Use .map instead of new Map.fromIterables in a couple of places

json_serializable/CHANGELOG.md

@@ -1,5 +1,8 @@
 ## 0.5.4
 
+* Use `Map.map` for more map conversions. Simplifies generated code and fixes
+  a subtle issue when the `Map` key type is `dynamic` or `Object`.
+
 * Added `any_map` to configuration. Allows `fromJson` code to
   support dynamic `Map` instances that are not explicitly
   `Map<String, dynaimc>`.

json_serializable/lib/src/type_helpers/map_helper.dart

@@ -44,11 +44,10 @@ class MapHelper extends TypeHelper {
       return '$method<$keyType, $valueType>($expression, ($_closureArg) => $subFieldValue)';
     }
 
-    var result = 'new Map<String, dynamic>.fromIterables('
-        '$expression.keys,'
-        '$expression.values.map(($_closureArg) => $subFieldValue))';
+    final optionalQuestion = context.nullable ? '?' : '';
 
-    return commonNullPrefix(context.nullable, expression, result);
+    return '$expression$optionalQuestion'
+        '.map((k, $_closureArg) => new MapEntry(k, $subFieldValue))';
   }
 
   @override
@@ -58,22 +57,19 @@ class MapHelper extends TypeHelper {
       return null;
     }
 
-    // Just pass through if
-    //    key:   dynamic, Object, String
-    //    value: dynamic, Object
     var typeArgs = typeArgumentsOf(targetType, coreMapTypeChecker);
     assert(typeArgs.length == 2);
     var keyArg = typeArgs.first;
     var valueArg = typeArgs.last;
 
     _checkSafeKeyType(expression, keyArg);
 
-    var valueArgIsAny = valueArg.isDynamic || valueArg.isObject;
+    final valueArgIsAny = _isObjectOrDynamic(valueArg);
     var isAnyMap = context is TypeHelperContext && context.anyMap;
 
     if (valueArgIsAny) {
       if (isAnyMap) {
-        if (keyArg.isObject || keyArg.isDynamic) {
+        if (_isObjectOrDynamic(keyArg)) {
           return '$expression as Map';
         }
       } else {
@@ -93,28 +89,30 @@ class MapHelper extends TypeHelper {
     // In this case, we're going to create a new Map with matching reified
     // types.
 
-    var itemSubVal = context.deserialize(valueArg, _closureArg);
+    final itemSubVal = context.deserialize(valueArg, _closureArg);
 
-    var keyIterable = isAnyMap
-        ? '($expression as Map).keys.cast<String>()'
-        : '($expression as Map<String, dynamic>).keys';
+    final optionalQuestion = context.nullable ? '?' : '';
 
-    var result = 'new Map<String, $valueArg>.fromIterables($keyIterable,'
-        '($expression as Map).values.map(($_closureArg) => $itemSubVal))';
+    final mapCast = isAnyMap ? 'as Map' : 'as Map<String, dynamic>';
 
-    return commonNullPrefix(context.nullable, expression, result);
+    final keyUsage =
+        (isAnyMap && !_isObjectOrDynamic(keyArg)) ? 'k as String' : 'k';
+
+    return '($expression $mapCast)$optionalQuestion'
+        '.map((k, $_closureArg) => new MapEntry($keyUsage, $itemSubVal))';
   }
+}
 
-  void _checkSafeKeyType(String expression, DartType keyArg) {
-    // We're not going to handle converting key types at the moment
-    // So the only safe types for key are dynamic/Object/String
-    var safeKey = keyArg.isDynamic ||
-        keyArg.isObject ||
-        coreStringTypeChecker.isExactlyType(keyArg);
+bool _isObjectOrDynamic(DartType type) => type.isObject || type.isDynamic;
 
