mostly working

Author: kevmoo

json_annotation/lib/src/json_serializable.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:collection';
+
 class JsonSerializable {
   final bool createFactory;
   final bool createToJson;
@@ -50,3 +52,24 @@ class JsonKey {
       : this.nullable = nullable ?? true,
         this.includeIfNull = includeIfNull;
 }
+
+// TODO(kevmoo): Add documentation
+abstract class JsonMapWrapper extends MapBase<String, dynamic> {
+  /// This operation is not supported by an unmodifiable map.
+  @override
+  void operator []=(String key, dynamic value) {
+    throw new UnsupportedError('Cannot modify unmodifiable map.');
+  }
+
+  /// This operation is not supported by an unmodifiable map.
+  @override
+  void clear() {
+    throw new UnsupportedError('Cannot modify unmodifiable map.');
+  }
+
+  /// This operation is not supported by an unmodifiable map.
+  @override
+  dynamic remove(Object key) {
+    throw new UnsupportedError('Cannot modify unmodifiable map.');
+  }
+}

json_annotation/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_annotation
-version: 0.2.0
+version: 0.2.1-dev
 description: Annotations for the json_serializable package
 homepage: https://github.com/dart-lang/json_serializable
 author: Dart Team <misc@dartlang.org>

json_serializable/example/example.g.dart

@@ -36,6 +36,8 @@ class JsonSerializableGenerator
 
   final List<TypeHelper> _typeHelpers;
 
+  final bool _doNewThing = true;
+
   /// Creates an instance of [JsonSerializableGenerator].
   ///
   /// If [typeHelpers] is not provided, two built-in helpers are used:
@@ -117,10 +119,13 @@ class JsonSerializableGenerator
     }
 
     if (annotation.read('createToJson').boolValue) {
+      var mixClassName = '${prefix}SerializerMixin';
+      var helpClassName = '${prefix}JsonMapWrapper';
+
       //
       // Generate the mixin class
       //
-      buffer.writeln('abstract class ${prefix}SerializerMixin {');
+      buffer.writeln('abstract class $mixClassName {');
 
       // write copies of the fields - this allows the toJson method to access
       // the fields of the target class
@@ -129,19 +134,84 @@ class JsonSerializableGenerator
         buffer.writeln('  ${field.type} get ${field.name};');
       }
 
-      var includeIfNull = annotation.read('includeIfNull').boolValue;
+      var classIncludeIfNull = annotation.read('includeIfNull').boolValue;
 
-      buffer.writeln('  Map<String, dynamic> toJson() ');
-      if (fieldsList.every((e) => _includeIfNull(e, includeIfNull))) {
-        // write simple `toJson` method that includes all keys...
-        _writeToJsonSimple(buffer, fields.values);
+      buffer.write('  Map<String, dynamic> toJson() ');
+
+      if (_doNewThing) {
+        buffer.writeln('=> new $helpClassName(this);');
       } else {
-        // At least one field should be excluded if null
-        _writeToJsonWithNullChecks(buffer, fields.values, includeIfNull);
+        if (fieldsList.every((e) => _includeIfNull(e, classIncludeIfNull))) {
+          // write simple `toJson` method that includes all keys...
+          _writeToJsonSimple(buffer, fields.values);
+        } else {
+          // At least one field should be excluded if null
+          _writeToJsonWithNullChecks(buffer, fields.values, classIncludeIfNull);
+        }
       }
 
       // end of the mixin class
-      buffer.write('}');
+      buffer.writeln('}');
+
+      if (_doNewThing) {
+        buffer.writeln();
+        //
+        // Generate the Map helper class
+        //
+        // TODO(kevmoo): write JsonMapWrapper if annotation lib is prefix-imported
+        buffer.writeln('''class $helpClassName extends JsonMapWrapper {
+  final $mixClassName _v;
+  $helpClassName(this._v);
+''');
+
+        if (fieldsList.every((e) => _includeIfNull(e, classIncludeIfNull))) {
+          // write simple `toJson` method that includes all keys...
+          //_writeToJsonSimple(buffer, fields);
+
+          var jsonKeys = fields.values.map(_safeNameAccess).join(', ');
+
+          // TODO(kevmoo): maybe put this in a static field instead?
+          //               const lists have unfortunate overhead
+          buffer.writeln('''  @override
+  Iterable<String> get keys => const [${jsonKeys}];
+''');
+        } else {
+          // At least one field should be excluded if null
+          //_writeToJsonWithNullChecks(buffer, fields, includeIfNull);
+          buffer.writeln('@override\nIterable<String> get keys sync* {');
+
+          for (var field in fields.values) {
+            var nullCheck = !_includeIfNull(field, classIncludeIfNull);
+            if (nullCheck) {
+              buffer.writeln('if (_v.${field.name} != null) {');
+            }
+            buffer.writeln('yield ${_safeNameAccess(field)};');
+            if (nullCheck) {
+              buffer.writeln('}');
+            }
+          }
+
+          buffer.writeln('}\n');
+        }
+
+        buffer.writeln('''@override
+dynamic operator [](Object key) {
+if (key is String) {
+switch(key) {
+''');
+
+        for (var field in fields.values) {
+          var valueAccess = '_v.${field.name}';
+          buffer.write('''case ${_safeNameAccess(field)}:
+            return ${_serializeField(field, accessOverride:  valueAccess)};''');
+        }
+
+        buffer.writeln('''
+  }}
+  return null;
+}''');
+      }
+      buffer.writeln('}');
     }
 
     return buffer.toString();

json_serializable/lib/src/json_serializable_generator.dart

@@ -12,7 +12,7 @@ dependencies:
 
   # Use a tight version constraint to ensure that a constraint on
   # `json_annotation`. Properly constrains all features it provides.
-  json_annotation: '>=0.2.0 <0.2.1'
+  json_annotation: '>=0.2.1 <0.2.2'
   path: ^1.3.2
   source_gen: ^0.7.0
 dev_dependencies:
@@ -21,3 +21,7 @@ dev_dependencies:
   collection: ^1.14.0
   dart_style: ^1.0.0
   test: ^0.12.3
+
+dependency_overrides:
+  json_annotation:
+    path: ../json_annotation