mortice

Example

import mortice from 'mortice'
import delay from 'delay'

// the lock name & options objects are both optional
const mutex = mortice()

Promise.all([
  (async () => {
    const release = await mutex.readLock()

    try {
      console.info('read 1')
    } finally {
      release()
    }
  })(),
  (async () => {
    const release = await mutex.readLock()

    try {
      console.info('read 2')
    } finally {
      release()
    }
  })(),
  (async () => {
    const release = await mutex.writeLock()

    try {
      await delay(1000)

      console.info('write 1')
    } finally {
      release()
    }
  })(),
  (async () => {
    const release = await mutex.readLock()

    try {
      console.info('read 3')
    } finally {
      release()
    }
  })()
])
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read 1
read 2
<small pause>
write 1
read 3

Clean up

Mutexes are stored globally reference by name, this is so you can obtain the same lock from different contexts, including workers.

When a mutex is no longer required, the .finalize function should be called to remove any internal references to it.

import mortice from 'mortice'

const mutex = mortice()

// ...some time later

mutex.finalize()
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Auto clean up

If your app generates a lot of short-lived mutexes and you want to clean them up after the last lock has been released, pass the autoFinalize option to mortice in the owning context:

import mortice from 'mortice'

const mutex = mortice({
  autoFinalize: true
})

const release = await mutex.readLock()
// ...some time later

release()

// mutex will be freed soon after
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React native support

This module should run on react native but it only supports single-process concurrency as it's not clear to the author (disclaimer - not a react native dev) what the officially supported process concurrency model is.

Please open an issue if this is a feature you would like to see added.