Field's name reverse mapping

packages/auto_mappr/README.md

@@ -45,12 +45,12 @@ Heavily inspired by [C# AutoMapper][auto_mapper_net_link].
   - [Mapping from source](#mapping-from-source)
   - [Nullability handling](#nullability-handling)
     - [Forced non-nullable field for nullable source](#forced-non-nullable-field-for-nullable-source)
-  - [Type converters](#type-converters)
   - [Generics](#generics)
   - [Library import aliases](#library-import-aliases)
   - [Modules](#modules)
     - [Including](#including)
-    - [Delegating](#delegating) 
+    - [Delegating](#delegating)
+  - [Type converters](#type-converters)
   - [Reverse mapping](#reverse-mapping)
   - [Records](#records)
   - [Works with `equatable`](#works-with-equatable)
@@ -748,8 +748,32 @@ you can use `reverse` option on `MapType`.
 Note that it's your responsibility to make sure those objects
 support normal and reverse mapping
 and to keep them in sync.
+
+When `Field`'s mapping with `from` parameter is used, in `reverse` mapping those properties are automatically switched too.
+
+For example
+
+```dart
+class A {
+  final String a;
+}
+
+class B {
+  final String b;
+}
+
+// Mapping
+MapType<A,B>(fields: [
+  Field('b', from: 'a')
+], reverse: true)
+
+// generated mapping
+A.a mapts to B.b
+B.b maps to A.a
+```
+
 Also note that reverse mapping might not work properly when additional configuration
-such as [whenSourceIsNull] or [constructor] is used.
+such as `whenSourceIsNull` or `constructor` is used.
 
 For more complicated scenarios two separate mappings are recommended instead.
 

packages/auto_mappr/lib/src/generator/auto_mappr_generator.dart

@@ -166,7 +166,21 @@ class AutoMapprGenerator extends GeneratorForAnnotation<annotation.AutoMappr> {
               TypeMapping(
                 source: targetType,
                 target: sourceType,
-                fieldMappings: fieldMappings ?? [],
+                fieldMappings: fieldMappings
+                        ?.map(
+                          (f) => f.from != null
+                              ? FieldMapping(
+                                  field: f.from!,
+                                  from: f.field,
+                                  customExpression: f.customExpression,
+                                  whenNullExpression: f.whenNullExpression,
+                                  ignore: f.ignore,
+                                  ignoreNull: f.ignoreNull,
+                                )
+                              : f,
+                        )
+                        .toList() ??
+                    [],
                 typeConverters: [..._toTypeConverters(mapTypeConverters), ...globalConverters],
                 whenSourceIsNullExpression: whenSourceIsNull,
                 constructor: constructor,

packages/auto_mappr/test/integration/fixture/reverse.dart

@@ -7,6 +7,13 @@ import 'reverse.auto_mappr.dart';
   MapType<PrimitiveDto, Primitive>(reverse: true),
   MapType<UserDto, User>(reverse: true),
   MapType<AddressDto, Address>(reverse: true),
+  MapType<AddressDto, SpecialAddress>(
+    fields: [
+      Field('specialStreet', from: 'street'),
+      Field('specialCity', from: 'city'),
+    ],
+    reverse: true,
+  ),
 ])
 class Mappr extends $Mappr {
   const Mappr();
@@ -77,3 +84,13 @@ class AddressDto extends Equatable {
 
   const AddressDto({required this.street, required this.city});
 }
+
+class SpecialAddress extends Equatable {
+  final String specialStreet;
+  final String specialCity;
+
+  @override
+  List<Object?> get props => [specialStreet, specialCity];
+
+  const SpecialAddress({required this.specialStreet, required this.specialCity});
+}

packages/auto_mappr/test/integration/reverse_test.dart

@@ -93,4 +93,22 @@ void main() {
       );
     });
   });
+
+  group('Reverse mapping with custom fields', () {
+    test('AddressDto to SpecialAddress', () {
+      const dto = fixture.AddressDto(street: 'Street 14', city: 'Wakanda');
+
+      final converted = mappr.convert<fixture.AddressDto, fixture.SpecialAddress>(dto);
+
+      expect(converted, equals(const fixture.SpecialAddress(specialStreet: 'Street 14', specialCity: 'Wakanda')));
+    });
+
+    test('SpecialAddress to AddressDto', () {
+      const dto = fixture.SpecialAddress(specialStreet: 'Street 14', specialCity: 'Wakanda');
+
+      final converted = mappr.convert<fixture.SpecialAddress, fixture.AddressDto>(dto);
+
+      expect(converted, equals(const fixture.AddressDto(street: 'Street 14', city: 'Wakanda')));
+    });
+  });
 }