A trivial queue / mutex lock implementation
npm install @chalker/queueA trivial Queue / Lock implementation that I used in my personal projects.
Example: https://github.com/nodejs/Gzemnid/blob/main/src/queue.js
Usage:
``js
import { Queue } from '@chalker/queue'
const queue = new Queue(10) // concurrency
async function run() {
await queue.claim()
// do async stuff with controlled maximum concurrency
queue.release()
}
`
new Lock() is just an alias to new Queue(1), which can be used
`js
import { Queue } from '@chalker/queue'
const lock = new Lock()
async function run() {
await lock.claim()
// do async stuff with maximum concurrency = 1
lock.release()
}
`
`js
import { Queue } from '@chalker/queue'
const queue = new Queue(3)
let concurrency = 0 // Just for testing purposes
async function run(x) {
await queue.claim()
console.log(Start #${x}, concurrency: ${++concurrency})End #${x}, concurrency: ${concurrency--}
await new Promise(resolve => setTimeout(resolve, 1))
console.log()
queue.release()
}
const args = new Array(6).fill(0).map((_, i) => i + 1)
await Promise.all(args.map(run))
`
Output:
`
Start #1, concurrency: 1
Start #2, concurrency: 2
Start #3, concurrency: 3
End #1, concurrency: 3
Start #4, concurrency: 3
End #2, concurrency: 3
Start #5, concurrency: 3
End #3, concurrency: 3
Start #6, concurrency: 3
End #4, concurrency: 3
End #5, concurrency: 2
End #6, concurrency: 1