# json_serializable 4.1.0

Automatically generate code for converting to and from JSON by annotating Dart classes.




## Installing
```
export PUB_HOSTED_URL=https://pub.mirror.p-hatan.ir
flutter pub add 'json_serializable:4.1.0'
```
Published: 2021-03-19T21:12:21.426982Z
Expected archive SHA-256: 04a71e6124f5fd765e88487a19d0cc980b89c6d8e38df7d940e5af622d0ec003

Available in cache; verification: upstream_checksum
## Direct dependencies
- analyzer: >=0.41.2 <2.0.0
- build: ^2.0.0
- build_config: ^0.4.4
- collection: ^1.14.0
- json_annotation: >=4.0.1 <4.1.0
- meta: ^1.3.0
- path: ^1.8.0
- source_gen: ^1.0.0

## Package README (untrusted upstream documentation)
[![Pub Package](https://img.shields.io/pub/v/json_serializable.svg)](https://pub.dev/packages/json_serializable)

Provides [Dart Build System] builders for handling JSON.

The builders generate code when they find members annotated with classes defined
in [package:json_annotation].

- To generate to/from JSON code for a class, annotate it with
  `@JsonSerializable`. You can provide arguments to `JsonSerializable` to
  configure the generated code. You can also customize individual fields by
  annotating them with `@JsonKey` and providing custom arguments. See the table
  below for details on the [annotation values](#annotation-values).

- To generate a Dart field with the contents of a file containing JSON, use the
  `JsonLiteral` annotation.

## Setup

To configure your project for the latest released version of,
`json_serializable` see the [example].

## Example

Given a library `example.dart` with an `Person` class annotated with
`@JsonSerializable()`:

```dart
import 'package:json_annotation/json_annotation.dart';

part 'example.g.dart';

@JsonSerializable()
class Person {
  final String firstName;
  final String lastName;
  final DateTime? dateOfBirth;
  Person({required this.firstName, required this.lastName, this.dateOfBirth});
  factory Person.fromJson(Map<String, dynamic> json) => _$PersonFromJson(json);
  Map<String, dynamic> toJson() => _$PersonToJson(this);
}
```

Building creates the corresponding part `example.g.dart`:

```dart
part of 'example.dart';

Person _$PersonFromJson(Map<String, dynamic> json) {
  return Person(
    firstName: json['firstName'] as String,
    lastName: json['lastName'] as String,
    dateOfBirth: json['dateOfBirth'] == null
        ? null
        : DateTime.parse(json['dateOfBirth'] as String),
  );
}

Map<String, dynamic> _$PersonToJson(Person instance) => <String, dynamic>{
      'firstName': instance.firstName,
      'lastName': instance.lastName,
      'dateOfBirth': instance.dateOfBirth?.toIso8601String(),
    };
```

# Annotation values

The only annotation required to use this package is `@JsonSerializable`. When
applied to a class (in a correctly configured package), `toJson` and `fromJson`
code will be generated when you build. There are three ways to control how code
is generated:

1. Set properties on `@JsonSerializable`.
2. Add a `@JsonKey` annotation to a field and set properties there.
3. Add configuration to `build.yaml` – [see below](#build-configuration).

| `build.yaml` key           | JsonSerializable                            | JsonKey                     |
| -------------------------- | ------------------------------------------- | --------------------------- |
| any_map                    | [JsonSerializable.anyMap]                   |                             |
| checked                    | [JsonSerializable.checked]                  |                             |
| create_factory             | [JsonSerializable.createFactory]            |                             |
| create_to_json             | [JsonSerializable.createToJson]             |                             |
| disallow_unrecognized_keys | [JsonSerializable.disallowUnrecognizedKeys] |                             |
| explicit_to_json           | [JsonSerializable.explicitToJson]           |                             |
| field_rename               | [JsonSerializable.fieldRename]              |                             |
| generic_argument_factories | [JsonSerializable.genericArgumentFactories] |                             |
| ignore_unannotated         | [JsonSerializable.ignoreUnannotated]        |                             |
| include_if_null            | [JsonSerializable.includeIfNull]            | [JsonKey.includeIfNull]     |
|                            |                                             | [JsonKey.defaultValue]      |
|                            |                                             | [JsonKey.disallowNullValue] |
|                            |                                             | [JsonKey.fromJson]          |
|                            |                                             | [JsonKey.ignore]            |
|                            |                                             | [JsonKey.name]              |
|                            |                                             | [JsonKey.required]          |
|                            |                                             | [JsonKey.toJson]            |
|                            |                                             | [JsonKey.unknownEnumValue]  |

