ValSan

ValSan provides a clean, type-safe way to validate and transform data and input.

Features

• Type-safe - Full TypeScript support with generics
• Async-first - Built for I/O operations (supports DB checks, API calls)
• Structured errors - Machine-readable error codes with context
• Type transformation - Convert types during sanitization
• Configurable - Pass options to customize validator behavior
• Extensible - Create your own ValSans
• Composable - Build validation/sanitization pipelines

Install

npm install valsan

Quick Start

What is a ValSan?

A ValSan is a Validator + Sanitizer. It checks input data, and returns it in a clean and consistent type/format.

Example - Object Validation & Sanitization

import {
    ObjectValSan,
    LengthValidator,
    LowercaseSanitizer,
    TrimSanitizer,
    EmailValidator,
    ComposedValSan
} from 'valsan';

const usernameValSan = new ComposedValSan<string, string>([
    new TrimSanitizer(),
    new LengthValidator({ minLength: 5, maxLength: 10 }),
    new LowercaseSanitizer(),
]);

// Create an object validator
const validator = new ObjectValSan({
  schema: {
    username: usernameValSan,
    optionalUsername: usernameValSan.copy({ isOptional: true }),
    email: new EmailValidator(),
  }
});

// Validate & sanitize input data
const result = await validator.run({
    username: 'alice',
    email: 'alice@example.com'
});

if (result.success) {
    console.log('Sanitized:', result.data);
}
else {
    console.error('Validation errors:', result.errors);
}

// ObjectValSan can also be nested for complex structures:
const addressSchema = new ObjectValSan({
  schema: {
    street: new TrimSanitizer(),
    city: new TrimSanitizer(),
  }
});

const userValidator = new ObjectValSan({
  schema: {
    username: usernameValSan,
    email: new EmailValidator(),
    address: addressSchema, // Nested object
  }
});

Note: ObjectSanitizer is now deprecated in favor of ObjectValSan. ObjectSanitizer will be removed in a future major version.

Using Built-in Primitives

ValSan includes ready-to-use primitive validators for common validation tasks:

import { RangeValidator } from 'valsan';

// Number validation
const range = new RangeValidator({ min: 0, max: 100 });
const result = await range.run(150);
console.log(result.success); // false - out of range

Primitives Library

Compose your own validators from built-in primitives:

Primitives Reference

More

• Custom Validators
• Composed Validators
• Options
• Rules

Contributing & Development

See contributing.md for information on how to develop or contribute to this project!