Merge pull request #41 from flutter-news-app-full-source-code/aa

Enhance serialization

Author: fulleni

README.md

@@ -1,6 +1,6 @@
 # 🛠️ core
 
-![coverage: percentage](https://img.shields.io/badge/coverage-99-green)
+![coverage: percentage](https://img.shields.io/badge/coverage-98-green)
 [![style: very good analysis](https://img.shields.io/badge/style-very_good_analysis-B22C89.svg)](https://pub.dev/packages/very_good_analysis)
 [![License: PolyForm Free Trial](https://img.shields.io/badge/License-PolyForm%20Free%20Trial-blue)](https://polyformproject.org/licenses/free-trial/1.0.0)
 

lib/src/models/core/feed_item.dart

@@ -73,6 +73,51 @@ abstract class FeedItem extends Equatable {
     }
   }
 
+  /// Static factory method to serialize a [FeedItem] instance to a JSON map.
+  ///
+  /// This factory uses the `type` field of the provided [item] to dispatch
+  /// to the correct concrete `toJson` method.
+  ///
+  /// Throws [FormatException] if the `type` field is missing or unknown.
+  static Map<String, dynamic> toJson(FeedItem item) {
+    switch (item.type) {
+      case 'headline':
+        final headlineItem = item as Headline;
+        return headlineItem.toJson();
+      case 'topic':
+        final topicItem = item as Topic;
+        return topicItem.toJson();
+      case 'source':
+        final sourceItem = item as Source;
+        return sourceItem.toJson();
+      case 'country':
+        final countryItem = item as Country;
+        return countryItem.toJson();
+      case 'callToAction':
+        final callToActionItem = item as CallToActionItem;
+        return callToActionItem.toJson();
+      case 'localAd':
+        final localAdItem = item as LocalAd;
+        return LocalAd.toJson(localAdItem);
+      case 'contentCollection':
+        // For ContentCollectionItem, we need to know the generic type T
+        // to call its toJson method correctly.
+        // This requires a runtime type check and casting.
+        if (item is ContentCollectionItem<Topic>) {
+          return item.toJson((topic) => topic.toJson());
+        } else if (item is ContentCollectionItem<Source>) {
+          return item.toJson((source) => source.toJson());
+        } else if (item is ContentCollectionItem<Country>) {
+          return item.toJson((country) => country.toJson());
+        }
+        throw FormatException(
+          'Unknown ContentCollectionItem generic type: ${item.runtimeType}',
+        );
+      default:
+        throw FormatException('Unknown FeedItem type for toJson: ${item.type}');
+    }
+  }
+
   /// The type of the feed item, used as a discriminator for deserialization.
   final String type;
 

lib/src/models/feed_decorators/local_ad.dart

@@ -39,6 +39,31 @@ abstract class LocalAd extends FeedItem {
     }
   }
 
+  /// Static factory method to serialize a [LocalAd] instance to a JSON map.
+  ///
+  /// This factory uses the `adType` field of the provided [item] to dispatch
+  /// to the correct concrete `toJson` method.
+  ///
+  /// Throws [FormatException] if the `adType` field is missing or unknown.
+  static Map<String, dynamic> toJson(LocalAd item) {
+    switch (item.adType) {
+      case 'native':
+        final nativeAdItem = item as LocalNativeAd;
+        return nativeAdItem.toJson();
+      case 'banner':
+        final bannerAdItem = item as LocalBannerAd;
+        return bannerAdItem.toJson();
+      case 'interstitial':
+        final interstitialAdItem = item as LocalInterstitialAd;
+        return interstitialAdItem.toJson();
+      case 'video':
+        final videoAdItem = item as LocalVideoAd;
+        return videoAdItem.toJson();
+      default:
+        throw FormatException('Unknown LocalAd type for toJson: ${item.adType}');
+    }
+  }
+
   /// The type of the ad (e.g., banner, native, interstitial, video).
   final String adType;
 

test/src/models/feed_decorators/local_ad_test.dart

@@ -73,13 +73,48 @@ void main() {
             isA<FormatException>().having(
               (e) => e.message,
               'message',
-              'Unknown LocalAds type: unknown_type',
+              'Unknown LocalAd type: unknown_type', // Corrected from LocalAds
             ),
           ),
         );
       });
     });
 
+    group('toJson dispatching', () {
+      test('serializes LocalNativeAd correctly via LocalAd.toJson', () {
+        final mockLocalNativeAd =
+            localAdsFixturesData.firstWhere((ad) => ad.adType == 'native')
+                as LocalNativeAd;
+        final json = mockLocalNativeAd.toJson();
+        expect(LocalAd.toJson(mockLocalNativeAd), equals(json));
+      });
+
+      test('serializes LocalBannerAd correctly via LocalAd.toJson', () {
+        final mockLocalBannerAd =
+            localAdsFixturesData.firstWhere((ad) => ad.adType == 'banner')
+                as LocalBannerAd;
+        final json = mockLocalBannerAd.toJson();
+        expect(LocalAd.toJson(mockLocalBannerAd), equals(json));
+      });
+
+      test('serializes LocalInterstitialAd correctly via LocalAd.toJson', () {
+        final mockLocalInterstitialAd =
+            localAdsFixturesData.firstWhere((ad) => ad.adType == 'interstitial')
+                as LocalInterstitialAd;
+        final json = mockLocalInterstitialAd.toJson();
+        expect(LocalAd.toJson(mockLocalInterstitialAd), equals(json));
+      });
+
+      test('serializes LocalVideoAd correctly via LocalAd.toJson', () {
+        final mockLocalVideoAd =
+            localAdsFixturesData.firstWhere((ad) => ad.adType == 'video')
+                as LocalVideoAd;
+        final json = mockLocalVideoAd.toJson();
+        expect(LocalAd.toJson(mockLocalVideoAd), equals(json));
+      });
+
+    });
+
     // Test props for a concrete LocalAd subclass (LocalNativeAd)
     // The test name is misleading as it tests a concrete instance's props.
     // The expectation is updated to reflect all properties of LocalNativeAd.