[JsonSerializable.anyMap]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/anyMap.html
[JsonSerializable.checked]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/checked.html
[JsonSerializable.createFactory]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/createFactory.html
[JsonSerializable.createToJson]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/createToJson.html
[JsonSerializable.disallowUnrecognizedKeys]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/disallowUnrecognizedKeys.html
[JsonSerializable.explicitToJson]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/explicitToJson.html
[JsonSerializable.fieldRename]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/fieldRename.html
[JsonSerializable.genericArgumentFactories]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/genericArgumentFactories.html
[JsonSerializable.ignoreUnannotated]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/ignoreUnannotated.html
[JsonSerializable.includeIfNull]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonSerializable/includeIfNull.html
[JsonKey.includeIfNull]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/includeIfNull.html
[JsonKey.defaultValue]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/defaultValue.html
[JsonKey.disallowNullValue]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/disallowNullValue.html
[JsonKey.fromJson]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/fromJson.html
[JsonKey.ignore]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/ignore.html
[JsonKey.name]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/name.html
[JsonKey.required]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/required.html
[JsonKey.toJson]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/toJson.html
[JsonKey.unknownEnumValue]: https://pub.dev/documentation/json_annotation/4.0.1/json_annotation/JsonKey/unknownEnumValue.html

> Note: every `JsonSerializable` field is configurable via `build.yaml` –
> see the table for the corresponding key.
> If you find you want all or most of your classes with the same configuration,
> it may be easier to specify values once in the YAML file. Values set
> explicitly on `@JsonSerializable` take precedence over settings in
> `build.yaml`.

> Note: There is some overlap between fields on `JsonKey` and
> `JsonSerializable`. In these cases, if a value is set explicitly via `JsonKey`
> it will take precedence over any value set on `JsonSerializable`.  

# Build configuration

Besides setting arguments on the associated annotation classes, you can also
configure code generation by setting values in `build.yaml`.

```yaml
targets:
  $default:
    builders:
      json_serializable:
        options:
          # Options configure how source code is generated for every
          # `@JsonSerializable`-annotated class in the package.
          #
          # The default value for each is listed.
          any_map: false
          checked: false
          create_factory: true
          create_to_json: true
          disallow_unrecognized_keys: false
          explicit_to_json: false
          field_rename: none
          generic_argument_factories: false
          ignore_unannotated: false
          include_if_null: true
```

[example]: https://github.com/google/json_serializable.dart/tree/master/example
[dart build system]: https://github.com/dart-lang/build
[package:json_annotation]: https://pub.dev/packages/json_annotation

## Changelog
## 4.1.0

- Implementation is now null-safe.
- Correctly handle nullable generic fields (`T?`) with
  `genericArgumentFactories`.

- `type_helper.dart` - **BREAKING changes**
  - The API is now null-safe.
  - new `KeyConfig` class replaces `JsonKey`.
  - new `ClassConfig` class replaces `JsonSerializable`.

## 4.0.3

- Correctly handle nullable values with `genericArgumentFactories`.
- Require the latest `package:build`.

## 4.0.2

- Correctly handle nullable `Map` and `Iterable` JSON types exposed by both
  class- and function-based converters.

## 4.0.1

- Allow latest `package:analyzer`.

