Ctrovalidate

The lightweight, declarative, and accessible form validation library for modern web apps.

Documentation • Live Demo • API Reference • Contributing

🎯 Why Ctrovalidate?

Ctrovalidate is a zero-dependency, TypeScript-native form validation library that bridges the gap between raw DOM power and framework-ready APIs. It embraces a declarative, HTML-first approach, allowing you to define validation rules directly in your markup using data attributes.

✨ Key Features

• 🎨 HTML-First Philosophy - Validation rules live in your markup, not scattered across JavaScript
• ♿ Accessibility by Default - Automatic ARIA management (aria-invalid, aria-describedby)
• ⚡ Async Validation - Built-in support for Promise-based rules with abort controllers
• 🔗 Field Dependencies - Conditional validation based on other field states
• 🎭 Framework Agnostic - Works with React, Vue, Next.js, Alpine.js, HTMX, or vanilla JS
• 📦 Micro-Weight - <5KB gzipped, zero dependencies
• 🔒 TypeScript Native - Full type safety with comprehensive .d.ts files
• 🧪 98% Test Coverage - Production-ready reliability
• 🎮 Rich API - 9 public methods for complete control
• 🌐 21 Built-in Rules - Common, format, and numeric validation out of the box

📦 Installation

# npm
npm install ctrovalidate

# yarn
yarn add ctrovalidate

# pnpm
pnpm add ctrovalidate

🚀 Quick Start

1. The Markup (HTML-First)

<form id="registrationForm" novalidate>
  <div class="form-group">
    <label for="email">Email Address</label>
    <input
      type="email"
      name="email"
      id="email"
      data-ctrovalidate-rules="required|email"
      placeholder="[email protected]"
    />
    <div class="error-message"></div>
  </div>

  <div class="form-group">
    <label for="password">Password</label>
    <input
      type="password"
      name="password"
      id="password"
      data-ctrovalidate-rules="required|strongPassword"
    />
    <div class="error-message"></div>
  </div>

  <button type="submit">Register</button>
</form>

2. The Implementation

import { Ctrovalidate } from 'ctrovalidate';

// Initialize validator
const validator = new Ctrovalidate(
  document.querySelector('#registrationForm'),
  {
    realTime: true, // Validate on blur/input
    errorClass: 'is-invalid', // CSS class for invalid fields
    pendingClass: 'is-validating', // CSS class during async validation
  }
);

// Validate on submit
form.addEventListener('submit', async (e) => {
  e.preventDefault();

  const isValid = await validator.validate();

  if (isValid) {
    // Submit to your API
    const formData = new FormData(form);
    await fetch('/api/register', {
      method: 'POST',
      body: formData,
    });
  }
});

📋 Built-in Validation Rules (21 Total)

Common Rules

• required - Field must have a value
• email - Valid email format
• minLength:n - Minimum character length
• maxLength:n - Maximum character length
• exactLength:n - Exact character length
• sameAs:fieldName - Must match another field

Format Rules

• alpha - Only alphabetic characters
• alphaNum - Alphanumeric characters only
• alphaDash - Alphanumeric with dashes/underscores
• url - Valid URL format
• phone - Valid phone number
• creditCard - Valid credit card (Luhn algorithm)
• strongPassword - Strong password requirements
• json - Valid JSON string
• ipAddress - Valid IPv4 or IPv6 address

Numeric Rules

• numeric - Any numeric value
• integer - Integer values only
• decimal - Decimal/float values
• min:n - Minimum numeric value
• max:n - Maximum numeric value
• between:min,max - Value within range

🎮 Public API Methods

// Validation
await validator.validate()        // Validate entire form

// Field Management
validator.addField(element)       // Add field dynamically
validator.removeField(element)    // Remove field dynamically
validator.refresh()               // Re-discover fields after DOM changes

// State Inspection
validator.isDirty('fieldName')    // Check if field was touched
validator.getError('fieldName')   // Get current error message

// Lifecycle
validator.reset()                 // Reset all validation states
validator.destroy()               // Clean up validator instance

