Put null values into serialized output in dart2 generator (#12569)

* Put null values into serialized output in dart2 generator

* Update samples

Author: jld3103

modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache

@@ -90,11 +90,15 @@ class {{{classname}}} {
       {{/isDate}}
     {{/isDateTime}}
     {{#isNullable}}
+    } else {
+      _json[r'{{{baseName}}}'] = null;
     }
     {{/isNullable}}
     {{^isNullable}}
       {{^required}}
         {{^defaultValue}}
+    } else {
+      _json[r'{{{baseName}}}'] = null;
     }
         {{/defaultValue}}
       {{/required}}

samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/api_response.dart

@@ -62,12 +62,18 @@ class ApiResponse {
     final _json = <String, dynamic>{};
     if (code != null) {
       _json[r'code'] = code;
+    } else {
+      _json[r'code'] = null;
     }
     if (type != null) {
       _json[r'type'] = type;
+    } else {
+      _json[r'type'] = null;
     }
     if (message != null) {
       _json[r'message'] = message;
+    } else {
+      _json[r'message'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/category.dart

@@ -51,9 +51,13 @@ class Category {
     final _json = <String, dynamic>{};
     if (id != null) {
       _json[r'id'] = id;
+    } else {
+      _json[r'id'] = null;
     }
     if (name != null) {
       _json[r'name'] = name;
+    } else {
+      _json[r'name'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/order.dart

@@ -84,18 +84,28 @@ class Order {
     final _json = <String, dynamic>{};
     if (id != null) {
       _json[r'id'] = id;
+    } else {
+      _json[r'id'] = null;
     }
     if (petId != null) {
       _json[r'petId'] = petId;
+    } else {
+      _json[r'petId'] = null;
     }
     if (quantity != null) {
       _json[r'quantity'] = quantity;
+    } else {
+      _json[r'quantity'] = null;
     }
     if (shipDate != null) {
       _json[r'shipDate'] = shipDate!.toUtc().toIso8601String();
+    } else {
+      _json[r'shipDate'] = null;
     }
     if (status != null) {
       _json[r'status'] = status;
+    } else {
+      _json[r'status'] = null;
     }
       _json[r'complete'] = complete;
     return _json;

samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/pet.dart

@@ -72,15 +72,21 @@ class Pet {
     final _json = <String, dynamic>{};
     if (id != null) {
       _json[r'id'] = id;
+    } else {
+      _json[r'id'] = null;
     }
     if (category != null) {
       _json[r'category'] = category;
+    } else {
+      _json[r'category'] = null;
     }
       _json[r'name'] = name;
       _json[r'photoUrls'] = photoUrls;
       _json[r'tags'] = tags;
     if (status != null) {
       _json[r'status'] = status;
+    } else {
+      _json[r'status'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/tag.dart

@@ -51,9 +51,13 @@ class Tag {
     final _json = <String, dynamic>{};
     if (id != null) {
       _json[r'id'] = id;
+    } else {
+      _json[r'id'] = null;
     }
     if (name != null) {
       _json[r'name'] = name;
+    } else {
+      _json[r'name'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/user.dart

@@ -118,27 +118,43 @@ class User {
     final _json = <String, dynamic>{};
     if (id != null) {
       _json[r'id'] = id;
+    } else {
+      _json[r'id'] = null;
     }
     if (username != null) {
       _json[r'username'] = username;
+    } else {
+      _json[r'username'] = null;
     }
     if (firstName != null) {
       _json[r'firstName'] = firstName;
+    } else {
+      _json[r'firstName'] = null;
     }
     if (lastName != null) {
       _json[r'lastName'] = lastName;
+    } else {
+      _json[r'lastName'] = null;
     }
     if (email != null) {
       _json[r'email'] = email;
+    } else {
+      _json[r'email'] = null;
     }
     if (password != null) {
       _json[r'password'] = password;
+    } else {
+      _json[r'password'] = null;
     }
     if (phone != null) {
       _json[r'phone'] = phone;
+    } else {
+      _json[r'phone'] = null;
     }
     if (userStatus != null) {
       _json[r'userStatus'] = userStatus;
+    } else {
+      _json[r'userStatus'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/all_of_with_single_ref.dart

@@ -45,9 +45,13 @@ class AllOfWithSingleRef {
     final _json = <String, dynamic>{};
     if (username != null) {
       _json[r'username'] = username;
+    } else {
+      _json[r'username'] = null;
     }
     if (singleRefType != null) {
       _json[r'SingleRefType'] = singleRefType;
+    } else {
+      _json[r'SingleRefType'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/api_response.dart

@@ -62,12 +62,18 @@ class ApiResponse {
     final _json = <String, dynamic>{};
     if (code != null) {
       _json[r'code'] = code;
+    } else {
+      _json[r'code'] = null;
     }
     if (type != null) {
       _json[r'type'] = type;
+    } else {
+      _json[r'type'] = null;
     }
     if (message != null) {
       _json[r'message'] = message;
+    } else {
+      _json[r'message'] = null;
     }
     return _json;
   }

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/capitalization.dart

@@ -96,21 +96,33 @@ class Capitalization {
     final _json = <String, dynamic>{};
     if (smallCamel != null) {
       _json[r'smallCamel'] = smallCamel;
+    } else {
+      _json[r'smallCamel'] = null;
     }
     if (capitalCamel != null) {
       _json[r'CapitalCamel'] = capitalCamel;
+    } else {
+      _json[r'CapitalCamel'] = null;
     }
     if (smallSnake != null) {
       _json[r'small_Snake'] = smallSnake;
+    } else {
+      _json[r'small_Snake'] = null;
     }
     if (capitalSnake != null) {
       _json[r'Capital_Snake'] = capitalSnake;
+    } else {
+      _json[r'Capital_Snake'] = null;
     }
     if (sCAETHFlowPoints != null) {
       _json[r'SCA_ETH_Flow_Points'] = sCAETHFlowPoints;
+    } else {
+      _json[r'SCA_ETH_Flow_Points'] = null;
     }
     if (ATT_NAME != null) {
       _json[r'ATT_NAME'] = ATT_NAME;
+    } else {
+      _json[r'ATT_NAME'] = null;
     }
     return _json;
   }