# Belatuk JSON Serializer  [](https://dart.dev/null-safety) [](https://gitter.im/angel_dart/discussion) [](https://github.com/dart-backend/belatuk-common-utilities/blob/main/packages/json_serializer/LICENSE) **Replacement of `package:json_god` with breaking changes to support NNBD.** The ***new and improved*** definitive solution for JSON in Dart. It supports synchronously transform an object into a JSON string and also deserialize a JSON string back into an instance of any type. ## Installation ```yaml dependencies: platform_json_serializer: ^7.1.0 ``` ## Usage It is recommended to import the library under an alias, i.e., `jsonSerializer`. ```dart import 'package:belatuk_json_serialization/belatuk_json_serialization.dart' as jsonSerializer; ``` ## Serializing JSON Simply call `jsonSerializer.serialize(x)` to synchronously transform an object into a JSON string. ```dart Map map = {"foo": "bar", "numbers": [1, 2, {"three": 4}]}; // Output: {"foo":"bar","numbers":[1,2,{"three":4]"} String json = jsonSerializer.serialize(map); print(json); ``` You can easily serialize classes, too. Belatuk JSON Serializer also supports classes as members. ```dart class A { String foo; A(this.foo); } class B { late String hello; late A nested; B(String hello, String foo) { this.hello = hello; this.nested = A(foo); } } main() { print(jsonSerializer.serialize( B("world", "bar"))); } // Output: {"hello":"world","nested":{"foo":"bar"}} ``` If a class has a `toJson` method, it will be called instead. ## Deserializing JSON Deserialization is equally easy, and is provided through `jsonSerializer.deserialize`. ```dart Map map = jsonSerializer.deserialize('{"hello":"world"}'); int three = jsonSerializer.deserialize("3"); ``` ### Deserializing to Classes Belatuk JSON Serializer lets you deserialize JSON into an instance of any type. Simply pass the type as the second argument to `jsonSerializer.deserialize`. If the class has a `fromJson` constructor, it will be called instead. ```dart class Child { String foo; } class Parent { String hello; Child child = Child(); } main() { Parent parent = jsonSerializer.deserialize('{"hello":"world","child":{"foo":"bar"}}', Parent); print(parent); } ``` **Any JSON-deserializable classes must initializable without parameters. If `Foo()` would throw an error, then you can't use Foo with JSON.** This allows for validation of a sort, as only fields you have declared will be accepted. ```dart class HasAnInt { int theInt; } HasAnInt invalid = jsonSerializer.deserialize('["some invalid input"]', HasAnInt); // Throws an error ``` An exception will be thrown if validation fails.