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 pkg: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.

• 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.