// Static Methods (Global)
Ctrovalidate.addRule(name, logic, message?)        // Add custom rule
Ctrovalidate.addAsyncRule(name, logic, message?)   // Add async rule
Ctrovalidate.setCustomMessages(messages)           // Override messages

🔧 Advanced Features

Async Validation

// Register async rule (e.g., check username availability)
Ctrovalidate.addAsyncRule(
  'usernameAvailable',
  async (value, params, element, signal) => {
    const response = await fetch(`/api/check-username?username=${value}`, {
      signal, // Abort if user types again
    });
    const data = await response.json();
    return data.available;
  },
  'This username is already taken.'
);

<input name="username" data-ctrovalidate-rules="required|usernameAvailable" />

Conditional Validation (Dependencies)

<!-- Controller field -->
<select name="contact_method">
  <option value="email">Email</option>
  <option value="phone">Phone</option>
</select>

<!-- Validates only if contact_method = "email" -->
<input
  name="email"
  data-ctrovalidate-rules="required|email"
  data-ctrovalidate-if="contact_method:value:email"
/>

<!-- Validates only if contact_method = "phone" -->
<input
  name="phone"
  data-ctrovalidate-rules="required|phone"
  data-ctrovalidate-if="contact_method:value:phone"
/>

Custom Rules

// Add custom synchronous rule
Ctrovalidate.addRule(
  'isCompanyEmail',
  (value) => value.endsWith('@company.com'),
  'Please use your company email address.'
);

Custom Messages

// Override default error messages
Ctrovalidate.setCustomMessages({
  required: 'This field cannot be empty!',
  email: 'Please enter a valid email address.',
  minLength: 'Please enter at least {0} characters.',
});

Dynamic Forms

// Add field programmatically
const newInput = document.createElement('input');
newInput.name = 'additional_email';
newInput.setAttribute('data-ctrovalidate-rules', 'required|email');
form.appendChild(newInput);
validator.addField(newInput);

// Remove field
validator.removeField(newInput);
newInput.remove();

🌐 Framework Integration

Ctrovalidate works seamlessly with all major frameworks:

| Framework | Demo | Documentation | | --------------- | --------------------------------------------- | -------------------------------------------------------------------------------------------- | | Vanilla JS | demo-vanilla-js | Getting Started | | React 18+ | demo-react | React Integration | | Next.js 15+ | demo-nextjs | Next.js Integration | | Vue 3 | demo-vue | Vue Integration | | Alpine.js | demo-alpine | Alpine.js Integration | | HTMX | - | HTMX Best Practices |

🎓 Complete Feature Showcase

Check out our comprehensive demo that demonstrates every single feature:

• ✅ All 21 validation rules in real-world scenarios
• ✅ All 9 API methods with interactive controls
• ✅ Async validation with abort controllers
• ✅ Field dependencies (conditional validation)
• ✅ Custom rules and messages
• ✅ Dynamic field management
• ✅ State inspection panel
• ✅ Production-ready code with detailed comments

📖 Documentation

• 📚 Full Documentation
• 🚀 Getting Started Guide
• 🔌 API Reference
• 🎨 Framework Integrations
• 📋 Complete Feature List

🧪 Development

# Install dependencies
npm install

# Run tests
npm test

# Run tests with coverage
npm run test:coverage

# Build library
npm run build

# Run documentation site locally
npm run docs:dev

# Lint code
npm run lint

# Format code
npm run format:fix

📊 Project Stats

• Bundle Size: <5KB gzipped
• Dependencies: Zero
• Test Coverage: 98.34% statements, 94.96% branches
• TypeScript: Full support with .d.ts files
• Module Formats: ESM + UMD
• Browser Support: Modern browsers (ES2020+)
• Node.js: >=18.0.0

🤝 Contributing

We welcome contributions! Please see our Contributing Guide for details.

Development Workflow

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes with tests
4. Run npm run lint and npm test
5. Commit using Conventional Commits
6. Push and create a Pull Request

📄 License

MIT © Ctrotech

🙏 Acknowledgments

• Built with ❤️ for the industrial web
• Inspired by modern form validation best practices
• Powered by Vite, Vitest, and TypeScript

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Made with ❤️ by Ctrotech • Report Bug • Request Feature