  for (final instanceMirror in ) {
    final annotation = ;
    if (annotation is Route) {
      print('LoginPageThe route is: ${}');
    }
  }
}

With annotations, you can add readable metadata to your code and get them at runtime through reflection, providing support for dynamic features, although it may be implemented in Flutter with other methods such as code generation.

7. Anonymous mixin

Creating anonymous mixins can reuse code without exposing mixins to global scope.

class Bird {
  void fly() {
    print('fly');
  }
}

class Swimmer {
  void swim() {
    print('swim');
  }
}

class Duck extends Bird with Swimmer {}

void main() {
  final duck = Duck();
  ();
  ();
}

Using anonymous mixins can mix the same functions in different classes without creating obvious class hierarchies, realizing code reuse.

8. Advanced asynchronous programming skills

In asynchronous programming, Dart provides powerful tools such as Future, Stream, async and await.

Future<String> fetchUserData() {
  // Assume this is a network request  return (Duration(seconds: 2), () => 'User Data');
}

Future<void> logInUser(String userId) async {
  print('Try to log in to the user...');
  try {
    final data = await fetchUserData();
    print('Login successfully: $data');
  } catch (e) {
    print('Login failed: $e');
  }
}

void main() {
  logInUser('123');
}

By usingasyncandawait, can write asynchronous operations that look like synchronous code, making asynchronous code more concise and easy to understand.

This is the end of this article about the stunning detailed explanation of the 8 Darts. For more relevant Dart usage content, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!