joelklabo/swiftdatavalidator

Features

• 🎯 Type-safe validation with Swift generics
• 📝 Declarative API for defining validation rules
• 🌍 Localized error messages with recovery suggestions
• 🔧 Built-in validators for common use cases
• 🎨 Custom validation rules for business logic
• 📦 Zero dependencies - pure Swift implementation
• 🚀 Swift 6 ready with full concurrency support
• 📱 Multi-platform - iOS, macOS, tvOS, watchOS, visionOS

Requirements

• Swift 6.0+
• iOS 18.0+ / macOS 15.0+ / tvOS 18.0+ / watchOS 11.0+ / visionOS 2.0+

Installation

Swift Package Manager

Add SwiftDataValidator to your Package.swift file:

dependencies: [
    .package(url: "https://github.com/joelklabo/SwiftDataValidator", from: "1.0.0")
]

Or add it through Xcode:

1. File → Add Package Dependencies...
2. Enter: https://github.com/joelklabo/SwiftDataValidator
3. Click Add Package

Quick Start

1. Make your SwiftData model conform to Validatable:

import SwiftData
import SwiftDataValidator

@Model
final class User: Validatable {
    var name: String = ""
    var email: String = ""
    var age: Int = 0
    
    func validate() -> [ValidationError] {
        var validator = Validator()
        
        validator.validate(field: "name", value: name) { validator in
            validator.required()
            validator.notEmpty()
            validator.maxLength(50)
        }
        
        validator.validate(field: "email", value: email) { validator in
            validator.required()
            validator.matchesEmail()
        }
        
        validator.validate(field: "age", value: age) { validator in
            validator.required()
            validator.range(min: 18, max: 120)
        }
        
        return validator.errors()
    }
}

2. Validate before saving:

let user = User()
user.name = "John Doe"
user.email = "john@example.com"
user.age = 25

let errors = user.validate()
if errors.isEmpty {
    context.insert(user)
    try context.save()
} else {
    // Handle validation errors
    for error in errors {
        print("\(error.field): \(error.localizedDescription)")
        if let suggestion = error.recoverySuggestion {
            print("  → \(suggestion)")
        }
    }
}

Available Validators

String Validators

validator.validate(field: "username", value: username) { validator in
    validator.required()           // Not nil
    validator.notEmpty()          // Not empty or whitespace
    validator.minLength(3)        // Minimum length
    validator.maxLength(20)       // Maximum length
    validator.matchesEmail()      // Valid email format
    validator.matchesURL()        // Valid URL format
    validator.matchesPhoneNumber() // Valid phone number
}

Numeric Validators

validator.validate(field: "age", value: age) { validator in
    validator.required()
    validator.range(min: 0, max: 150)  // Within range
}

Date Validators

validator.validate(field: "birthDate", value: birthDate) { validator in
    validator.required()
    validator.notFuture()  // Not in the future
    validator.notPast()    // Not in the past
}

Field Matching

validator.validate(field: "confirmPassword", value: confirmPassword) { validator in
    validator.required()
    validator.matches(password, fieldName: "password")
}

Custom Validators

validator.validate(field: "username", value: username) { validator in
    validator.custom({ value in
        // Return true if valid
        return value != "admin"
    }, error: .businessRule(reason: "Username 'admin' is reserved"))
}

Advanced Usage

Custom Validation Rules

You can create custom validation rules using the ValidationRule enum:

extension ValidationRule {
    static func mustContainSpecialCharacter() -> ValidationRule {
        .custom(message: "Password must contain at least one special character")
    }
}

// Usage
validator.validate(field: "password", value: password) { validator in
    validator.custom({ password in
        guard let password else { return false }
        let specialCharacters = CharacterSet(charactersIn: "!@#$%^&*()_+-=[]{}|;:,.<>?")
        return password.rangeOfCharacter(from: specialCharacters) != nil
    }, error: .mustContainSpecialCharacter())
}

Validation in SwiftUI

Create a view model that handles validation:

@Observable
final class UserFormViewModel {
    var name = ""
    var email = ""
    var errors: [ValidationError] = []
    
    func validate() {
        let user = User()
        user.name = name
        user.email = email
        errors = user.validate()
    }
    
    func save(in context: ModelContext) throws {
        validate()
        guard errors.isEmpty else { return }
        
        let user = User()
        user.name = name
        user.email = email
        context.insert(user)
        try context.save()
    }
}

Localization

All error messages are localizable. Create a Localizable.strings file and override the default messages:

"email is required" = "Email address is required";
"email must be a valid email address" = "Please enter a valid email address";
"Please provide a value for email" = "Email cannot be left blank";

API Documentation

Full API documentation is available at Swift Package Index.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. Before contributing, please:

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

Make sure all tests pass and add new tests for any new functionality.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Built with ❤️ using Swift 6 and SwiftData

Package Metadata

Repository: joelklabo/swiftdatavalidator

Default branch: main

README: README.md