Validator is a modern, lightweight Swift framework that provides elegant and type-safe input validation. Built with Swift's powerful type system, it seamlessly integrates with both UIKit and SwiftUI, making form validation effortless across all Apple platforms.
✨ Type-Safe Validation - Leverages Swift's type system for compile-time safety
🎯 Rich Rule Set - Built-in validators for common use cases
🔧 Extensible - Easy to create custom validation rules
📱 UIKit Integration - First-class support for UITextField and other UIKit components
🎨 SwiftUI Native - Property wrappers and view modifiers for declarative validation
📋 Form Management - Validate multiple fields with centralized state management
⚡ Lightweight - Minimal footprint with zero dependencies
🧪 Well Tested - Comprehensive test coverage
- Requirements
- Installation
- Quick Start
- Usage
- Built-in Validators
- Custom Validators
- Examples
- Communication
- Contributing
- License
| Platform | Minimum Version |
|---|---|
| iOS | 16.0+ |
| macOS | 13.0+ |
| tvOS | 16.0+ |
| watchOS | 9.0+ |
| visionOS | 1.0+ |
| Xcode | 15.3+ |
| Swift | 5.10+ |
The package contains two libraries: ValidatorCore encompasses all validation logic and predefined validators, while ValidatorUI implements extensions for integrating the validator into UI objects. It supports both SwiftUI and UIKit.
Add the following dependency to your Package.swift:
dependencies: [ .package(url: "https://github.com/space-code/validator.git", from: "1.3.0") ]Or add it through Xcode:
- File > Add Package Dependencies
- Enter package URL:
https://github.com/space-code/validator.git - Select version requirements
import ValidatorCore let validator = Validator() let result = validator.validate( input: "user@example.com", rule: RegexValidationRule( pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}", error: "Invalid email address" ) ) switch result { case .valid: print("✅ Valid input") case .invalid(let errors): print("❌ Validation failed: \(errors.map(\.message))") }The framework provides two main libraries:
- ValidatorCore - Core validation logic and predefined validators
- ValidatorUI - UI integration for UIKit and SwiftUI
Validate any input with the Validator class:
import ValidatorCore let validator = Validator() let result = validator.validate( input: "password123", rule: LengthValidationRule( min: 8, error: "Password must be at least 8 characters" ) )Import ValidatorUI to add validation to UIKit components:
import UIKit import ValidatorUI import ValidatorCore class ViewController: UIViewController { let emailField = UITextField() override func viewDidLoad() { super.viewDidLoad() // Add validation rules emailField.add( rule: RegexValidationRule( pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}", error: "Please enter a valid email" ) ) // Enable real-time validation emailField.validateOnInputChange(isEnabled: true) // Handle validation results emailField.validationHandler = { result in switch result { case .valid: self.updateUI(isValid: true) case .invalid(let errors): self.showErrors(errors) } } } }Use the .validation() modifier for simple field validation:
import SwiftUI import ValidatorUI import ValidatorCore struct LoginView: View { @State private var email = "" var body: some View { TextField("Email", text: $email) .validation($email, rules: [ RegexValidationRule( pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}", error: "Invalid email" ) ]) { result in if case .invalid(let errors) = result { print("Validation errors: \(errors)") } } } }Or use .validate() with a custom error view:
struct LoginView: View { @State private var password = "" var body: some View { VStack(alignment: .leading) { SecureField("Password", text: $password) .validate(item: $password, rules: [ LengthValidationRule(min: 8, error: "Too short") ]) { errors in ForEach(errors, id: \.message) { error in Text(error.message) .foregroundColor(.red) .font(.caption) } } } } }Manage multiple fields with FormFieldManager:
import Combine import SwiftUI import ValidatorUI import ValidatorCore class RegistrationForm: ObservableObject { @Published var manager = FormFieldManager() @FormField(rules: [ LengthValidationRule(min: 2, max: 50, error: "Invalid name length") ]) var firstName = "" @FormField(rules: [ LengthValidationRule(min: 2, max: 50, error: "Invalid name length") ]) var lastName = "" @FormField(rules: [ RegexValidationRule( pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}", error: "Invalid email" ) ]) var email = "" lazy var firstNameContainer = _firstName.validate(manager: manager) lazy var lastNameContainer = _lastName.validate(manager: manager) lazy var emailContainer = _email.validate(manager: manager) } struct RegistrationView: View { @StateObject private var form = RegistrationForm() @State private var isFormValid = false var body: some View { Form { Section("Personal Information") { TextField("First Name", text: $form.firstName) .validate(validationContainer: form.firstNameContainer) { errors in ErrorView(errors: errors) } TextField("Last Name", text: $form.lastName) .validate(validationContainer: form.lastNameContainer) { errors in ErrorView(errors: errors) } } Section("Contact") { TextField("Email", text: $form.email) .validate(validationContainer: form.emailContainer) { errors in ErrorView(errors: errors) } } Section { Button("Submit") { form.manager.validate() } .disabled(!isFormValid) } } .onReceive(form.manager.$isValid) { newValue in isFormValid = newValue } } private func submitForm() { print("✅ Form is valid, submitting...") } }| Validator | Description | Example |
