Emmanuel Vaïsse evaisse

Google Way of Dart

Copyright :

There are countless Flutter coding conventions floating around. From the popular “Flutter Clean Architecture” to community-driven style guides, developers have been following external conventions for years. I was one of them.

For the past 5 years, I followed community best practices, enforced strict linting rules, and structured my Flutter apps according to popular Medium articles and YouTube tutorials. My code was “clean,” and my architecture was “proper.”

Development Stack with Flutter

Flutter app, with provider for dependency management.
Always run flutter analyze to fix all errors, when there is errors, just run dart fix --apply before trying to manipulate the code by yourself
Always ensure your code is fully tested, with flutter test() or widgetTest(), add be generous with goldenTest and screen captures also
Always prefer type-safe alternative to dynamic, late and other risky behaviors
Do not cast with as keyword, but always prefer pattern matching to safely cast and test types
Never use the dynamic keyword, nor late, but prefer Object? which is safer
Always use flutter theme extension to allow UI customization, for every group of UI widgets you build, add a theme extension and refer to hit using context to customize the widgets.

	import 'package:flutter/material.dart';
	import 'package:provider/provider.dart';

	class ServiceBuilder<T extends Service> {
	final T Function(BuildContext context) create;

	ServiceBuilder(this.create);

	Provider<T> asProvider(ValueNotifier<BuildContext> scope) =>
	Provider<T>(create: (_) => create(scope.value));

	import 'package:flutter/material.dart';
	import 'package:provider/provider.dart';

	/// Represents a city using a record, with its name (including flag emoji),
	/// population, and seaside status.
	/// Records provide automatic equality and hash code implementation.
	typedef City = ({String name, int population, bool isSeaside});

	/// Manages the selection of a city and provides available city data.
	///

	import 'package:flutter/material.dart';
	import 'package:provider/provider.dart';

	/// Data model for the counter, extending ChangeNotifier to notify listeners of changes.
	class CounterData extends ValueNotifier<int> {
	CounterData() : super(0);

	void increment() => value = value + 1;
	}

	/// Attention à TOUJOURS typer le retour des callback/builders
	/// que vous allez passer aux widgets/controllers.
	class Foo {
	Function()? onFoo;
	void Function()? onFoufou;
	Foo({ this.onFoo, this.onFoufou });
	}

	void main() {


	/// General demonstration about the annoying way to set to null a copy of another object
	///
	/// @see https://github.com/dart-lang/language/issues/877
	/// @see https://stackoverflow.com/questions/68009392/dart-custom-copywith-method-with-nullable-properties
	class Person {
	final String name;
	final String? nickName;

	Person({required this.name, this.nickName});

	import 'dart:convert';
	import 'dart:math';
	import 'dart:typed_data';

	import 'package:basic_utils/basic_utils.dart';
	import 'package:encrypt/encrypt.dart';
	// ignore: depend_on_referenced_packages
	import 'package:crypto/crypto.dart';
	import 'package:flutter/foundation.dart' as flutter;
	import 'package:pointycastle/export.dart';

	// Définition d'une classe scellée pour représenter un résultat
	// Sealed class : https://dart.dev/language/class-modifiers#sealed
	sealed class ASealedClass {}
	// cas 1
	class Success extends ASealedClass {}
	// cas 2
	class Failure extends ASealedClass {}

	/// sous la forme d'un enum
	enum AnEnum { success, error }

	void main() {

	dynamic myDynamicValue = null;

	myDynamicValue.length;

	Object? myTypedValue = myDynamicValue;

	myTypedValue.length; // that's helpful