mutexify

mutexify

Bike shed mutex lock implementation in node.js

npm install mutexify

Hasn't this been done before? Yes, but the specific semantics of this made some of my code simpler.

Usage

var mutexify = require('mutexify')
var lock = mutexify()

lock(function(release) {
  console.log('i am now locked')
  setTimeout(function() {
    release()
  }, 1000)
})

lock(function(release) {
  console.log('1 second later')
  release()
})

A common pattern is to call a callback after you release the lock. To do this in a one-liner pass the callback and the value to release(cb, err, value)

var write = function(data, cb) {
  lock(function(release) {
    fs.writeFile('locked-file.txt', data, release.bind(null, cb))
  })
}

mutexify guarantees that the order that a mutex was requested in is the order that access will be given.

You can read the lock's current state on the lock.locked property.

Usage with promises

mutexify provides a Promise-based alternative.

const mutexify = require('mutexify/promise')

;(async () => {
  var lock = mutexify()

  var release = await lock()
  console.log('i am now locked')
  setTimeout(function () {
    release()
  }, 1000)

  release = await lock()
  console.log('1 second later')
  release()
})()

License

MIT

Similar packages

Other packages similar to mutexify

async-mutex

The async-mutex package provides a similar functionality to mutexify, offering mutex and read-write lock implementations. It supports promises, making it more suitable for modern asynchronous JavaScript code compared to mutexify, which uses callbacks.

semaphore-async-await

This package offers semaphore and mutex implementations that work with async/await syntax, providing a more modern and readable approach to handling concurrency in Node.js applications compared to the callback-based approach of mutexify.