dreadlocks2

Dread-free locks that drive consistency.

Summary

• Create and use keys to identify objects:
  • let key1 = hash(whatever)
  • let key2 = {whatever: 'whatever'}
  • let key3 = Symbol('whatever')
• Create key sets for keys involved in each task:
  • const keySet = [key1, key2, key3]
• Lock these key sets
  • Dread.lock(keySet).then(task)
• Release these key sets once you're done.
  • Dread.release(keySet)

Perks

• Respects FIFO (first-in-first-out) flow:
  • Iterates on queue on every release.
• Uses Map so you can use anything as a key.
  • Map has higher limits than Object.

Use Cases:

• Database consistency & transactions.
• Ensuring order in execution of tasks that wish to modify possibly similar objects or entities.

Changelog

• v2.x
  • Removed setInterval, smarter locking mechanism.
• v1.x
  • Uses setInterval, has immediate-locking mechanism.

class Dreadlock

• constructor ()
• method lock (items)
  • items array of keys to lock
  • RETURNS Promise, resolves on lock success
• method release (items)
  • items array of keys to release
  • RETURNS Promise, resolves on release success
• property size
  • RETURNS current size of instance Map
• property length
  • RETURNS current size of instance Array queue

Usage:

• Install:

npm install dreadlocks2 --save
yarn add dreadlocks2

const Dreadlock = require('dreadlocks2');

• Create instance:

const Dread = new Dreadlock();

• Lock your keys anywhere in your code:

const keySet1 = ['key1', 'key2', 'key3'];
Dread.lock(keySet1)
  .then(() => {
    console.log('Working with keySet1.');
    // Use your keySet1 keys here
    console.log('Done with keySet1.');
    return Dread.release(keySet1);
  })
  .then(() => {
    console.log('keySet1 released.');
  });

const keySet2 = ['key1', 'key4', 'key5'];
Dread.lock(keySet2)
  .then(() => {
    console.log('Working with keySet2.');
    // Use your keySet2 keys here
    console.log('Done with keySet2.');
    return Dread.release(keySet2);
  })
  .then(() => {
    console.log('keySet2 released.');
  });

• See the magic:

Working with keySet1.
Done with keySet1.
keySet1 released.
Working with keySet2.
Done with keySet2.
keySet2 released.

License

Attribution 4.0 International (CC BY 4.0)

• https://creativecommons.org/licenses/by/4.0/
• https://creativecommons.org/licenses/by/4.0/legalcode.txt