|---|---|---|
LengthValidationRule | Validates string length (min/max) | LengthValidationRule(min: 3, max: 20, error: "Length must be 3-20 characters") |
NonEmptyValidationRule | Ensures string is not empty or blank | NonEmptyValidationRule(error: "Field is required") |
PrefixValidationRule | Validates string prefix | PrefixValidationRule(prefix: "https://", error: "URL must start with https://") |
SuffixValidationRule | Validates string suffix | SuffixValidationRule(suffix: ".com", error: "Domain must end with .com") |
RegexValidationRule | Pattern matching validation | RegexValidationRule(pattern: "^\\d{3}-\\d{4}$", error: "Invalid phone format") |
URLValidationRule | Validates URL format | URLValidationRule(error: "Please enter a valid URL") |
CreditCardValidationRule | Validates credit card numbers (Luhn algorithm) | CreditCardValidationRule(error: "Invalid card number") |
EmailValidationRule | Validates email format | EmailValidationRule(error: "Please enter a valid email") |
CharactersValidationRule | Validates that a string contains only characters from the allowed CharacterSet | CharactersValidationRule(characterSet: .letters, error: "Invalid characters") |
NilValidationRule | Validates that value is nil | NilValidationRule(error: "Value must be nil") |
PositiveNumberValidationRule | Validates that value is positive | PositiveNumberValidationRule(error: "Value must be positive") |
NoWhitespaceValidationRule | Validates that a string does not contain any whitespace characters | NoWhitespaceValidationRule(error: "Spaces are not allowed") |
ContainsValidationRule | Validates that a string contains a specific substring | ContainsValidationRule(substring: "@", error: "Must contain @") |
EqualityValidationRule | Validates that the input is equal to a given reference value | EqualityValidationRule(compareTo: password, error: "Passwords do not match") |
ComparisonValidationRule | Validates that input against a comparison constraint | ComparisonValidationRule(greaterThan: 0, error: "Must be greater than 0") |
IBANValidationRule | Validates that a string is a valid IBAN (International Bank Account Number) | IBANValidationRule(error: "Invalid IBAN") |
IPAddressValidationRule | Validates that a string is a valid IPv4 or IPv6 address | IPAddressValidationRule(version: .v4, error: ValidationError("Invalid IPv4")) |
PostalCodeValidationRule | Validates postal/ZIP codes for different countries | PostalCodeValidationRule(country: .uk, error: "Invalid post code") |
Create custom validation rules by conforming to IValidationRule:
import ValidatorCore struct EmailDomainValidationRule: IValidationRule { typealias Input = String let allowedDomains: [String] let error: IValidationError init(allowedDomains: [String], error: IValidationError) { self.allowedDomains = allowedDomains self.error = error } func validate(input: String) -> Bool { guard let domain = input.split(separator: "@").last else { return false } return allowedDomains.contains(String(domain)) } } // Usage let rule = EmailDomainValidationRule( allowedDomains: ["company.com", "company.org"], error: "Only company email addresses are allowed" )Combine multiple validators for complex validation logic:
// Define reusable validation rules let lengthRule = LengthValidationRule( min: 8, max: 128, error: "Password must be 8-128 characters" ) let uppercaseRule = RegexValidationRule( pattern: ".*[A-Z].*", error: "Must contain uppercase letter" ) let lowercaseRule = RegexValidationRule( pattern: ".*[a-z].*", error: "Must contain lowercase letter" ) let numberRule = RegexValidationRule( pattern: ".*[0-9].*", error: "Must contain number" ) let specialCharRule = RegexValidationRule( pattern: ".*[!@#$%^&*(),.?\":{}|<>].*", error: "Must contain special character" ) // UIKit: Pass all rules to your text field passwordField.add(rules: [ lengthRule, uppercaseRule, lowercaseRule, numberRule, specialCharRule ]) // SwiftUI: Use in validation modifier SecureField("Password", text: $password) .validation($password, rules: [ lengthRule, uppercaseRule, lowercaseRule, numberRule, specialCharRule ]) { result in if case .invalid(let errors) = result { self.passwordErrors = errors } }You can find usage examples in the Examples directory of the repository.
These examples demonstrate how to integrate the package, configure validation rules,
and build real-world user interfaces using ValidatorCore and ValidatorUI.
- 🐛 Found a bug? Open an issue
- 💡 Have a feature request? Open an issue
- ❓ Questions? Start a discussion
- 🔒 Security issue? Email nv3212@gmail.com
We love contributions! Please read our Contributing Guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes.
Bootstrap the development environment:
mise installThis project adheres to the Contributor Covenant Code of Conduct. By participating, you are expected to uphold this code.
Nikita Vasilev
- Email: nv3212@gmail.com
- GitHub: @ns-vasilev
Validator is released under the MIT license. See LICENSE for details.
Made with ❤️ by space-code