faker_gen 0.3.2

Code generator for fake factory functions. Generates fakeClassName() functions for classes annotated with @FakeIt().

faker_gen

A code generator for creating fake data factories in Dart. Annotate your classes with @FakeIt() and get type-safe fake object builders with realistic data powered by faker.

Installation

Add to your pubspec.yaml:

dependencies:
  faker_annotation: ^0.3.0

dev_dependencies:
  faker_gen: ^0.3.0
  build_runner: ^2.4.0

Basic Usage

import 'package:faker_annotation/faker_annotation.dart';

part 'user.g.dart';

@FakeIt()
class User {
  final String name;
  final int age;
  final bool? active;
  
  User({required this.name, required this.age, required this.active});
}

Run the generator:

dart run build_runner build

Use the generated factory:

// Create a fake user with random data
final user = fakeUser();
print(user.name);   // Nasir Lesch
print(user.age);    // 42
print(user.active); // true

// Override specific fields
final customUser = fakeUser(name: 'John', active: null);
print(customUser.name); // John
print(customUser.age);  // 56
print(user.active); // null

// Generate multiple fake users
final users = fakeUser.many(10);
print(users.length); // 10

Annotations

@FakeIt

Marks a class for fake factory generation.

@FakeIt()
class Product {
  final String id;
  final double price;
  Product({required this.id, required this.price});
}

@FakeAs

Generates semantically meaningful fake data for fields.

@FakeIt()
class Person {
  @FakeAs.uuid()
  final String id;
  
  @FakeAs.firstName()
  final String name;
  
  @FakeAs.email()
  final String email;
  
  @FakeAs.latitude()
  final double lat;
  
  @FakeAs.integer(min: 18, max: 65)
  final int age;
  
  @FakeAs.dateTime(minYear: 1990, maxYear: 2000)
  final DateTime birthDate;
  
  Person({...});
}

@FakeWith

Use a custom function for complex/custom fake data:

List<String> fakeTags(Faker f) => f.nextListOf(() => f.nextWord(), maxLength: 5);
dynamic fakeData(Faker f) => f.nextInt();

@FakeIt()
class Article {
  final String title;
  
  @FakeWith(fakeTags)
  final List<String> tags;

  @FakeWith(fakeData)
  final dynamic data;
  
  Article({required this.title, required this.tags, this.data});
}

@FakeValue

Use a constant value for a field:

@FakeIt()
class Config {
  @FakeValue('production')
  final String environment;
  
  @FakeValue(42)
  final int maxRetries;
  
  Config({required this.environment, required this.maxRetries});
}

FakeGenerator

Create reusable, parameterizable generators by extending FakeGenerator<T>. Use them directly as annotations:

class FakeAuthorGenerator extends FakeGenerator<Author> {
  final String? defaultDomain;
  const FakeAuthorGenerator({this.defaultDomain});
  
  @override
  Author generate(Faker faker) => Author(
    name: faker.nextFullName(),
    email: defaultDomain != null
        ? '${faker.nextUsername()}@$defaultDomain'
        : faker.nextEmail(),
  );
}

@FakeIt()
class Article {
  final String title;
  
  @FakeAuthorGenerator(defaultDomain: 'company.com')
  final Author author;
  
  Article({required this.title, required this.author});
}

Faker

The Faker class provides all fake data methods. Use it in @FakeWith functions or standalone:

final f = Faker();

f.nextString();           // Random string
f.nextInt(min: 0, max: 100);  // Random int in range
f.nextDouble();           // Random double 0.0-1.0
f.nextBool();             // Random boolean
f.nextDateTime();         // Random DateTime
f.nextEmail();            // Fake email
f.nextFirstName();        // Fake first name
// ...

Nested Classes

Classes annotated with @FakeIt() are automatically composed:

@FakeIt()
class Address {
  final String city;
  Address({required this.city});
}

@FakeIt()
class Company {
  final String name;
  final Address address;  // Automatically uses fakeAddress()
  Company({required this.name, required this.address});
}

License

MIT