mcollina/fastp

Promise utilities

fastp

Fast promise utilities

Install

npm i fastp

API

p.limit(concurrency=1)

Limit the number of promises resolved concurrently. Offers the same API of p-limit

import p from 'fastp'
import { settimeout as sleep } from 'node:timers/promises'
const limit = p.limit(2);

const result1 = await Promise.all([
	limit(() => sleep(300, 'foo')),
	limit(() => sleep(200, 'bar')),
	limit(() => sleep(100, 'baz'))
]);
console.log(result1)
// [ 'foo', 'bar', 'baz' ]

const result2 = await Promise.race([
	limit(() => sleep(300, 'foo')),
	limit(() => sleep(200, 'bar')),
	limit(() => sleep(100, 'baz'))
]);
console.log(result2)
// 'bar'

It's over 3x faster than p-limit

╔══════════════╤═════════╤═════════════════╤═══════════╗
║ Slower tests │ Samples │          Result │ Tolerance ║
╟──────────────┼─────────┼─────────────────┼───────────╢
║ pLimit       │   10000 │ 24994.77 op/sec │  ± 3.08 % ║
╟──────────────┼─────────┼─────────────────┼───────────╢
║ Fastest test │ Samples │          Result │ Tolerance ║
╟──────────────┼─────────┼─────────────────┼───────────╢
║ fastp.limit  │   10000 │ 91958.28 op/sec │  ± 5.76 % ║
╚══════════════╧═════════╧═════════════════╧═══════════╝

License

MIT