The Set of code generators reduce boilerplate code writing.

Installation

Add dependencies to your pubspec.yaml

dependencies:
  boilerplate_annotations:

dev_dependencies:
  boilerplate_generators:
  build_runner:

Generators

• CopyWith
• Props

CopyWith

The code generator for copyWith and copyWithNull methods generation supports deep copy and field ignoring.

Usage

• Annotate a class with the @copyWith annotation
• Add a part file - part 'your_file_name.g.dart'
• Run the build_runner.

Methods copyWith, and copyWithNull will be generated.

part 'address.g.dart';

@copyWith
class Address  {
    final String? street;
    final int? home;
    const Address({this.street, this.home});
}

If you want to disable the copyWithNull method generation, pass "copyWithNull = false" to the CopyWith annotation.

@CopyWith(copyWithNull: false)
class Address  {
  final String? street;
  final int? home;
  const Address({this.street, this.home});
}

copyWith and copyWithNull difference

The copyWith method rejects null.

@copyWith
class Payment {
  final int id;
  final String? description;
  const Payment({required this.id, this.description});
}

const payment = Payment(id: 4, description: 'test',);

print(payment.copyWith(description: null)); // Payment(id:4, description: test)

The copyWithNull method allows a copy with a null value.

@copyWith
class Payment {
  final int id;
  final String? description;
  const Payment({required this.id, this.description});
}

const payment = Payment(id: 4, description: 'test',);

print(payment.copyWithNull(description: null)); // Payment(id:4, description: null)

Deep copy

With deep copy support, you can call copyWith and copyWithNull methods of objects that a class contains and get a new instance of a class with an updated object. A class and objects that a class contains must be annotated with the @copyWith annotation.

@copyWith
class Payment {
final int id;
final String? description;
final Customer? customer;
const Payment({required this.id, this.customer, this.description});
}

@copyWith
class Customer {
final int id;
final String name;
final String surname;
final String? patronymic;
const Customer({
  required this.id,
  required this.name,
  required this.surname,
  this.patronymic,
});
}

const payment = Payment(
id: 4,
customer: Customer(
  id: 1,
  name: 'John',
  surname: 'Dou',
),
);

print(payment.copyWith.customer!(name: 'Bob')); // Payment(id: 4, customer: Customer(id: 1,name: 'Bob',surname: 'Dou'))

Ignore field

If you want a class field to be excluded from copyWith and copyWithNull methods generation, you need to annotate this field with the @copyWithExclude annotation. In this case, it will be impossible to change this field with these methods.

@copyWith
class Payment {
@copyWithExclude
final int id;
final String? description;
final Customer? customer;
const Payment({required this.id, this.customer, this.description});
}

Props

The code generator generates equatable props.

Usage

• Annotate a class with the @props annotation
• Add a part file - part 'your_file_name.g.dart'
• Override the props getter to return the _${your class name}Props(this);
• Run the build_runner.

Generated props will contain all final class fields.

part 'address.g.dart';

@props
class Address extends Equatable {
    final String? street;
    final int? home;
    const Address({this.street, this.home});
}
  @override
  List<Object?> get props => _$AddressProps(this);
}

Super class props

If your class extends from another class that uses Equatable, you need to add props from a superclass. You need to pass superclass props to the superProps parameter.

@props
class First extends Equatable {
  final String data;
  First(this.data);

  @override
  List<Object?> get props => _$FirstProps(this);
}

@props
class Second extends First {
  final String second;
  Second(this.second, String data) : super(data);

  @override
  List<Object?> get props => _$SecondProps(this, superProps: super.props);
}

Ignore field

If you want a class field to be excluded from props generation, you need to annotate this field with the @propsExclude annotation. In this case, props will not contain this field.

@props
class Address extends Equatable {
    @propsExclude
    final String? street;
    final int? home;
    const Address({this.street, this.home});
}
  @override
  List<Object?> get props => _$AddressProps(this);
}