Generalize an isEnum helper, added to utils.dart

json_serializable/lib/src/type_helpers/enum_helper.dart

@@ -14,27 +14,28 @@ class EnumHelper extends TypeHelper {
   @override
   String serialize(
       DartType targetType, String expression, SerializeContext context) {
-    if (targetType is InterfaceType && targetType.element.isEnum) {
-      return commonNullPrefix(
-          context.nullable, expression, "$expression.toString().split('.')[1]");
+    if (!isEnum(targetType)) {
+      return null;
     }
 
-    return null;
+    return commonNullPrefix(
+        context.nullable, expression, "$expression.toString().split('.')[1]");
   }
 
   @override
   String deserialize(
       DartType targetType, String expression, DeserializeContext context) {
-    if (targetType is InterfaceType && targetType.element.isEnum) {
-      var wrappedExpression =
-          simpleExpression.hasMatch(expression) ? expression : '{$expression}';
-
-      return commonNullPrefix(
-          context.nullable,
-          expression,
-          '$targetType.values.singleWhere('
-          "(x) => x.toString() == '$targetType.\$$wrappedExpression')");
+    if (!isEnum(targetType)) {
+      return null;
     }
-    return null;
+
+    var wrappedExpression =
+        simpleExpression.hasMatch(expression) ? expression : '{$expression}';
+
+    return commonNullPrefix(
+        context.nullable,
+        expression,
+        '$targetType.values.singleWhere('
+        "(x) => x.toString() == '$targetType.\$$wrappedExpression')");
   }
 }

json_serializable/lib/src/utils.dart

@@ -4,13 +4,17 @@
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
 
 // ignore: implementation_imports
 import 'package:analyzer/src/dart/resolver/inheritance_manager.dart'
     show InheritanceManager;
 
 import 'package:source_gen/source_gen.dart';
 
+bool isEnum(DartType targetType) =>
+    targetType is InterfaceType && targetType.element.isEnum;
+
 /// Returns a quoted String literal for [value] that can be used in generated
 /// Dart code.
 String escapeDartString(String value) {

json_serializable/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_serializable
-version: 0.5.0
+version: 0.5.1-dev
 author: Dart Team <misc@dartlang.org>
 description: Generates utilities to aid in serializing to/from JSON.
 homepage: https://github.com/dart-lang/json_serializable

json_serializable/tool/build.dart

@@ -4,6 +4,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:io' show exitCode;
 
 import 'package:build/build.dart';
 import 'package:build_config/build_config.dart';
@@ -130,6 +131,6 @@ class _Replacement {
   }
 }
 
-main(List<String> args) {
-  run(args, builders);
+main(List<String> args) async {
+  exitCode = await run(args, builders);
 }