rwmutex-ts

🧵 Reader-writer mutex for TypeScript / ESM with timeout support and lock priority

✨ Features

• ✅ Asynchronous read-write mutex implementation
• ⏱️ Supports timeout for lock acquisition
• ⚖️ Prioritizes writers over readers to avoid starvation
• 🧪 Tested with Vitest
• 📦 ESM-native and typed (.d.ts)

📦 Installation

npm install rwmutex-ts

🔧 Usage

import { RWMutex } from 'rwmutex-ts';

const mutex = new RWMutex();

// Reader section
await mutex.withReadLock(async () => {
  // Shared resource access
});

// Writer section
await mutex.withWriteLock(async () => {
  // Exclusive access
});

⏱️ Lock Timeout Example

You can pass a timeout (in milliseconds) to abort if the lock can't be acquired:

try {
  await mutex.withWriteLock(async () => {
    // critical section
  }, 200); // try for max 200ms
} catch (err) {
  console.error('Write lock timeout:', err);
}

🧪 Test

npm run test

📘 API

withReadLock(fn: () => Promise<T>, timeoutMs?: number): Promise<T>

Executes fn under a read lock. Fails if the lock cannot be acquired within the timeout.

withWriteLock(fn: () => Promise<T>, timeoutMs?: number): Promise<T>

Executes fn under a write lock. Timeout behaves the same.

📄 License

MIT © 2025 Your Name

🛠 Example Projects

• 🔐 Locking shared config access in SSR apps
• 📁 Concurrent file readers
• 🧵 Concurrency control in worker pools

PRs and issues welcome!