Features

🎯 Flutter Ready

fromJson factory constructor
toJson serialization method
Nested class generation
camelCase field names

🔒 Null Safety

Dart 2.12+ null safety support
Nullable types with ?
Required constructor parameters
Type-safe field access

⚙️ Equatable Support

Optional Equatable extension
Value equality comparison
props list generation
BLoC/Cubit compatible

Dart JSON Guide

Dart JSON Serialization

Dart classes can be manually serialized using fromJson/toJson methods or with code generation via json_serializable. Manual serialization is straightforward and requires no build step.

# pubspec.yaml (for Equatable support)
dependencies:
  equatable: ^2.0.5

// Usage example
final json = {'id': 1, 'name': 'Alice'};
final user = Root.fromJson(json);
final backToJson = user.toJson();

Parsing JSON in Flutter

import 'dart:convert';

// From HTTP response
final response = await http.get(Uri.parse('https://api.example.com/user'));
if (response.statusCode == 200) {
  final Map<String, dynamic> data = json.decode(response.body);
  final user = Root.fromJson(data);
  print(user.name);
}

Common Use Cases

REST APIs: Deserialize HTTP responses in Flutter apps
Local Storage: Encode/decode objects for SharedPreferences or Hive
BLoC Pattern: Equatable models for state management
Firebase: Map Firestore document snapshots to typed models
WebSockets: Parse real-time JSON message streams

FAQ

Q: Should I use manual serialization or json_serializable?

A: Manual serialization (fromJson/toJson) works well for simple projects. For larger codebases, json_serializable with build_runner generates boilerplate automatically and is less error-prone.

Q: What is Equatable used for?

A: Equatable overrides == and hashCode based on the props list, enabling value equality. This is particularly useful when using BLoC or Cubit for state management where state comparisons trigger rebuilds.

Using generated Dart models in Flutter

Hand-written fromJson and toJson methods are easy to read and have no build step, which makes them a good fit for small and medium Flutter apps. A few habits keep them correct as the API evolves.

Tips and common pitfalls

JSON numbers decode as int or double depending on the value, so cast with (json["price"] as num).toDouble() for fields that may be whole numbers.
Give nullable fields a ? type and handle missing keys; a missing key returns null from the map lookup.
Decode large responses in a background isolate with compute() so parsing does not drop frames.
Add a copyWith method when models are used in state management, so you can update one field without rebuilding the whole object.

JSON to Dart Class