-    if (!safeKey) {
-      throw new UnsupportedTypeError(keyArg, expression,
-          'The type of the Map key must be `String`, `Object` or `dynamic`.');
-    }
+void _checkSafeKeyType(String expression, DartType keyArg) {
+  // We're not going to handle converting key types at the moment
+  // So the only safe types for key are dynamic/Object/String
+  var safeKey =
+      _isObjectOrDynamic(keyArg) || coreStringTypeChecker.isExactlyType(keyArg);
+
+  if (!safeKey) {
+    throw new UnsupportedTypeError(keyArg, expression,
+        'The type of the Map key must be `String`, `Object` or `dynamic`.');
   }
 }

json_serializable/test/kitchen_sink_test.dart

@@ -58,7 +58,7 @@ typedef KitchenSink KitchenSinkCtor(
 
 void _nonNullableTests(KitchenSinkCtor ctor, KitchenSink fromJson(Map json)) {
   test('with null values fails serialization', () {
-    expect(() => (ctor()..stringDateTimeMap = null).toJson(),
+    expect(() => (ctor()..objectDateTimeMap = null).toJson(),
         throwsNoSuchMethodError);
   });
 
@@ -92,7 +92,7 @@ void _nullableTests(KitchenSinkCtor ctor, KitchenSink fromJson(Map json)) {
     var now = new DateTime.now();
     var item = ctor(dateTimeIterable: <DateTime>[now])
       ..dateTimeList = <DateTime>[now, null]
-      ..stringDateTimeMap = <String, DateTime>{'value': now, 'null': null};
+      ..objectDateTimeMap = <Object, DateTime>{'value': now, 'null': null};
 
     roundTripItem(item);
   });
@@ -136,7 +136,7 @@ void _sharedTests(KitchenSinkCtor ctor, KitchenSink fromJson(Map json)) {
     var now = new DateTime.now();
     var item = ctor(dateTimeIterable: <DateTime>[now])
       ..dateTimeList = <DateTime>[now, now]
-      ..stringDateTimeMap = <String, DateTime>{'value': now};
+      ..objectDateTimeMap = <Object, DateTime>{'value': now};
 
     roundTripSink(item);
   });
@@ -216,8 +216,8 @@ final _validValues = const {
   'dateTimeList': const [],
   'map': const <String, dynamic>{},
   'stringStringMap': const {},
-  'stringIntMap': const {},
-  'stringDateTimeMap': const <String, dynamic>{},
+  'dynamicIntMap': const {},
+  'objectDateTimeMap': const <String, dynamic>{},
   'crazyComplex': const [],
   toJsonMapVarName: const {},
   toJsonMapHelperName: null,
@@ -240,8 +240,8 @@ final _invalidValues = const {
   'dateTimeList': const [true],
   'map': true,
   'stringStringMap': const {'key': 42},
-  'stringIntMap': const {'key': 'value'},
-  'stringDateTimeMap': const {'key': 42},
+  'dynamicIntMap': const {'key': 'value'},
+  'objectDateTimeMap': const {'key': 42},
   'crazyComplex': const [true],
   toJsonMapVarName: const {'key': 42},
   toJsonMapHelperName: 42,

json_serializable/test/test_files/json_test_example.g.dart

@@ -24,11 +24,10 @@ Person _$PersonFromJson(Map<String, dynamic> json) => new Person(
   ..order = json['order'] == null
       ? null
       : new Order.fromJson(json['order'] as Map<String, dynamic>)
-  ..houseMap = json['houseMap'] == null
-      ? null
-      : new Map<String, House>.fromIterables(
-          (json['houseMap'] as Map<String, dynamic>).keys,
-          (json['houseMap'] as Map).values.map((e) => e == null
+  ..houseMap = (json['houseMap'] as Map<String, dynamic>)?.map((k, e) =>
+      new MapEntry(
+          k,
+          e == null
               ? null
               : House.values.singleWhere((x) => x.toString() == 'House.$e')));
 
@@ -47,12 +46,8 @@ abstract class _$PersonSerializerMixin {
         'dateOfBirth': dateOfBirth?.toIso8601String(),
         r'$house': house == null ? null : house.toString().split('.')[1],
         'order': order,
-        'houseMap': houseMap == null
-            ? null
-            : new Map<String, dynamic>.fromIterables(
-                houseMap.keys,
-                houseMap.values
-                    .map((e) => e == null ? null : e.toString().split('.')[1]))
+        'houseMap': houseMap?.map((k, e) =>
+            new MapEntry(k, e == null ? null : e.toString().split('.')[1]))
       };
 }
 
