Add support for deferred components

README.md

@@ -210,6 +210,14 @@ flutter:
     - assets/flare/Penguin.flr
     - assets/rive/vehicles.riv
     - pictures/ocean_view.jpg
+
+  # Also include assets from deferred components
+  # https://docs.flutter.dev/perf/deferred-components
+  deferred-components:
+    - name: myDeferredComponent
+      assets:
+        - assets/images/another_image.jps
+        - assets/videos/a_large_video.mp4
 ```
 
 These configurations will generate **`assets.gen.dart`** under the **`lib/gen/`** directory by default.

packages/core/lib/generators/assets_generator.dart

@@ -34,7 +34,7 @@ class AssetsGenConfig {
       pubspecFile.parent.absolute.path,
       config.pubspec.packageName,
       config.pubspec.flutterGen,
-      config.pubspec.flutter.assets,
+      _buildAssetsList(config),
       config.pubspec.flutterGen.assets.exclude.map(Glob.new).toList(),
     );
   }
@@ -49,6 +49,18 @@ class AssetsGenConfig {
       flutterGen.assets.outputs.packageParameterEnabled ? _packageName : '';
 }
 
+/// Merge the deferred assets with the main assets.
+List<Object> _buildAssetsList(Config config) {
+  // We may have several deferred components, with a list of assets for each.
+  // So before spreading the list of deferred components, we need to spread
+  // the list of assets for each deferred component.
+  final deferredComponents = config.pubspec.flutter.deferredComponents ?? [];
+  return deferredComponents.fold<List<Object>>(
+    config.pubspec.flutter.assets,
+    (list, deferredComponent) => list + (deferredComponent.assets ?? []),
+  );
+}
+
 Future<String> generateAssets(
   AssetsGenConfig config,
   DartFormatter formatter,

packages/core/lib/settings/pubspec.dart

@@ -29,6 +29,7 @@ class Flutter {
   Flutter({
     required this.assets,
     required this.fonts,
+    required this.deferredComponents,
   });
 
   @JsonKey(name: 'assets', required: true)
@@ -37,6 +38,9 @@ class Flutter {
   @JsonKey(name: 'fonts', required: true)
   final List<FlutterFonts> fonts;
 
+  @JsonKey(name: 'deferred-components', required: false)
+  final List<FlutterDeferredComponents>? deferredComponents;
+
   factory Flutter.fromJson(Map json) => _$FlutterFromJson(json);
 }
 
@@ -243,3 +247,20 @@ class FlutterGenElementFontsOutputs extends FlutterGenElementOutputs {
   factory FlutterGenElementFontsOutputs.fromJson(Map json) =>
       _$FlutterGenElementFontsOutputsFromJson(json);
 }
+
+@JsonSerializable()
+class FlutterDeferredComponents {
+  const FlutterDeferredComponents({
+    required this.name,
+    required this.assets,
+  });
+
+  @JsonKey(name: 'name', required: true)
+  final String name;
+
+  @JsonKey(name: 'assets', required: false)
+  final List<Object>? assets;
+
+  factory FlutterDeferredComponents.fromJson(Map json) =>
+      _$FlutterDeferredComponentsFromJson(json);
+}

packages/core/test/assets_gen_test.dart

@@ -134,6 +134,16 @@ void main() {
       await expectedAssetsGen(pubspec, generated, fact);
     });
 
+    test('Assets with deferred components assets', () async {
+      const pubspec = 'test_resources/pubspec_assets_deferred_components.yaml';
+      const fact =
+          'test_resources/actual_data/assets_deferred_components.gen.dart';
+      const generated =
+          'test_resources/lib/gen/assets_deferred_components.gen.dart';
+
+      await expectedAssetsGen(pubspec, generated, fact);
+    });
+
     test('Assets with duplicate flavoring entries', () async {
       const pubspec =
           'test_resources/pubspec_assets_flavored_duplicate_entry.yaml';