Simplify handling of nullable maps

Author: kevmoo

json_serializable/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.5
+
+* Small change to how nullable `Map` values are deserialized.
+
 ## 0.5.4+1
 
 * Fixed a bug introduced in `0.5.4` in some cases where enum values are nested

json_serializable/lib/src/type_helpers/map_helper.dart

@@ -8,7 +8,6 @@ import '../constants.dart';
 import '../shared_checkers.dart';
 import '../type_helper.dart';
 import '../type_helper_context.dart';
-import '../utils.dart';
 
 class MapHelper extends TypeHelper {
   const MapHelper();
@@ -77,11 +76,11 @@ class MapHelper extends TypeHelper {
       }
     }
 
-    if (valueArgIsAny || simpleJsonTypeChecker.isAssignableFromType(valueArg)) {
-      // No mapping of the values is required!
-
-      var result = 'new Map<String, $valueArg>.from($expression as Map)';
-      return commonNullPrefix(context.nullable, expression, result);
+    if (!context.nullable &&
+        (valueArgIsAny ||
+            simpleJsonTypeChecker.isAssignableFromType(valueArg))) {
+      // No mapping of the values or null check required!
+      return 'new Map<String, $valueArg>.from($expression as Map)';
     }
 
     // In this case, we're going to create a new Map with matching reified

json_serializable/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_serializable
-version: 0.5.4+1
+version: 0.5.5-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/test/kitchen_sink_test_files/kitchen_sink.g.dart

@@ -29,21 +29,17 @@ KitchenSink _$KitchenSinkFromJson(Map json) => new KitchenSink(
       ?.map((e) => e == null ? null : DateTime.parse(e as String))
       ?.toList()
   ..map = json['map'] as Map
-  ..stringStringMap = json['stringStringMap'] == null
-      ? null
-      : new Map<String, String>.from(json['stringStringMap'] as Map)
-  ..dynamicIntMap = json['dynamicIntMap'] == null
-      ? null
-      : new Map<String, int>.from(json['dynamicIntMap'] as Map)
+  ..stringStringMap = (json['stringStringMap'] as Map)
+      ?.map((k, e) => new MapEntry(k as String, e as String))
+  ..dynamicIntMap =
+      (json['dynamicIntMap'] as Map)?.map((k, e) => new MapEntry(k, e as int))
   ..objectDateTimeMap = (json['objectDateTimeMap'] as Map)?.map(
       (k, e) => new MapEntry(k, e == null ? null : DateTime.parse(e as String)))
   ..crazyComplex = (json['crazyComplex'] as List)
       ?.map((e) => (e as Map)?.map((k, e) => new MapEntry(
-          k as String,
-          (e as Map)?.map(
-              (k, e) => new MapEntry(k as String, (e as List)?.map((e) => (e as List)?.map((e) => e == null ? null : DateTime.parse(e as String))?.toList())?.toList())))))
+          k as String, (e as Map)?.map((k, e) => new MapEntry(k as String, (e as List)?.map((e) => (e as List)?.map((e) => e == null ? null : DateTime.parse(e as String))?.toList())?.toList())))))
       ?.toList()
-  ..val = json['val'] == null ? null : new Map<String, bool>.from(json['val'] as Map)
+  ..val = (json['val'] as Map)?.map((k, e) => new MapEntry(k as String, e as bool))
   ..writeNotNull = json['writeNotNull'] as bool
   ..string = json[r'$string'] as String
   ..simpleObject = json['simpleObject'] == null ? null : new SimpleObject.fromJson(json['simpleObject'] as Map)

json_serializable/test/kitchen_sink_test_files/kitchen_sink.wrapped.g.dart

@@ -29,21 +29,17 @@ KitchenSink _$KitchenSinkFromJson(Map json) => new KitchenSink(
       ?.map((e) => e == null ? null : DateTime.parse(e as String))
       ?.toList()
   ..map = json['map'] as Map
-  ..stringStringMap = json['stringStringMap'] == null
-      ? null
-      : new Map<String, String>.from(json['stringStringMap'] as Map)
-  ..dynamicIntMap = json['dynamicIntMap'] == null
-      ? null
-      : new Map<String, int>.from(json['dynamicIntMap'] as Map)
+  ..stringStringMap = (json['stringStringMap'] as Map)
+      ?.map((k, e) => new MapEntry(k as String, e as String))
+  ..dynamicIntMap =
+      (json['dynamicIntMap'] as Map)?.map((k, e) => new MapEntry(k, e as int))
   ..objectDateTimeMap = (json['objectDateTimeMap'] as Map)?.map(
       (k, e) => new MapEntry(k, e == null ? null : DateTime.parse(e as String)))
   ..crazyComplex = (json['crazyComplex'] as List)
       ?.map((e) => (e as Map)?.map((k, e) => new MapEntry(
-          k as String,
-          (e as Map)?.map(
-              (k, e) => new MapEntry(k as String, (e as List)?.map((e) => (e as List)?.map((e) => e == null ? null : DateTime.parse(e as String))?.toList())?.toList())))))
+          k as String, (e as Map)?.map((k, e) => new MapEntry(k as String, (e as List)?.map((e) => (e as List)?.map((e) => e == null ? null : DateTime.parse(e as String))?.toList())?.toList())))))
       ?.toList()
-  ..val = json['val'] == null ? null : new Map<String, bool>.from(json['val'] as Map)
+  ..val = (json['val'] as Map)?.map((k, e) => new MapEntry(k as String, e as bool))
   ..writeNotNull = json['writeNotNull'] as bool
   ..string = json[r'$string'] as String
   ..simpleObject = json['simpleObject'] == null ? null : new SimpleObject.fromJson(json['simpleObject'] as Map)