@@ -66,12 +61,8 @@ Order _$OrderFromJson(Map<String, dynamic> json) => new Order(
   ..platform = json['platform'] == null
       ? null
       : new Platform.fromJson(json['platform'] as String)
-  ..altPlatforms = json['altPlatforms'] == null
-      ? null
-      : new Map<String, Platform>.fromIterables(
-          (json['altPlatforms'] as Map<String, dynamic>).keys,
-          (json['altPlatforms'] as Map).values.map(
-              (e) => e == null ? null : new Platform.fromJson(e as String)));
+  ..altPlatforms = (json['altPlatforms'] as Map<String, dynamic>)?.map((k, e) =>
+      new MapEntry(k, e == null ? null : new Platform.fromJson(e as String)));
 
 abstract class _$OrderSerializerMixin {
   int get count;

json_serializable/test/test_files/json_test_example.non_nullable.g.dart

@@ -17,10 +17,9 @@ Person _$PersonFromJson(Map<String, dynamic> json) => new Person(
     middleName: json['middleName'] as String,
     dateOfBirth: DateTime.parse(json['dateOfBirth'] as String))
   ..order = new Order.fromJson(json['order'] as Map<String, dynamic>)
-  ..houseMap = new Map<String, House>.fromIterables(
-      (json['houseMap'] as Map<String, dynamic>).keys,
-      (json['houseMap'] as Map).values.map(
-          (e) => House.values.singleWhere((x) => x.toString() == 'House.$e')));
+  ..houseMap = (json['houseMap'] as Map<String, dynamic>).map((k, e) =>
+      new MapEntry(
+          k, House.values.singleWhere((x) => x.toString() == 'House.$e')));
 
 abstract class _$PersonSerializerMixin {
   String get firstName;
@@ -37,8 +36,8 @@ abstract class _$PersonSerializerMixin {
         'dateOfBirth': dateOfBirth.toIso8601String(),
         r'$house': house.toString().split('.')[1],
         'order': order,
-        'houseMap': new Map<String, dynamic>.fromIterables(houseMap.keys,
-            houseMap.values.map((e) => e.toString().split('.')[1]))
+        'houseMap':
+            houseMap.map((k, e) => new MapEntry(k, e.toString().split('.')[1]))
       };
 }
 
@@ -50,11 +49,8 @@ Order _$OrderFromJson(Map<String, dynamic> json) => new Order(
   ..count = json['count'] as int
   ..isRushed = json['isRushed'] as bool
   ..platform = new Platform.fromJson(json['platform'] as String)
-  ..altPlatforms = new Map<String, Platform>.fromIterables(
-      (json['altPlatforms'] as Map<String, dynamic>).keys,
-      (json['altPlatforms'] as Map)
-          .values
-          .map((e) => new Platform.fromJson(e as String)));
+  ..altPlatforms = (json['altPlatforms'] as Map<String, dynamic>)
+      .map((k, e) => new MapEntry(k, new Platform.fromJson(e as String)));
 
 abstract class _$OrderSerializerMixin {
   int get count;

json_serializable/test/test_files/json_test_example.non_nullable.wrapped.g.dart

@@ -17,10 +17,9 @@ Person _$PersonFromJson(Map<String, dynamic> json) => new Person(
     middleName: json['middleName'] as String,
     dateOfBirth: DateTime.parse(json['dateOfBirth'] as String))
   ..order = new Order.fromJson(json['order'] as Map<String, dynamic>)
-  ..houseMap = new Map<String, House>.fromIterables(
-      (json['houseMap'] as Map<String, dynamic>).keys,
-      (json['houseMap'] as Map).values.map(
-          (e) => House.values.singleWhere((x) => x.toString() == 'House.$e')));
+  ..houseMap = (json['houseMap'] as Map<String, dynamic>).map((k, e) =>
+      new MapEntry(
+          k, House.values.singleWhere((x) => x.toString() == 'House.$e')));
 
