@chalker/queue
v1.0.0
Published
A trivial queue / mutex lock implementation
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@chalker/queue
A trivial Queue / Lock implementation that I used in my personal projects.
Example: https://github.com/nodejs/Gzemnid/blob/main/src/queue.js
Queue
Usage:
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()
}
Lock
new Lock()
is just an alias to new Queue(1)
, which can be used
import { Queue } from '@chalker/queue'
const lock = new Lock()
async function run() {
await lock.claim()
// do async stuff with maximum concurrency = 1
lock.release()
}
Full example
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: ${++concurrency}`)
await new Promise(resolve => setTimeout(resolve, 1))
console.log(`End #${x}, concurrency: ${concurrency--}`)
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