refactor: categories to first class objects (#1348)

Author: matiasleyba

flutter_news_example/api/lib/src/client/flutter_news_example_api_client.dart

@@ -155,18 +155,18 @@ class FlutterNewsExampleApiClient {
   /// Requests news feed metadata.
   ///
   /// Supported parameters:
-  /// * [category] - The desired news [Category].
+  /// * [categoryId] - The desired id of news category.
   /// * [limit] - The number of results to return.
   /// * [offset] - The (zero-based) offset of the first item
   /// in the collection to return.
   Future<FeedResponse> getFeed({
-    Category? category,
+    String? categoryId,
     int? limit,
     int? offset,
   }) async {
     final uri = Uri.parse('$_baseUrl/api/v1/feed').replace(
       queryParameters: <String, String>{
-        if (category != null) 'category': category.name,
+        if (categoryId != null) 'category': categoryId,
         if (limit != null) 'limit': '$limit',
         if (offset != null) 'offset': '$offset',
       },

flutter_news_example/api/lib/src/data/in_memory_news_data_source.dart

@@ -102,12 +102,12 @@ class InMemoryNewsDataSource implements NewsDataSource {
 
   @override
   Future<Feed> getFeed({
-    Category category = Category.top,
+    required String categoryId,
     int limit = 20,
     int offset = 0,
   }) async {
     final feed =
-        _newsFeedData[category] ?? const Feed(blocks: [], totalBlocks: 0);
+        _newsFeedData[categoryId] ?? const Feed(blocks: [], totalBlocks: 0);
     final totalBlocks = feed.totalBlocks;
     final normalizedOffset = math.min(offset, totalBlocks);
     final blocks = feed.blocks.sublist(normalizedOffset).take(limit).toList();

flutter_news_example/api/lib/src/data/news_data_source.dart

@@ -59,8 +59,7 @@ abstract class NewsDataSource {
     int offset = 0,
   });
 
-  /// Returns a news [Feed] for the provided [category].
-  /// By default [Category.top] is used.
+  /// Returns a news [Feed] for the provided [categoryId].
   ///
   /// In addition, the feed can be paginated by supplying
   /// [limit] and [offset].
@@ -69,7 +68,7 @@ abstract class NewsDataSource {
   /// * [offset] - The (zero-based) offset of the first item
   /// in the collection to return.
   Future<Feed> getFeed({
-    Category category = Category.top,
+    required String categoryId,
     int limit = 20,
     int offset = 0,
   });

flutter_news_example/api/lib/src/data/static_news_data.dart

@@ -1383,19 +1383,19 @@ List<NewsItem> get _newsItems {
   ];
 }
 
-final _newsFeedData = <Category, Feed>{
-  _topCategory: topNewsFeedBlocks.toFeed(),
-  _technologyCategory: technologyFeedBlocks.toFeed(),
-  _sportsCategory: sportsFeedBlocks.toFeed(),
-  _healthCategory: healthFeedBlocks.toFeed(),
-  _scienceCategory: scienceFeedBlocks.toFeed(),
+final _newsFeedData = <String, Feed>{
+  _topCategory.id: topNewsFeedBlocks.toFeed(),
+  _technologyCategory.id: technologyFeedBlocks.toFeed(),
+  _sportsCategory.id: sportsFeedBlocks.toFeed(),
+  _healthCategory.id: healthFeedBlocks.toFeed(),
+  _scienceCategory.id: scienceFeedBlocks.toFeed(),
 };
 
-const _topCategory = Category.top;
-const _sportsCategory = Category.sports;
-const _technologyCategory = Category.technology;
-const _healthCategory = Category.health;
-const _scienceCategory = Category.science;
+const _topCategory = Category(id: 'top', name: 'Top');
+const _sportsCategory = Category(id: 'sports', name: 'Sports');
+const _technologyCategory = Category(id: 'technology', name: 'Technology');
+const _healthCategory = Category(id: 'health', name: 'Health');
+const _scienceCategory = Category(id: 'science', name: 'Science');
 
 const _categories = [
   _topCategory,

flutter_news_example/api/lib/src/models/categories_response/categories_response.dart

@@ -7,7 +7,7 @@ part 'categories_response.g.dart';
 /// {@template categories_response}
 /// A news categories response object which contains available news categories.
 /// {@endtemplate}
-@JsonSerializable()
+@JsonSerializable(explicitToJson: true)
 class CategoriesResponse extends Equatable {
   /// {@macro categories_response}
   const CategoriesResponse({required this.categories});

flutter_news_example/api/lib/src/models/categories_response/categories_response.g.dart

