json-serializationlisted
Install: claude install-skill smicolon/ai-kit
# JSON Serialization in Flutter
Best practices for mapping API JSON payloads to Dart models safely.
## 1. Immutable Model Pattern (No Code-Gen)
Ideal for simple to medium entities without heavy dependencies:
```dart
class UserModel {
final String id;
final String email;
final String? displayName;
final DateTime createdAt;
const UserModel({
required this.id,
required this.email,
this.displayName,
required this.createdAt,
});
factory UserModel.fromJson(Map<String, dynamic> json) {
return UserModel(
id: json['id'] as String,
email: json['email'] as String,
displayName: json['display_name'] as String?,
createdAt: DateTime.parse(json['created_at'] as String),
);
}
Map<String, dynamic> toJson() {
return {
'id': id,
'email': email,
if (displayName != null) 'display_name': displayName,
'created_at': createdAt.toIso8601String(),
};
}
UserModel copyWith({
String? id,
String? email,
String? displayName,
DateTime? createdAt,
}) {
return UserModel(
id: id ?? this.id,
email: email ?? this.email,
displayName: displayName ?? this.displayName,
createdAt: createdAt ?? this.createdAt,
);
}
}
```
## 2. Safe Parsing Helper
Always guard against nulls or unexpected types from network responses:
```dart
int parseCount(dynamic value) {
if (value is int) return value;
if (value is String) return int.tryParse(value) ?? 0;
return 0;
}
``