Custom Mapper Annotation #

Annotations for the custom_mapper code generation package.

This package contains only the annotations used by custom_mapper to generate mapping code. It has no dependencies and is lightweight, making it safe to include in your main dependencies without adding bloat to your application.

Features #

• 🏷️ @Mapper - Mark classes for automatic mapping code generation
• 🚫 @IgnoreField - Exclude specific fields from mapping
• 🔄 @DefaultIfNull - Provide default values for null fields
• 📦 Zero Dependencies - Lightweight annotations-only package
• ✅ Type Safe - Full compile-time type checking

Installation #

Add this package to your pubspec.yaml:

dependencies:
  custom_mapper_annotation: ^0.0.2

dev_dependencies:
  custom_mapper: ^0.0.2
  build_runner: ^2.4.13

Annotations #

@Mapper #

The main annotation that marks a class for mapper code generation.

@Mapper(domain: User, toDomain: true, toData: true)
class UserDto {
  final String name;
  final int age;

  const UserDto({required this.name, required this.age});
}

Parameters:

• domain (required): The domain type to map to/from
• toDomain (optional): Generate method to convert to domain (default: true)
• toData (optional): Generate method to convert from domain (default: false)

@IgnoreField #

Marks a field to be ignored during mapping operations.

class UserDto {
  final String name;

  @IgnoreField()
  final String internalId; // Won't be mapped
}

@DefaultIfNull #

Provides a default value when the source field is null.

class UserDto {
  @DefaultIfNull('Unknown')
  final String name; // Uses 'Unknown' if source is null

  @DefaultIfNull(0)
  final int age; // Uses 0 if source is null
}

Usage Example #

import 'package:custom_mapper_annotation/custom_mapper_annotation.dart';

// Domain model
class User {
  final String name;
  final int age;
  final String? email;

  const User({required this.name, required this.age, this.email});
}

// DTO with mapping annotations
@Mapper(domain: User, toDomain: true, toData: true)
class UserDto {
  final String name;

  @DefaultIfNull(18)
  final int age;

  final String? email;

  @IgnoreField()
  final String processingId;

  const UserDto({
    required this.name,
    required this.age,
    this.email,
    required this.processingId,
  });
}

After running dart run build_runner build, you'll get generated extension methods:

// Generated methods (example)
final user = User(name: 'John', age: 30, email: 'john@example.com');
final dto = user.toData(); // Convert to DTO
final backToUser = dto.toDomain(); // Convert back to domain

More Information #

• See the example for complete usage
• Check the main custom_mapper package for code generation
• Visit the GitHub repository for source code

Contributing #

Contributions are welcome! Please read our contributing guidelines and submit pull requests to our GitHub repository.