Dart data class example

main.dart

/*
 * Dart data class example
 * https://gist.github.com/PlugFox/6a6d73a7822001af7f8558df89dbc60d
 * https://dartpad.dev/6a6d73a7822001af7f8558df89dbc60d
 * Matiunin Mikhail <plugfox@gmail.com>, 16 May 2022
 */

import 'package:meta/meta.dart';

void main() =>
    print(RideNotificationState.received(id: 1, title: 'Title').toJson());

/// {@template ride_notification_state}
/// RideNotificationState
/// {@endtemplate}
@immutable
// ignore: prefer_mixin
abstract class RideNotificationState with Comparable<RideNotificationState> {
  /// {@macro ride_notification_state}
  RideNotificationState({
    required this.id,
    required this.title,
    this.description = '',
    DateTime? updated,
    DateTime? created,
  })  : updated = updated ?? DateTime.now(),
        created = created ?? updated ?? DateTime.now();

  /// {@macro received_ride_notification_state}
  factory RideNotificationState.received({
    required int id,
    required String title,
    String description,
    DateTime? updated,
    DateTime? created,
  }) = ReceivedRideNotificationState;

  /// {@macro removed_ride_notification_state}
  factory RideNotificationState.removed({
    required int id,
    required String title,
    String description,
    DateTime? updated,
    DateTime? created,
  }) = ReceivedRideNotificationState;

  /// Generate Class from Map<String, Object?>
  factory RideNotificationState.fromJson(Map<String, Object?> json) {
    switch (json['type']) {
      case 'received':
        return ReceivedRideNotificationState.fromJson(json);
      case 'removed':
        return RemovedRideNotificationState.fromJson(json);
      default:
        throw StateError('Unknown type: ${json['type'] ?? 'null'}');
    }
  }

  /// The unique identifier for this object.
  final int id;

  /// The title of this object.
  final String title;

  /// A short description of this object.
  final String description;

  /// The date this object was last updated.
  final DateTime updated;

  /// The date this object was created.
  final DateTime created;

  /// This is removed state
  bool get isRemoved => maybeMap<bool>(
        orElse: () => false,
        removed: (r) => true,
      );

  /// Get received state or null
  ReceivedRideNotificationState? get receivedOrNull =>
      maybeMap<ReceivedRideNotificationState?>(
        orElse: () => null,
        received: (state) => state,
      );

  /// Generate Map<String, Object?> from class
  Map<String, Object?> toJson() => <String, Object?>{
        'id': id,
        'title': title,
        'description': description,
        'updated': updated.toUtc().toIso8601String(),
        'created': created.toUtc().toIso8601String(),
      };

  /// Create a copy of this object with the given values.
  RideNotificationState copyWith({
    int? newId,
    String? newTitle,
    String? newDescription,
    DateTime? newUpdated,
    DateTime? newCreated,
  });

  /// Map object
  T map<T>({
    required T Function(ReceivedRideNotificationState state) received,
    required T Function(RemovedRideNotificationState state) removed,
  });

  /// Map object
  T maybeMap<T>({
    required T Function() orElse,
    T Function(ReceivedRideNotificationState state)? received,
    T Function(RemovedRideNotificationState state)? removed,
  }) =>
      map<T>(
        received: received ?? (_) => orElse(),
        removed: removed ?? (_) => orElse(),
      );

  @override
  int compareTo(RideNotificationState other) => id.compareTo(other.id);

  @override
  int get hashCode => id;

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is RideNotificationState &&
          runtimeType == other.runtimeType &&
          id == other.id;

  @override
  String toString() => 'RideNotificationState#$id';
} // RideNotificationState

/// {@template received_ride_notification_state}
/// ReceivedRideNotificationState
/// {@endtemplate}
@immutable
class ReceivedRideNotificationState extends RideNotificationState {
  /// {@macro received_ride_notification_state}
  ReceivedRideNotificationState({
    required super.id,
    required super.title,
    super.description = '',
    super.updated,
    super.created,
  });

  /// Generate Class from Map<String, Object?>
  factory ReceivedRideNotificationState.fromJson(Map<String, Object?> json) =>
      ReceivedRideNotificationState(
        id: (json['id'] as int?)!,
        title: (json['title'] as String?)!,
        description: (json['description'] as String?)!,
        updated: DateTime.parse((json['updated'] as String?)!).toLocal(),
        created: DateTime.parse((json['created'] as String?)!).toLocal(),
      );

  @override
  Map<String, Object?> toJson() => <String, Object?>{
        'type': 'received_ride_notification_state',
        ...super.toJson(),
      };

  @override
  ReceivedRideNotificationState copyWith({
    int? newId,
    String? newTitle,
    String? newDescription,
    DateTime? newUpdated,
    DateTime? newCreated,
  }) =>
      ReceivedRideNotificationState(
        id: newId ?? id,
        title: newTitle ?? title,
        description: newDescription ?? description,
        updated: newUpdated ?? DateTime.now(),
        created: newCreated ?? created,
      );

  @override
  T map<T>({
    required T Function(ReceivedRideNotificationState state) received,
    required T Function(RemovedRideNotificationState state) removed,
  }) =>
      received(this);

  @override
  String toString() => 'ReceivedRideNotificationState#$id';
} // ReceivedRideNotificationState

/// {@template removed_ride_notification_state}
/// RemovedRideNotificationState
/// {@endtemplate}
@immutable
class RemovedRideNotificationState extends RideNotificationState {
  /// {@macro removed_ride_notification_state}
  RemovedRideNotificationState({
    required super.id,
    required super.title,
    super.description = '',
    super.updated,
    super.created,
  });

  /// Generate Class from Map<String, Object?>
  factory RemovedRideNotificationState.fromJson(Map<String, Object?> json) =>
      RemovedRideNotificationState(
        id: (json['id'] as int?)!,
        title: (json['title'] as String?)!,
        description: (json['description'] as String?)!,
        updated: DateTime.parse((json['updated'] as String?)!).toLocal(),
        created: DateTime.parse((json['created'] as String?)!).toLocal(),
      );

  @override
  Map<String, Object?> toJson() => <String, Object?>{
        'type': 'removed_ride_notification_state',
        ...super.toJson(),
      };

  @override
  RemovedRideNotificationState copyWith({
    int? newId,
    String? newTitle,
    String? newDescription,
    DateTime? newUpdated,
    DateTime? newCreated,
  }) =>
      RemovedRideNotificationState(
        id: newId ?? id,
        title: newTitle ?? title,
        description: newDescription ?? description,
        updated: newUpdated ?? DateTime.now(),
        created: newCreated ?? created,
      );

  @override
  T map<T>({
    required T Function(ReceivedRideNotificationState state) received,
    required T Function(RemovedRideNotificationState state) removed,
  }) =>
      removed(this);

  @override
  String toString() => 'RemovedRideNotificationState#$id';
} // RemovedRideNotificationState