✨ add option to override build_extension (#562)

chopper_generator/lib/src/builder_factory.dart

@@ -1,23 +1,61 @@
 import 'package:build/build.dart';
 import 'package:chopper/chopper.dart' show ChopperApi;
 import 'package:source_gen/source_gen.dart';
+import 'package:yaml/yaml.dart';
 
 import 'generator.dart';
 
 /// Creates a [PartBuilder] used to generate code for [ChopperApi] annotated
 /// classes. The [options] are provided by Dart's build system and read from the
 /// `build.yaml` file.
-Builder chopperGeneratorFactory(BuilderOptions options) => PartBuilder(
+Builder chopperGeneratorFactory(BuilderOptions options) {
+  final String buildExtension = _getBuildExtension(options);
+
+  return PartBuilder(
+    [const ChopperGenerator()],
+    buildExtension,
+    header: options.config['header'],
+    formatOutput: PartBuilder(
       [const ChopperGenerator()],
-      '.chopper.dart',
-      header: options.config['header'],
-      formatOutput:
-          PartBuilder([const ChopperGenerator()], '.chopper.dart').formatOutput,
-      options: !options.config.containsKey('build_extensions')
-          ? options.overrideWith(
-              BuilderOptions({
-                'build_extensions': {'.dart': '.chopper.dart'},
-              }),
-            )
-          : options,
-    );
+      buildExtension,
+    ).formatOutput,
+    options: !options.config.containsKey('build_extensions')
+        ? options.overrideWith(
+            BuilderOptions({
+              'build_extensions': {
+                '.dart': [buildExtension]
+              },
+            }),
+          )
+        : options,
+  );
+}
+
+/// Returns the build extension for the generated file.
+///
+/// If the `build.yaml` file contains a `build_extensions` key, it will be used
+/// to determine the extension. Otherwise, the default extension `.chopper.dart`
+/// will be used.
+///
+/// Example `build.yaml`:
+///
+/// ```yaml
+/// targets:
+///   $default:
+///     builders:
+///       chopper_generator:
+///         options:
+///           build_extensions: {".dart": [".chopper.g.dart"]}
+/// ```
+String _getBuildExtension(BuilderOptions options) {
+  if (options.config.containsKey('build_extensions')) {
+    final YamlMap buildExtensions = options.config['build_extensions'];
+    if (buildExtensions.containsKey('.dart')) {
+      final YamlList dartBuildExtensions = buildExtensions['.dart'];
+      if (dartBuildExtensions.isNotEmpty) {
+        return dartBuildExtensions.first;
+      }
+    }
+  }
+  return '.chopper.dart';
+}

chopper_generator/pubspec.yaml

@@ -17,6 +17,7 @@ dependencies:
   logging: ^1.2.0
   meta: ^1.9.1
   source_gen: ^1.4.0
+  yaml: ^3.1.2
 
 dev_dependencies:
   build_runner: ^2.4.6

faq.md

@@ -347,6 +347,22 @@ It goes without saying that running the code generation is a pre-requisite at th
 flutter pub run build_runner build
 ```
 
+##### Changing the default extension of the generated files
+
+If you want to change the default extension of the generated files from `.chopper.dart` to
+something else, you can do so by adding the following to your `build.yaml` file:
+
+```yaml
+targets:
+  $default:
+    builders:
+      chopper_generator:
+        options:
+          # This assumes you want the files to end with `.chopper.g.dart`
+          # instead of the default `.chopper.dart`.
+          build_extensions: { ".dart": [ ".chopper.g.dart" ] }
+```
+
 #### Configure a WorkerPool and run the example
 
 ```dart