 abstract class _$PersonSerializerMixin {
   String get firstName;
@@ -81,11 +80,8 @@ Order _$OrderFromJson(Map<String, dynamic> json) => new Order(
   ..count = json['count'] as int
   ..isRushed = json['isRushed'] as bool
   ..platform = new Platform.fromJson(json['platform'] as String)
-  ..altPlatforms = new Map<String, Platform>.fromIterables(
-      (json['altPlatforms'] as Map<String, dynamic>).keys,
-      (json['altPlatforms'] as Map)
-          .values
-          .map((e) => new Platform.fromJson(e as String)));
+  ..altPlatforms = (json['altPlatforms'] as Map<String, dynamic>)
+      .map((k, e) => new MapEntry(k, new Platform.fromJson(e as String)));
 
 abstract class _$OrderSerializerMixin {
   int get count;

json_serializable/test/test_files/json_test_example.wrapped.g.dart

@@ -24,11 +24,10 @@ Person _$PersonFromJson(Map<String, dynamic> json) => new Person(
   ..order = json['order'] == null
       ? null
       : new Order.fromJson(json['order'] as Map<String, dynamic>)
-  ..houseMap = json['houseMap'] == null
-      ? null
-      : new Map<String, House>.fromIterables(
-          (json['houseMap'] as Map<String, dynamic>).keys,
-          (json['houseMap'] as Map).values.map((e) => e == null
+  ..houseMap = (json['houseMap'] as Map<String, dynamic>)?.map((k, e) =>
+      new MapEntry(
+          k,
+          e == null
               ? null
               : House.values.singleWhere((x) => x.toString() == 'House.$e')));
 
@@ -93,12 +92,8 @@ Order _$OrderFromJson(Map<String, dynamic> json) => new Order(
   ..platform = json['platform'] == null
       ? null
       : new Platform.fromJson(json['platform'] as String)
-  ..altPlatforms = json['altPlatforms'] == null
-      ? null
-      : new Map<String, Platform>.fromIterables(
-          (json['altPlatforms'] as Map<String, dynamic>).keys,
-          (json['altPlatforms'] as Map).values.map(
-              (e) => e == null ? null : new Platform.fromJson(e as String)));
+  ..altPlatforms = (json['altPlatforms'] as Map<String, dynamic>)?.map((k, e) =>
+      new MapEntry(k, e == null ? null : new Platform.fromJson(e as String)));
 
 abstract class _$OrderSerializerMixin {
   int get count;

json_serializable/test/test_files/kitchen_sink.dart

@@ -93,8 +93,8 @@ class KitchenSink extends Object
 
   Map map = _defaultMap();
   Map<String, String> stringStringMap = _defaultMap();
-  Map<String, int> stringIntMap = _defaultMap();
-  Map<String, DateTime> stringDateTimeMap = _defaultMap();
+  Map<dynamic, int> dynamicIntMap = _defaultMap();
+  Map<Object, DateTime> objectDateTimeMap = _defaultMap();
 
   @JsonKey(includeIfNull: false)
   List<Map<String, Map<String, List<List<DateTime>>>>> crazyComplex =

