Provides
Dart Build System builder for generating copyWith
extensions for classes annotated with
copy_with_extension. For more info on this package check out my
blog article.
Usage
In your pubspec.yaml
file:
- Add to
dependencies
sectioncopy_with_extension: ^2.0.2
- Add to
dev_dependencies
sectioncopy_with_extension_gen: ^2.0.2
- Add to
dev_dependencies
sectionbuild_runner: ^2.0.0
- Set
environment
to at least Dart 2.12.0 version like so:">=2.12.0 <3.0.0"
Your pubspec.yaml
should look like so:
name: project_name
description: project description
version: 1.0.0
environment:
sdk: ">=2.12.0 <3.0.0"
dependencies:
...
copy_with_extension: ^2.0.2
dev_dependencies:
...
build_runner: ^2.0.0
copy_with_extension_gen: ^2.0.2
Annotate your class with CopyWith
annotation:
import 'package:copy_with_extension/copy_with_extension.dart';
part 'basic_class.g.dart';
@CopyWith()
class BasicClass {
final String id;
BasicClass({this.id});
}
Make sure that you set the part file as in the example above part 'your_file_name.g.dart';
.
Launch code generation:
flutter pub run build_runner build
The extension will be generated:
// GENERATED CODE - DO NOT MODIFY BY HAND
part of 'basic_class.dart';
// **************************************************************************
// CopyWithGenerator
// **************************************************************************
extension CopyWithExtension on BasicClass {
BasicClass copyWith({
String id,
}) {
return BasicClass(
id: id ?? this.id,
);
}
}
Additional features
Nullifying the class fields:
The copyWith
method ignores any null
values that are passed to it. In order to nullify the class fields, an additional copyWithNull
function can be generated. To achieve this, simply pass an additional parameter to your class annotation @CopyWith(generateCopyWithNull: true)
.
Immutable fields
If you want to prevent a particular field from modifying with copyWith
method you can add an additional annotation like this:
@CopyWithField(immutable: true)
final int myImmutableField;
By adding this annotation you forcing your generated copyWith
to always copy this field as it is, without allowing its modification.