## 4.0.0

- Requires Dart 2.12 or greater.
- Generates null-safe code.
  - The `nullable` field on `JsonKey` ignored. The nullability of a field is now
    determined by the Dart type system.
- **BREAKING** `bool defaultProvided` arg added to `TypeHelper.deserialize`.
  _Only applies to code using `TypeHelper` directly._

## 3.5.1

- Improved error messages for unsupported types.
- `package:json_serializable/type_helper.dart`
  - Made the third parameter to `UnsupportedTypeError` positional (optional).
- Require `package:analyzer` `>=0.39.0 <0.42.0`.

## 3.5.0

- Added support for populating generic helper functions for fields with generic
  type parameters.
- Added support for `JsonSerializable.genericArgumentFactories`. This adds extra
  parameters to generated `fromJson` and/or `toJson` functions to support
  encoding and decoding generic types.

  For example, the generated code for

  ```dart
  @JsonSerializable(genericArgumentFactories: true)
  class Response<T> {
    int status;
    T value;
  }
  ```

  Looks like

  ```dart
  Response<T> _$ResponseFromJson<T>(
    Map<String, dynamic> json,
    T Function(Object json) fromJsonT,
  ) {
    return Response<T>()
      ..status = json['status'] as int
      ..value = fromJsonT(json['value']);
  }

  Map<String, dynamic> _$ResponseToJson<T>(
    Response<T> instance,
    Object Function(T value) toJsonT,
  ) =>
      <String, dynamic>{
        'status': instance.status,
        'value': toJsonT(instance.value),
      };
  ```

- `JsonKey.unknownEnumValue`: Added support for `Iterable`, `List`, and `Set`.
- Require `package:analyzer` `>=0.39.0 <0.41.0`.

## 3.4.1

- Support properties where the getter is defined in a class with a corresponding
  setter in a super type.

## 3.4.0

- `JsonKey.defaultValue`
  - Added support for `double.infinity`, `double.negativeInfinity`, and
    `double.nan`.
  - Added support for `Set` literals.
- Require at least Dart `2.7.0`.

## 3.3.0

- Add support for fields annotated subclasses of `JsonKey`.
- Export the following `TypeHelper` implementations and interfaces in
  `package:json_serializable/type_helper.dart`:
  - `DurationHelper`
  - `TypeHelperContextWithConfig`

## 3.2.5

- Fix lint affecting `pub.dev` score.

## 3.2.4

- Require `package:analyzer` `^0.39.0`.

## 3.2.3

- Bug fix for analyzer 0.38.5.

## 3.2.2

- Support `JsonConverter` annotations on property getters

## 3.2.1

- Support `package:analyzer` `>=0.33.3 <0.39.0`

## 3.2.0

- Require `package:json_annotation` `^3.0.0`.
- Added support for `JsonSerializable.ignoreUnannotated`.
- Added support for `JsonKey.unknownEnumValue`.
- Small change to how `enum` support code is generated.
- Require at least Dart `2.3.0`.

## 3.1.0

- Support `Map` keys of type `int`, `BigInt`, `DateTime`, and `Uri`.
- Trailing commas are now added to generated constructor arguments and the
  elements in `Map` literals.
- Support `package:analyzer` `>=0.33.3 <0.38.0`

## 3.0.0

This release is entirely **BREAKING** changes. It removes underused features
that added disproportionate complexity to this package. This cleanup should ease
future feature work.

- Removed support for `JsonSerializable.useWrappers`.
- Removed support for `JsonSerializable.generateToJsonFunction`.
- Removed support for `encodeEmptyCollection`.
- If a field has a conversion function defined – either `JsonKey.toJson` or a
  custom `JsonConverter` annotation – don't intercept `null` values, even if
  `nullable` is explicitly set to `false`. This allows these functions to
  provide alternative values for `null` – such as an empty collection – which
  replaces the functionality provided by `encodeEmptyCollection`.
  - **NOTE: this is SILENTLY BREAKING.** There is no corresponding deprecation
    for this change. If you use converters, please make sure to test your code!