json_serializable/test/test_files/kitchen_sink.g.dart

@@ -32,23 +32,16 @@ KitchenSink _$KitchenSinkFromJson(Map json) => new KitchenSink(
   ..stringStringMap = json['stringStringMap'] == null
       ? null
       : new Map<String, String>.from(json['stringStringMap'] as Map)
-  ..stringIntMap = json['stringIntMap'] == null
+  ..dynamicIntMap = json['dynamicIntMap'] == null
       ? null
-      : new Map<String, int>.from(json['stringIntMap'] as Map)
-  ..stringDateTimeMap = json['stringDateTimeMap'] == null
-      ? null
-      : new Map<String, DateTime>.fromIterables(
-          (json['stringDateTimeMap'] as Map).keys.cast<String>(),
-          (json['stringDateTimeMap'] as Map)
-              .values
-              .map((e) => e == null ? null : DateTime.parse(e as String)))
+      : new Map<String, int>.from(json['dynamicIntMap'] as Map)
+  ..objectDateTimeMap = (json['objectDateTimeMap'] as Map)?.map(
+      (k, e) => new MapEntry(k, e == null ? null : DateTime.parse(e as String)))
   ..crazyComplex = (json['crazyComplex'] as List)
-      ?.map((e) => e == null
-          ? null
-          : new Map<String, Map<String, List<List<DateTime>>>>.fromIterables(
-              (e as Map).keys.cast<String>(),
-              (e as Map).values.map((e) =>
-                  e == null ? null : new Map<String, List<List<DateTime>>>.fromIterables((e as Map).keys.cast<String>(), (e as Map).values.map((e) => (e as List)?.map((e) => (e as List)?.map((e) => e == null ? null : DateTime.parse(e as String))?.toList())?.toList())))))
+      ?.map((e) => (e as Map)?.map((k, e) => new MapEntry(
+          k as String,
+          (e as Map)?.map(
+              (k, e) => new MapEntry(k as String, (e as List)?.map((e) => (e as List)?.map((e) => e == null ? null : DateTime.parse(e as String))?.toList())?.toList())))))
       ?.toList()
   ..val = json['val'] == null ? null : new Map<String, bool>.from(json['val'] as Map)
   ..writeNotNull = json['writeNotNull'] as bool
@@ -70,8 +63,8 @@ abstract class _$KitchenSinkSerializerMixin {
   List<DateTime> get dateTimeList;
   Map<dynamic, dynamic> get map;
   Map<String, String> get stringStringMap;
-  Map<String, int> get stringIntMap;
-  Map<String, DateTime> get stringDateTimeMap;
+  Map<dynamic, int> get dynamicIntMap;
+  Map<Object, DateTime> get objectDateTimeMap;
   List<Map<String, Map<String, List<List<DateTime>>>>> get crazyComplex;
   Map<String, bool> get val;
   bool get writeNotNull;
@@ -103,27 +96,20 @@ abstract class _$KitchenSinkSerializerMixin {
         dateTimeList?.map((e) => e?.toIso8601String())?.toList());
     val['map'] = map;
     val['stringStringMap'] = stringStringMap;
-    val['stringIntMap'] = stringIntMap;
-    val['stringDateTimeMap'] = stringDateTimeMap == null
-        ? null
-        : new Map<String, dynamic>.fromIterables(stringDateTimeMap.keys,
-            stringDateTimeMap.values.map((e) => e?.toIso8601String()));
+    val['dynamicIntMap'] = dynamicIntMap;
+    val['objectDateTimeMap'] =
+        objectDateTimeMap?.map((k, e) => new MapEntry(k, e?.toIso8601String()));
     writeNotNull(
         'crazyComplex',
         crazyComplex
-            ?.map((e) => e == null
-                ? null
-                : new Map<String, dynamic>.fromIterables(
-                    e.keys,
-                    e.values.map((e) => e == null
-                        ? null
-                        : new Map<String, dynamic>.fromIterables(
-                            e.keys,
-                            e.values.map((e) => e
-                                ?.map((e) => e
-                                    ?.map((e) => e?.toIso8601String())
-                                    ?.toList())
-                                ?.toList())))))
+            ?.map((e) => e?.map((k, e) => new MapEntry(
+                k,
+                e?.map((k, e) => new MapEntry(
+                    k,
+                    e
+                        ?.map((e) =>
+                            e?.map((e) => e?.toIso8601String())?.toList())
+                        ?.toList())))))
             ?.toList());
     writeNotNull('val', this.val);
     val['writeNotNull'] = this.writeNotNull;

json_serializable/test/test_files/kitchen_sink.non_nullable.dart

@@ -99,8 +99,8 @@ class KitchenSink extends Object
 
   Map map = _defaultMap();
   Map<String, String> stringStringMap = _defaultMap();
-  Map<String, int> stringIntMap = _defaultMap();
-  Map<String, DateTime> stringDateTimeMap = _defaultMap();
+  Map<dynamic, int> dynamicIntMap = _defaultMap();
+  Map<Object, DateTime> objectDateTimeMap = _defaultMap();
 
   @JsonKey(includeIfNull: false)
   List<Map<String, Map<String, List<List<DateTime>>>>> crazyComplex =