duckhawk

Native Promise based implementations of bluebird utilities with zero dependencies and miniature bundle size.

Install

Instructions on jsr: https://jsr.io/@tyler/duckhawk

Docs

allChunked

This helper is unique to duckhawk. We support easily running a large list of promises n at a time. This is useful for avoiding issues like running out of memory in Promise.all, avoiding being throttled with too many requests, and avoiding concurrent writes to the same resource.

import { allChunked } from "duckhawk";

const result = await allChunked(
  [Promise.resolve(1), Promise.resolve(2), Promise.resolve(3)],
  2
);

console.log(result); // [1, 2, 3]

map

Bluebird equivalent: http://bluebirdjs.com/docs/api/promise.map.html

This awaits each promise in parallel and passes the result to the iterator. The result of the iterator is returned as an array.

import { map } from "duckhawk";

const result = await map([1, 2, 3], (item) => Promise.resolve(item + 1));

concurrency can be passed to limit the number of promises to run a specific number at a time. Otherwise, we will run with Promise.all.

import { map } from "duckhawk";

const result = await map([1, 2, 3], (item) => Promise.resolve(item + 1), {
  concurrency: 2,
});

mapSeries

Bluebird equivalent: http://bluebirdjs.com/docs/api/promise.mapseries.html

This awaits each promise in series and passes the result to the iterator. The result of the iterator is returned as an array.

import { mapSeries } from "duckhawk";

const result = await mapSeries([1, 2, 3], (item) => Promise.resolve(item + 1));

console.log(result); // [2, 3, 4]

props

Bluebird equivalent: http://bluebirdjs.com/docs/api/promise.props.html

We implement props with Promise.allSettled to give the same easy api for resolving a list of promises as key/value pairs.

import { props } from "duckhawk";

const result = await props({
  one: fetch("https://pokeapi.co/api/v2/pokemon/1").then((res) => res.json()),
  two: fetch("https://pokeapi.co/api/v2/pokemon/2").then((res) => res.json()),
  three: fetch("https://pokeapi.co/api/v2/pokemon/3").then((res) => res.json()),
});

reduce

Bluebird equivalent: http://bluebirdjs.com/docs/api/promise.reduce.html

This awaits each promise in series and passes the result to the iterator. The final accumulator is returned if all promises resolve successfully.

import { reduce } from "duckhawk";

const result = await reduce(
  [1, 2, 3],
  (acc, item) => Promise.resolve(acc + item),
  0
);

console.log(result); // 6

Notes

We do not plan to achieve 100% parity with bluebird. If you find this library useful and want a feature added, please open an issue :).

The Why

This is for moving away from bluebird in favor of native Promises and async/await. Some of the bluebird methods are useful and easy to re-implement in native Promises, so we've added the ones we need here.

If you're starting a project from scratch, I'd encourage writing your own promise utils. Feel free to copy-paste any of the ones from here as examples! But, the main motivator for using this as a library is for an easy off-ramp for large projects that use bluebird in many places and want a super simple refactor path.

If you want to replace bluebird with a zero dependency library, this should be a great fit!