@yazouv/form-validator

A lightweight, TypeScript-based form validation library with a simple and intuitive API.

Features

• 🚀 Lightweight - Minimal dependencies, small bundle size
• 📝 TypeScript - Full TypeScript support with type definitions
• 🔧 Simple API - Easy to use pipe-based rule syntax
• ⚡ Fast - Efficient validation with early returns
• 🎯 Flexible - Combine multiple validation rules easily
• 🔌 Extensible - Built-in rules cover most common use cases

Installation

npm install @yazouv/form-validator

Quick Start

import { validate } from "@yazouv/form-validator";

// Define your data
const formData = {
  name: "John Doe",
  email: "[email protected]",
  age: "25",
};

// Define validation rules
const rules = {
  name: "required",
  email: "required|email",
  age: "required|number|min:18",
};

// Validate
const result = validate(formData, rules);

if (result.valid) {
  console.log("✅ Form is valid!");
} else {
  console.log("❌ Validation errors:", result.errors);
}

Available Validation Rules

Basic Rules

| Rule | Description | Example | | ---------- | ----------------------- | ------------ | | required | Field must not be empty | "required" | | email | Valid email format | "email" | | number | Must be a valid number | "number" | | link | Valid URL format | "link" |

Numeric Rules

| Rule | Description | Example | | -------------- | ------------- | ------------------ | | min:X | Minimum value | "min:18" | | max:X | Maximum value | "max:65" | | min:X\|max:Y | Value range | "min:18\|max:65" |

String Rules

| Rule | Description | Example | | --------------- | ------------------------------------------------- | --------------------- | | slug | URL-friendly format (lowercase, numbers, hyphens) | "slug" | | regex:pattern | Custom regex pattern | "regex:^[A-Z]{2,}$" |

Combining Rules

Use the pipe (|) character to combine multiple rules:

const rules = {
  username: "required|slug",
  email: "required|email",
  age: "required|number|min:18|max:99",
  website: "link", // Optional field
  password: "required|regex:^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{8,}$",
};

Examples

Basic Form Validation

import { validate } from "@yazouv/form-validator";

const userData = {
  firstName: "John",
  lastName: "Doe",
  email: "[email protected]",
  age: "28",
};

const rules = {
  firstName: "required",
  lastName: "required",
  email: "required|email",
  age: "required|number|min:18",
};

const result = validate(userData, rules);
// { valid: true, errors: {} }

Handling Validation Errors

const invalidData = {
  firstName: "",
  email: "invalid-email",
  age: "15",
};

const result = validate(invalidData, rules);

if (!result.valid) {
  // Handle each field's errors
  Object.entries(result.errors).forEach(([field, errors]) => {
    console.log(`${field}: ${errors.join(", ")}`);
  });
}

// Output:
// firstName: This field is required
// email: Invalid email format
// age: Must be at least 18

Advanced Examples

User Registration Form

const registrationData = {
  username: "john-doe",
  email: "[email protected]",
  password: "MySecurePass123",
  age: "25",
  website: "https://johndoe.com",
};

const registrationRules = {
  username: "required|slug",
  email: "required|email",
  password: "required|regex:^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{8,}$",
  age: "required|number|min:18",
  website: "link", // Optional
};

const result = validate(registrationData, registrationRules);

E-commerce Product Form

const productData = {
  name: "Gaming Laptop",
  price: "999.99",
  category: "electronics",
  description: "High-performance gaming laptop",
};

const productRules = {
  name: "required",
  price: "required|number|min:0",
  category: "required|slug",
  description: "required|max:500",
};

Contact Form with Phone Validation

const contactData = {
  name: "Jane Smith",
  email: "[email protected]",
  phone: "+1234567890",
  message: "Hello, I'm interested in your services.",
};

const contactRules = {
  name: "required",
  email: "required|email",
  phone: "regex:^\\+?[1-9]\\d{1,14}$",
  message: "required|min:10|max:1000",
};

API Reference

validate(data, rules)

Validates an object against a set of rules.

Parameters:

• data (object): The data object to validate
• rules (object): Object defining validation rules for each field

Returns:

• { valid: boolean, errors: object } - Validation result

Example:

const result = validate(
  { email: "[email protected]" },
  { email: "required|email" }
);
// { valid: true, errors: {} }

Error Messages

The library provides clear, user-friendly error messages:

• required: "This field is required"
• email: "Invalid email format"
• number: "Must be a number"
• link: "This field must be a valid URL"
• min:X: "Must be at least X"
• max:X: "Must be at most X"
• slug: "Invalid format"
• regex: "Invalid format"

TypeScript Support

Full TypeScript support with proper type definitions:

interface ValidationResult {
  valid: boolean;
  errors: Record<string, string[]>;
}

function validate(
  data: Record<string, any>,
  rules: Record<string, string>
): ValidationResult;

Contributing

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

License

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

Support

If you find this package useful, please consider giving it a ⭐ on GitHub!

For issues and feature requests, please use the GitHub Issues page.