Add support for Flutter deferred components

Author: Ian Maciel

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 +49,17 @@ class AssetsGenConfig {
       flutterGen.assets.outputs.packageParameterEnabled ? _packageName : '';
 }
 
+List<Object> _buildAssetsList(Config config) {
+  final List<Object> deferredAssets = [];
+  config.pubspec.flutter.deferredComponents?.forEach((deferredComponent) {
+    // Include all manipulated assets to the list of deferred assets.
+    deferredAssets.addAll(deferredComponent.assets ?? []);
+  });
+
+  // Merge the deferred assets with the main assets.
+  return [...config.pubspec.flutter.assets, ...deferredAssets];
+}
+
 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 +247,19 @@ class FlutterGenElementFontsOutputs extends FlutterGenElementOutputs {
   factory FlutterGenElementFontsOutputs.fromJson(Map json) =>
       _$FlutterGenElementFontsOutputsFromJson(json);
 }
+
+class FlutterDeferredComponents {
+  FlutterDeferredComponents({
+    required this.name,
+    required this.assets,
+  });
+
+  @JsonKey(name: 'name', required: true)
+  final String name;
+
+  @JsonKey(name: 'assets', required: false)
+  final List<Object>? assets;
+
+  factory FlutterDeferredComponents.fromJson(Map json) =>
+      _$FlutterDeferredComponentsFromJson(json);
+}