Validasi

A flexible, composable, and type-safe validation library for Dart & Flutter.

Documentation API Documentation

Installation

To use this package, add validasi as a dependency in your pubspec.yaml file:

dependencies:
  validasi: ^1.0.0-rc.1

Check the pub.dev page for the latest pre-release version.

Quick Usage

To use this library, simply import package:validasi/validasi.dart and the rules from package:validasi/rules.dart. Here's a basic example:

import 'package:validasi/validasi.dart';
import 'package:validasi/rules.dart';

void main() {
  final schema = Validasi.string([
    Rules.nullable<String>(),
    Rules.transform<String>((input) => input?.trim()),
    Rules.string.minLength(3),
    Rules.string.maxLength(16)
  ]);

  final result = schema.validate('   Hello World!   ');
  print("isValid: ${result.isValid}, errors: ${result.errors.map((e) => e.message).join(', ')}, value: ${result.data}");
}

Async Validation

Async rules (like checking email availability against a server) run seamlessly alongside sync rules:

final schema = Validasi.string([
  Rules.required(),
  Rules.string.email(),
  Rules.inlineAsync((email) async {
    final taken = await userRepository.isEmailTaken(email!);
    return !taken;
  }, message: 'Email is already taken'),
]);

final result = await schema.validateAsync('user@example.com');

Container rules (hasFields, forEach, allValues, anyOf) automatically support async children when using validateAsync(). See Async Validation for more.

Validating Complex Data Structures

Map Validation:

final schema = Validasi.map<dynamic>([
  Rules.map.hasFields({
    'name': FieldRules<String>([
      Rules.string.minLength(1),
    ]),
    'age': FieldRules<int>([
      Rules.number.moreThan(0),
    ]),
  }),
]);

final result = schema.validate({'name': 'John', 'age': 30});

List Validation:

final schema = Validasi.list<String>([
  Rules.iterable.forEach<String>([
    Rules.string.minLength(1),
  ]),
]);

final result = schema.validate(['item1', 'item2', 'item3']);

Refer to the examples folder to see more usage samples or see the documentation.

Features

Type-Safe Validation Engine

Validasi provides type-safe validation schemas for various data types:

• Validasi.string() - String validation
• Validasi.number<T>() - Numeric validation (int, double, num)
• Validasi.list<T>() - List/Iterable validation
• Validasi.map<T>() - Map validation
• Validasi.any<T>() - Generic type validation

Built-in Rules

The library comes with comprehensive built-in rules organized by data type. See the documentation for the full list:

• String Rules - alpha, email, url, uuid, regex, and more
• Number Rules - finite, lessThan, moreThan, and more
• List Rules - minLength, maxLength, unique, contains, forEach, and more
• Map Rules - hasFields, hasFieldKeys, allowedKeys, requiredAny, matchesField, and more
• Generic Rules - required, nullable, transform, equals, anyOf, inline, and more

Preprocessing & Transformation

Use withPreprocess to transform input data before validation:

final schema = Validasi.string([Rules.string.minLength(3)])
  .withPreprocess((value) => value.toString());

final result = schema.validate(123); // Converts to "123" then validates

Safe Validation

All validation returns a ValidasiResult object that contains:

• isValid - Boolean indicating validation success
• data - The validated (and potentially transformed) data
• errors - List of validation errors with messages and paths

Nested Validation with Error Paths

Validasi tracks error paths for nested structures, making it easy to identify exactly where validation fails:

final result = schema.validate(complexNestedData);
result.errors.forEach((error) {
  print("Error at ${error.path?.join('.')}: ${error.message}");
});

License

The Validasi Library is licensed under MIT License.

Contribution

We welcome contributions! Here's how to set up the development environment:

Setting Up Development Environment

# Clone the repository
git clone https://github.com/albetnov/validasi
cd validasi

# Install root dependencies (includes melos)
dart pub get

# Install workspace dependencies
dart run melos bootstrap

Running Tests

The test structure in test/ directory mirrors the lib/src structure:

# Run all tests
dart run melos run test

# Run tests for root package only
dart run melos run test:validasi

# Run tests for MCP package only
dart run melos run test:mcp

# Run tests with coverage
dart test --coverage=coverage

# Format coverage report
dart pub global activate coverage
dart pub global run coverage:format_coverage --lcov --in=coverage --out=coverage/lcov.info --report-on=lib