## 2.3.0

- Added `pascal` as an additional `fieldRename` option.

## 2.2.3

- Removed special handling of undefined types due to changes in
  `package:analyzer`. These types are now treated as `dynamic`.

## 2.2.2

- Require at least Dart `2.2.0`.
- Allow `build_config` `0.4.x`.

## 2.2.1

- Fixed an error when a property/field is defined in a `mixin`.

## 2.2.0

- If a field has a conversion function defined – either `JsonKey.toJson` or a
  custom `JsonConverter` annotation – handle the case where the function returns
  `null` and both `nullable` and `includeIfNull` are `false`.

## 2.1.2

- Support `package:json_annotation` `>=2.1.0 <2.3.0`.

## 2.1.1

- Support `package:analyzer` `>=0.33.3 <0.37.0`

## 2.1.0

- Require at least Dart `2.1.1`.

- Added support for `encodeEmptyCollection` on `JsonKey` and `JsonSerializable`.

- Added support for `BigInt`.

- Added `BigIntTypeHelper` to `type_helper.dart` library.

- Provide a more helpful error if the builder is improperly configured.

## 2.0.3

- When invoking a `fromJson` constructor on a field type, generate a conversion
  expression derived from the the constructor parameter type.

- Be more strict about the supported `List`, `Set`, or `Map` types. This may
  causes errors to be raised in cases where invalid code was generated before.
  It also allows implementations of these types to add a `fromJson` constructor
  to support custom decoding.

- Small change to the whitespace around converted maps to improve a very slow
  path when formatting generated code.

## 2.0.2

- Log warnings when `JsonKey.defaultValue` is set with other fields.

  - With `toJson`: use `nullable: false` instead of `defaultValue`.
  - With both `disallowNullValue` and `required` set to `true`.

- Avoid no-op call to `map` when decoding a field of type `Set`.

- Support `package:analyzer` `>=0.33.3 <0.36.0`

## 2.0.1

- Support `package:analyzer` v0.34.0.

## 2.0.0

- Support all `build.yaml` configuration options on classes by adding a number
  of fields to `JsonSerializable`: `anyMap`, `checked`, `explicitToJson`,
  `generateToJsonFunction`, and `useWrappers`.

- Support decode/encode of `dart:core` `Duration`

- Code generated for fields and classes annotated with `JsonConverter` instances
  now properly handles nullable fields.

- Build configuration

  - You can now configure all settings exposed by the `JsonSerializable`
    annotation within `build.yaml`.

  - **BREAKING** Unsupported options defined in `build.yaml` will cause
    exceptions instead of being logged and ignored.

- `json_serializable.dart`

  - **BREAKING** `JsonSerializableGenerator` now exposes a `config` property of
    type `JsonSerializable` instead of individual properties for `checked`,
    `anyMay`, etc. This will affect anyone creating or using this class via
    code.

- `type_helper.dart`

  - **BREAKING** `SerializeContext` and `DeserializeContext` have been replaced
    with new `TypeHelperContext` class.

  - `TypeHelper` now has a type argument allowing implementors to specify a
    specific implementation of `TypeHelperContext` for calls to `serialize` and
    `deserialize`. Many of the included `TypeHelper` implementations have been
    updated to indicate they expect more information from the source generator.

## 1.5.1

- Support the latest `package:analyzer`.

## 1.5.0

- Added support for `JsonConvert` annotation on fields.

## 1.4.0

- `type_helper.dart`

  - `TypeHelper` `serialize` and `deserialize` have return type `Object` instead
    of `String`. This allows coordination between instances to support more
    advanced features – like using the new `LambdaResult` class to avoid
    creating unnecessary lambdas. When creating `TypeHelper` implementations,
    handle non-`String` results by calling `toString()` on unrecognized values.

