@variablesoftware/vs-brand-utils 🏷️🧩🛡️

Nominal (branded) TypeScript types & helpers for safe opaque types.

🏷️🧩🛡️ Type-safe branding for primitives and objects in TypeScript.

Usage Guide

See the Usage Guide for practical examples and patterns.

API Reference

See the API Reference for a summary of all exports and detailed documentation.

🔧 Installation

pnpm add @variablesoftware/vs-brand-utils

🚀 Usage

import {
  Brand,
  brand,
  isBrand,
  assertBrand,
  unbrand,
  createBrand,
  brandArray,
  unbrandArray,
  brandMany
} from "@variablesoftware/vs-brand-utils";

// Define a branded type
export type UserId = Brand<"UserId", string>;

// Brand a value
const id = brand<"UserId", string>("UserId", "abc123");

// Type-safe: cannot assign UserId to string or vice versa
// const s: string = id; // Type error
// const id2: UserId = 'plainstring'; // Type error

// Type guard
if (isBrand("UserId", id)) {
  // id is UserId here
}

// Assert
assertBrand("UserId", id);

// Unbrand
const raw: string = unbrand("UserId", id);

// Brand an array
const brandedArr = brandArray("UserId", ["a", "b"]);

// Unbrand an array
const arr: string[] = unbrandArray("UserId", brandedArr);

// Brand many values
const many = brandMany("UserId", "a", "b");

// Factory for a specific brand
const TenantId = createBrand<"TenantId", string>("TenantId");
const tid = TenantId.brand("t-123");

✨ Features

• 🏷️ Nominal/opaque types for primitives and objects
• 🧩 Type-safe branding and unbranding helpers
• 🛡️ Compile-time enforcement: prevents accidental mixing of branded and unbranded types
• Array helpers for batch branding/unbranding
• Factory for reusable brand helpers
• Zero runtime cost: all checks are type-level
• 100% test and code coverage (see tests/unit/ for split test suites)
• Edge-case and runtime safety for all helpers

🎯 Goals

• Prevent accidental mixing of IDs, tokens, and other primitives
• Enable safe domain modeling with TypeScript
• No runtime overhead or dependencies
• Simple, composable API
• Fully documented and tested

🧪 Test Coverage

Tested using vitest with coverage for:

• Branding and unbranding
• Type guards and assertions
• Compile-time type errors
• Array helpers
• Edge cases and runtime behaviors

Test suites are organized by concern:

• runtime-branding.test.ts
• compile-type-errors.test.ts
• helpers-and-factory.test.ts
• edge-cases.test.ts
• missing-marker-edge-cases.test.ts

Run tests:

pnpm test

📦 Modular Structure (vNext)

As of May 2025, the codebase is split into focused modules for maintainability and tree-shaking:

• core – core types and internal symbols
• brand – branding helpers (brand, brandArray, brandMany)
• typeguards – type guard helpers (isBrand)
• assert – assertion helpers (assertBrand)
• unbrand – unbranding helpers (unbrand, unbrandArray)
• factory – the createBrand factory for a bundled API

You can import everything from the main entry point:

import { brand, isBrand, assertBrand, unbrand, createBrand } from "@variablesoftware/vs-brand-utils";

Or, for advanced usage and smaller bundles, import only what you need:

import { brand } from "@variablesoftware/vs-brand-utils/brand";
import { isBrand } from "@variablesoftware/vs-brand-utils/typeguards";

All helpers are still available via the main package import for convenience.

🧪 Test Coverage & Code Structure

• All helpers and edge cases are tested for 100% coverage.
• See src/ for the modular implementation.
• See tests/unit/ for split test suites by concern.

🚧 Status

This package is under active development and not yet stable.

Once stable, it will be published as:

"@variablesoftware/vs-brand-utils": "^0.8.0"

📄 License

MIT © Rob Friedman / Variable Software

Built with ❤️ by @variablesoftware
Thank you for downloading and using this project. Pull requests are warmly welcomed!

🌐 Inclusive & Accessible Design

• Naming, logging, error messages, and tests avoid cultural or ableist bias
• Avoids assumptions about input/output formats or encodings
• Designed for clarity, predictability, and parity with TypeScript best practices
• Works well in diverse, multilingual, and inclusive developer environments