@@ -1,30 +1,33 @@
-/// The supported news category types.
-enum Category {
-  /// News relating to business.
-  business,
-
-  /// News relating to entertainment.
-  entertainment,
-
-  /// Breaking news.
-  top,
-
-  /// News relating to health.
-  health,
-
-  /// News relating to science.
-  science,
-
-  /// News relating to sports.
-  sports,
-
-  /// News relating to technology.
-  technology;
-
-  /// The id of the category.
-  String get id => name;
-
-  /// Returns a [Category] for the [categoryName].
-  static Category fromString(String categoryName) =>
-      Category.values.firstWhere((category) => category.name == categoryName);
+import 'package:equatable/equatable.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'category.g.dart';
+
+/// {@template category}
+/// Represents a news category.
+/// {@endtemplate}
+@JsonSerializable()
+class Category extends Equatable {
+  /// {@macro category}
+  const Category({
+    required this.id,
+    required this.name,
+  });
+
+  /// Converts a `Map<String, dynamic>` into
+  /// a [Category] instance.
+  factory Category.fromJson(Map<String, dynamic> json) =>
+      _$CategoryFromJson(json);
+
+  /// Category id.
+  final String id;
+
+  /// Category name.
+  final String name;
+
+  /// Converts the current instance to a `Map<String, dynamic>`.
+  Map<String, dynamic> toJson() => _$CategoryToJson(this);
+
+  @override
+  List<Object?> get props => [id, name];
 }

flutter_news_example/api/packages/news_blocks/lib/src/block_action.g.dart

@@ -4,7 +4,7 @@ import 'package:test/test.dart';
 void main() {
   group('ArticleIntroductionBlock', () {
     test('can be (de)serialized', () {
-      const category = Category.technology;
+      const category = Category(id: 'technology', name: 'Technology');
       final block = ArticleIntroductionBlock(
         categoryId: category.id,
         author: 'author',

flutter_news_example/api/packages/news_blocks/lib/src/category.dart

@@ -7,10 +7,11 @@ void main() {
   group('BlockActionConverter', () {
     test('can (de)serialize BlockAction', () {
       final converter = BlockActionConverter();
+      const category = Category(id: 'sports', name: 'Sports');
 
       const actions = <BlockAction>[
         NavigateToArticleAction(articleId: 'articleId'),
-        NavigateToFeedCategoryAction(category: Category.top),
+        NavigateToFeedCategoryAction(category: category),
       ];
 
       for (final action in actions) {

flutter_news_example/api/packages/news_blocks/lib/src/category.g.dart

@@ -46,7 +46,9 @@ void main() {
       });
 
       test('returns NavigateToFeedCategoryAction', () {
-        final action = NavigateToFeedCategoryAction(category: Category.top);
+        const category = Category(id: 'sports', name: 'Sports');
+
+        final action = NavigateToFeedCategoryAction(category: category);
         expect(BlockAction.fromJson(action.toJson()), equals(action));
       });
 
@@ -91,7 +93,9 @@ void main() {
 
     group('NavigateToFeedCategoryAction', () {
       test('can be (de)serialized', () {
-        final action = NavigateToFeedCategoryAction(category: Category.top);
+        const category = Category(id: 'sports', name: 'Sports');
+
+        final action = NavigateToFeedCategoryAction(category: category);
         expect(
           NavigateToFeedCategoryAction.fromJson(action.toJson()),
           equals(action),

flutter_news_example/api/packages/news_blocks/test/src/article_introduction_block_test.dart

@@ -2,56 +2,21 @@ import 'package:news_blocks/news_blocks.dart';
 import 'package:test/test.dart';
 
 void main() {
-  group('Category', () {
-    group('fromString', () {
-      test('returns business', () {
-        expect(
-          Category.fromString('business'),
-          equals(Category.business),
-        );
-      });
-
-      test('returns business', () {
-        expect(
-          Category.fromString('entertainment'),
-          equals(Category.entertainment),
-        );
-      });
-
-      test('returns top', () {
-        expect(
-          Category.fromString('top'),
-          equals(Category.top),
-        );
-      });
-
-      test('returns health', () {
-        expect(
-          Category.fromString('health'),
-          equals(Category.health),
-        );
-      });
-
-      test('returns science', () {
-        expect(
-          Category.fromString('science'),
-          equals(Category.science),
-        );
-      });
-
-      test('returns sports', () {
-        expect(
-          Category.fromString('sports'),
-          equals(Category.sports),
-        );
-      });
+  group(Category, () {
+    test('can be (de)serialized', () {
+      const category = Category(id: 'sports', name: 'Sports');
+      expect(
+        Category.fromJson(const {'id': 'sports', 'name': 'Sports'}),
+        equals(category),
+      );
+    });
 
-      test('returns technology', () {
-        expect(
-          Category.fromString('technology'),
-          equals(Category.technology),
-        );
-      });
+    test('can be serialized', () {
+      const category = Category(id: 'sports', name: 'Sports');
+      expect(
+        category.toJson(),
+        equals(const {'id': 'sports', 'name': 'Sports'}),
+      );
     });
   });
 }