- Declare support for `package:build` version `1.x.x`.

## 1.3.0

- Add support for types annotated with classes that extend `JsonConverter` from
  `package:json_annotation`.

- Export the following `TypeHelper` implementations in
  `package:json_serializable/type_helper.dart`: `ConvertHelper`, `EnumHelper`,
  `IterableHelper`, `JsonConverterHelper`, `MapHelper`, `ValueHelper`

- Added support for `Set` type as a target.

## 1.2.1

- Added back `const` for maps generated with `checked: true` configuration.

## 1.2.0

- Now throws `InvalidGenerationSourceError` instead of `UnsupportedError` for
  some classes of constructor errors.

- Supports class-static functions for `toJson` and `fromJson` on `JsonKey`.

- Provide a warning about ignored setter-only properties instead of crashing.

- Added back `const` for lists generated with `disallowUnrecognizedKeys`,
  `required`, and `disallowNullValue`.

- Fixed a bug when `disallowUnrecognizedKeys` is enabled.

- Fixed a number of issues when dealing with inherited properties.

## 1.1.0

- Added support for automatically converting field names to JSON map keys as
  `kebab-case` or `snake_case` with a new option on the `JsonSerializable`
  annotation.

## 1.0.1

- Explicit `new` and `const` are no longer generated.

## 1.0.0

- **BREAKING** By default, code generated to support `toJson` now creates a
  top-level function instead of a mixin. The default for the
  `generate_to_json_function` is now `true`. To opt-out of this change, set
  `generate_to_json_function` to `false`.

- Now supports changing the serialized values of enums using `JsonValue`.

  ```dart
  enum AutoApply {
    none,
    dependents,
    @JsonValue('all_packages')
    allPackages,
    @JsonValue('root_package')
    rootPackage
  }
  ```

- `JsonSerializableGenerator.generateForAnnotatedElement` now returns
  `Iterable<String>` instead of `String`.

- `SerializeContext` and `DeserializeContext` now have an `addMember` function
  which allows `TypeHelper` instances to add additional members when handling a
  field. This is useful for generating shared helpers, for instance.

- **BREAKING** The `header` option is no longer supported and must be removed
  from `build.yaml`.

- If a manual build script is used the `json_serializable` builder must be
  switched to `hideOutput: true`, and the `combiningBuilder` from `source_gen`
  must be included following this builder. When using a generated build script
  with `pub run build_runner` or `webdev` this is handled automatically.

## 0.5.8+1

- Support the Dart 2.0 stable release.

## 0.5.8

- Small fixes to support Dart 2 runtime semantics.

- Support serializing types provided by platform-specific libraries (such as
  Flutter) if they use custom convert functions.

## 0.5.7

- Added support for `JsonKey.required`.

  - When `true`, generated code throws a `MissingRequiredKeysException` if the
    key does not exist in the JSON map used to populate the annotated field.
  - Will be captured and wrapped in a `CheckedFromJsonException` if `checked` is
    enabled in `json_serializable`.

- Added `JsonKey.disallowNullValue`.

  - When `true`, generated code throws a `DisallowedNullValueException` if the
    corresponding keys exist in in the JSON map, but it's value is null.
  - Will be captured and wrapped in a `CheckedFromJsonException` if `checked` is
    enabled in `json_serializable`.

- Added support for `Uri` conversion.

- Added missing `checked` parameter to the
  `JsonSerializableGenerator.withDefaultHelpers` constructor.

- Added `explicit_to_json` configuration option.

  - See `JsonSerializableGenerator.explicitToJson` for details.

- Added `generate_to_json_function` configuration option.
  - See `JsonSerializableGenerator.generateToJsonFunction` for details.

