aceink

Useful async tools.

• createLock
  • a simple counting sempahore
• createDeferred
  • simple deferred promise
• q
  • a concurrent work queue
  • supports pause(), start(), clear(), and onEmpty() for queue control
• each, map
  • optionally concurrent iteration functions
• timeout and signal options
  • bound hung queue, each, and map work
• gowait
  • convert a promise or promise returning function to [error,result] tuples
• delay
  • delay ms, optionally resolve an argument
• noop, identity, once
  • Other useful language functions

Get it on npm: npm install aceink

See the generated documentation here

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Example (queue)

import { q } from 'aceink'

const { ready, add, empty } = q(10)

function fetchQux(bar) {
  return fetch(`https://example.com/${bar}`)
}

for (const foo of Array(100).keys()) {
  await ready()
  add(fetchQux, foo)
}
return empty()

Queue tasks can also be time-bounded or aborted while waiting or running:

import { AbortError, q } from 'aceink'

const queue = q(2, { timeout: 5000 })
const controller = new AbortController()

try {
  const work = queue.add(() => fetch('https://example.com'), undefined, { signal: controller.signal })

  controller.abort()
  await work
} catch (error) {
  if (!(error instanceof AbortError)) throw error
}

Queues can also be paused, resumed, or cleared without affecting work that is already running:

import { QueueClearedError, q } from 'aceink'

const queue = q(2)

queue.pause()
const work = queue.add(async () => 'value')

queue.start()
await work

const queued = queue.add(async () => 'queued later')
queue.clear()

try {
  await queued
} catch (error) {
  if (!(error instanceof QueueClearedError)) throw error
}

await queue.onEmpty() // queued work has been dequeued; running work may still settle

Example (gowait)

import { gowait, delay } from 'aceink'

const [err, value] = await gowait(delay(100, 42))
console.log(value) //42