Dart in 2024: 20 Features You Need to Know With Code Examples and Scenarios

Dart continues to grow in 2024, introducing a suite of powerful features and improvements to enhance developer productivity, improve performance, and streamline coding practices. In this article, we'll explore 20 essential updates in Dart 2024, complete with code examples and scenarios to demonstrate their practical impact.

1. Type Inference Refinements

Scenario: Simplifying asynchronous code with better type inference.

Code Example:

Future<int> fetchData() async => 42;

void main() async {
  var result = await fetchData();
  print(result); // Inferred as int
}

The await expression now benefits from improved type inference, reducing the need for explicit type annotations.

2. Microsecond Precision for DateTime on Web

Scenario: Building cross-platform apps requiring consistent date handling.

Code Example:

void main() {
  var now = DateTime.now();
  print(now.microsecondsSinceEpoch); // Accurate to microseconds on web and native.
}

Consistency between web and native platforms enhances reliability in time-sensitive applications.

3. Sound Null Safety Everywhere

Scenario: Migrating legacy projects with unsound null safety.

Code Example:

void greet(String? name) {
  print('Hello, ${name ?? "guest"}!');
}

void main() {
  greet(null); // No more unsound null safety options.
}

Sound null safety is now the only supported mode, ensuring safer and more predictable code.

4. Enhanced JavaScript Interop

Scenario: Integrating Dart with modern JavaScript modules.

Code Example:

import 'dart:js_interop';

void main() {
  final jsObject = JSObject();
  print(jsObject.isTruthy); // Uses improved JSInterop methods.
}

Developers can work more seamlessly with JavaScript values using dart:js_interop.

5. SecurityContext Improvements

Scenario: Securing HTTPS connections in server-side Dart apps.

Code Example:

import 'dart:io';

void main() {
  var context = SecurityContext();
  // Improved security configurations.
}

The SecurityContext class is now final, enhancing reliability.

6. dart2wasm Enhancements for WebAssembly

Scenario: Optimizing Dart apps for Wasm-based deployments.

Code Example:

dart compile wasm main.dart

The updated WebAssembly compiler simplifies configuration with clearer options.

7. Updated dart2js Behavior

Scenario: Minified production builds with improved debugging.

Code Example:

dart compile js -m

Minified builds retain original memberName in noSuchMethod, aiding error diagnostics.

8. New Annotations for Code Metadata

Scenario: Annotating APIs for better tooling support.

Code Example:

@Deprecated('Use newMethod instead')
void oldMethod() {}

void newMethod() {}

Annotations now have extended support for IDE tooling and compiler warnings.

9. Performance Improvements in Flutter

Scenario: Faster UI rendering for mobile apps.

Code Example:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: Scaffold(body: Text('Hello Flutter!')));
  }
}

Dart 2024 underpins Flutter's faster rendering engine, reducing latency in animations.

10. Finalized Constant Enhancements

Scenario: Simplifying immutable object declarations.

Code Example:

const list = [1, 2, 3]; // Optimized constant handling.

Improved support for constants ensures compile-time reliability.

11. Faster Compilation Times

Scenario: Iterating faster during development.

Dart SDK updates have reduced incremental compilation times, though no explicit code changes are needed to leverage this.

12. New Default Linter Rules

Scenario: Enforcing code quality in team projects.

Code Example:

linter:
  rules:
    - always_specify_types

New linter defaults help maintain consistent codebases across teams.

13. Async Enhancements

Scenario: Handling multiple futures more efficiently.

Code Example:

Future<void> main() async {
  await Future.wait([fetchData(), fetchData()]);
}

Updated async handling optimizes performance for concurrent operations.

14. Expanded Pattern Matching

Scenario: Simplifying conditional logic.

Code Example:

void main() {
  switch (42) {
    case var x if x.isEven:
      print('Even number');
  }
}

Enhanced pattern matching enables more expressive conditions.

15. Native Array Support

Scenario: Interfacing with C-style arrays in FFI.

Code Example:

import 'dart:ffi';

final array = calloc<Int32>(10);

Native array support improves performance in FFI integrations.

16. Better Error Messages

Scenario: Debugging large projects.

Error messages now include more context, helping diagnose issues faster.

17. package:ffi Updates

Scenario: Calling native libraries with fewer steps.

Code Example:

final dylib = DynamicLibrary.open('libnative.so');

FFI enhancements simplify native function calls.

18. Expanded dart:core Utilities

Scenario: Using new utilities for collections.

Code Example:

final map = {'key': 'value'};
print(map.entries); // Better utilities for iteration.

19. Streamlined Dependency Injection

Scenario: Building modular architectures.

Dependency injection frameworks benefit from language updates, though examples may vary by package.

20. Experimental Features Toggle

Scenario: Trying out the latest language experiments.

Code Example:

dart --enable-experiment=feature

You're absolutely right—sealed classes and final classes are pivotal features introduced in Dart 3. Let's include them with examples and practical development scenarios to showcase their importance in Dart 2024. I'll add them to the article as follows:

21. Sealed Classes

Scenario: Modeling restricted hierarchies for state management in Flutter apps.

Sealed classes allow you to define a fixed set of subclasses, ensuring better control and predictability over inheritance hierarchies.

Code Example:

sealed class Shape {}

class Circle extends Shape {
  final double radius;
  Circle(this.radius);
}

class Square extends Shape {
  final double side;
  Square(this.side);
}

void printArea(Shape shape) {
  switch (shape) {
    case Circle c:
      print('Circle area: ${3.14 * c.radius * c.radius}');
    case Square s:
      print('Square area: ${s.side * s.side}');
  }
}

void main() {
  var circle = Circle(10);
  var square = Square(5);
  printArea(circle);
  printArea(square);
}

Sealed classes are particularly useful for state classes in Flutter’s state management or modeling domains with limited types, such as payment methods or form states.

22. Final Classes

Scenario: Preventing unintended inheritance for secure and predictable APIs.

Final classes ensure that a class cannot be extended, providing clarity and security in library design.

Code Example:

final class Configuration {
  final String apiKey;
  final String baseUrl;

  Configuration(this.apiKey, this.baseUrl);
}

void main() {
  final config = Configuration('abc123', 'https://api.example.com');
  print(config.baseUrl);
}

In scenarios where a class is designed to be used as-is—like configuration objects or utility classes—marking it as final prevents misuse or unintended extension.

These two features—sealed classes and final classes—address common pain points in object-oriented programming by improving type safety and reducing unintended usage of classes in Dart projects. Their inclusion makes Dart more robust and developer-friendly.

Conclusion

Dart's 2024 updates offer a wide range of improvements for developers, from performance boosts to new language features and libraries. Whether you're building Flutter apps, server-side solutions, or web applications, these features make Dart an even more powerful tool. Try out these features today and take your development experience to the next level!

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