## 0.5.6

- Added support for `JsonSerializable.disallowUnrecognizedKeys`.
  - Throws an `UnrecognizedKeysException` if it finds unrecognized keys in the
    JSON map used to populate the annotated field.
  - Will be captured and wrapped in a `CheckedFromJsonException` if `checked` is
    enabled in `json_serializable`.
- All `fromJson` constructors now use block syntax instead of fat arrows.

## 0.5.5

- Added support for `JsonKey.defaultValue`.

- `enum` deserialization now uses helpers provided by `json_annotation`.

- Small change to how nullable `Map` values are deserialized.

- Small whitespace changes to `JsonLiteral` generation to align with `dartfmt`.

- Improve detection of `toJson` and `fromJson` in nested types.

## 0.5.4+1

- Fixed a bug introduced in `0.5.4` in some cases where enum values are nested
  in collections.

## 0.5.4

- Add `checked` configuration option. If `true`, generated `fromJson` functions
  include extra checks to validate proper deserialization of types.

- Added `any_map` to configuration. Allows `fromJson` code to support dynamic
  `Map` instances that are not explicitly `Map<String, dynaimc>`.

- Added support for classes with type arguments.

- Use `Map.map` for more map conversions. Simplifies generated code and fixes a
  subtle issue when the `Map` key type is `dynamic` or `Object`.

## 0.5.3

- Require the latest version of `package:analyzer` - `v0.32.0`.

- If `JsonKey.fromJson` function parameter is `Iterable` or `Map` with type
  arguments of `dynamic` or `Object`, omit the arguments when generating a cast.
  `_myHelper(json['key'] as Map)` instead of
  `_myHelper(json['key'] as Map<dynamic, dynamic>)`.

- `JsonKey.fromJson`/`.toJson` now support functions with optional arguments.

## 0.5.2

- If `JsonKey.fromJson`/`toJson` are set, apply them before any custom or
  default `TypeHelper` instances. This allows custom `DateTime` parsing, by
  preempting the existing `DateTime` `TypeHelper`.

## 0.5.1

- Support new `fromJson` and `toJson` fields on `JsonKey`.

- Use `log` exposed by `package:build`. This requires end-users to have at least
  `package:build_runner` `^0.8.2`.

- Updated minimum `package:source_gen` dependency to `0.8.1` which includes
  improved error messages.

## 0.5.0

- **BREAKING** Removed deprecated support for `require_library_directive` /
  `requireLibraryDirective` in `build_runner` configuration.

- **BREAKING** Removed the deprecated `generators.dart` library.

- **BREAKING** Removed `jsonPartBuilder` function from public API.

- Support the latest `package:source_gen`.

- Private and ignored fields are now excluded when generating serialization and
  deserialization code by using `@JsonKey(ignore: true)`.

- Throw an exception if a private field or an ignored field is referenced by a
  required constructor argument.

- More comprehensive escaping of string literals.

### `package:json_serializable/type_helper.dart`

- **Breaking** The `nullable` parameter on `TypeHelper.serialize` and
  `.deserialize` has been removed. It is now exposed in `SerializeContext` and
  `DeserializeContext` abstract classes as a read-only property.

- **Potentially Breaking** The `metadata` property on `SerializeContext` and
  `DeserializeContext` is now readonly. This would potentially break code that
  extends these classes – which is not expected.

## 0.4.0

- **Potentially Breaking** Inherited fields are now processed and used when
  generating serialization and deserialization code. There is a possibility that
  the generated code may change in undesired ways for classes annotated for
  `v0.3`.

- Avoid unnecessary braces in string escapes.

- Use single quotes when generating code.

## 0.3.2

- The `require_library_directive` option now defaults to `false`. The option
  will be removed entirely in `0.4.0`.

## 0.3.1+2

- Support the latest version of the `analyzer` package.

## 0.3.1+1

- Expanded `package:build` support to allow version `0.12.0`.

## 0.3.1

- Add a `build.yaml` so the builder can be consumed by users of `build_runner`
  version 0.7.0.

- Now requires a Dart `2.0.0-dev` release.

## 0.3.0

- **NEW** top-level library `json_serializable.dart`.

  - Replaces now deprecated `generators.dart` to access
    `JsonSerializableGenerator` and `JsonLiteralGenerator`.

  - Adds the `jsonPartBuilder` function to make it easy to create a
    `PartBuilder`, without creating an explicit dependency on `source_gen`.

- **BREAKING** `UnsupportedTypeError` added a new required constructor argument:
  `reason`.

- **BREAKING** The deprecated `annotations.dart` library has been removed. Use
  `package:json_annotation` instead.

- **BREAKING** The arguments to `TypeHelper` `serialize` and `deserialize` have
  changed.

  - `SerializeContext` and `DeserializeContext` (new classes) are now passed
    instead of the `TypeHelperGenerator` typedef (which has been deleted).

- `JsonSerializableGenerator` now supports an optional `useWrappers` argument
  when generates and uses wrapper classes to (hopefully) improve the speed and
  memory usage of serialization – at the cost of more code.

  **NOTE**: `useWrappers` is not guaranteed to improve the performance of
  serialization. Benchmarking is recommended.

- Make `null` field handling smarter. If a field is classified as not
  `nullable`, then use this knowledge when generating serialization code – even
  if `includeIfNull` is `false`.

## 0.2.5

- Throw an exception if a duplicate JSON key is detected.

- Support the `nullable` field on the `JsonSerializable` class annotation.

## 0.2.4+1

- Throw a more helpful error when a constructor is missing.

## 0.2.4

- Moved the annotations in `annotations.dart` to `package:json_annotations`.

  - Allows package authors to release code that has the corresponding
    annotations without requiring package users to inherit all of the transitive
    dependencies.

- Deprecated `annotations.dart`.

## 0.2.3

- Write out `toJson` methods more efficiently when the first fields written are
  not intercepted by the null-checking method.

## 0.2.2+1

- Simplify the serialization of `Map` instances when no conversion is required
  for `values`.

- Handle `int` literals in JSON being assigned to `double` fields.

## 0.2.2

- Enable support for `enum` values.
- Added `asConst` to `JsonLiteral`.
- Improved the handling of Dart-specific characters in JSON strings.

## 0.2.1

- Upgrade to `package:source_gen` v0.7.0

## 0.2.0+1

- When serializing classes that implement their own `fromJson` constructor,
  honor their constructor parameter type.

## 0.2.0

- **BREAKING** Types are now segmented into their own libraries.

  - `package:json_serializable/generators.dart` contains `Generator`
    implementations.

  - `package:json_serializable/annotations.dart` contains annotations. This
    library should be imported with your target classes.

  - `package:json_serializable/type_helpers.dart` contains `TypeHelper` classes
    and related helpers which allow custom generation for specific types.

- **BREAKING** Generation fails for types that are not a JSON primitive or that
  do not explicitly supports JSON serialization.

- **BREAKING** `TypeHelper`:

  - Removed `can` methods. Return `null` from `(de)serialize` if the provided
    type is not supported.

  - Added `(de)serializeNested` arguments to `(de)serialize` methods allowing
    generic types. This is how support for `Iterable`, `List`, and `Map` is
    implemented.

- **BREAKING** `JsonKey.jsonName` was renamed to `name` and is now a named
  parameter.

- Added support for optional, non-nullable fields.

- Added support for excluding `null` values when generating JSON.

- Eliminated all implicit casts in generated code. These would end up being
  runtime checks in most cases.

- Provide a helpful error when generation fails due to undefined types.

## 0.1.0+1

- Fix homepage in `pubspec.yaml`.

## 0.1.0

- Split off from [source_gen](https://pub.dev/packages/source_gen).

- Add `/* unsafe */` comments to generated output likely to be unsafe.

- Support (de)serializing values in `Map`.

- Fix ordering of fields when they are initialized via constructor.

- Don't use static members when calculating fields to (de)serialize.







 
