chunk-promise

chunk-promise is a tiny library that can be used to run a list of native promises in chunks/patches by creating a promise chain with some optional customization that gives you full control over these promises.

It supports running both Promise.all and Promise.allSettled flavors in chunks. It can be used to run Promise.allSettled in browsers that do not support it. It can be combined with async/await.

What is Promise.allSettled? see here

Why new library?

Yes, there are lots of libraries that give you some control over promises.

bluebird: This library does not use native promises, it is using its own version of promises.

p-limit: It does use native promises but it neither support Promise.allSettled nor callbacks between chunks.

Aren't native promises enough?

Well, it depends in your situation. If you want to use either native promises or async/await they are definitely doing great however both Promise.all and Promise.allSettled would run all functions in parallel with no control over how many promises to run in patches. they do not support running promises in chunks. You simply have a list of promises that run all in parallel.

Why should I use this library?

• If you want to run promises in chunks with both Promise.all and Promise.allSettled flavors where every single chunk runs (n) number of promises in parallel.

• If you want to slow down the execution by introducing sleep/timeout function between chunks.

• If you want to call a custom function after every single chunk.

• If you want to force stop the promises execution for some reason in the middle.

• If you want to use Promise.allSettled in browsers that do not support it, or in Node (only supported natively in Node starting from version 12)

All of these functionality are packed inside one small yet powerful library.

How to use

npm install chunk-promise

Available promise customizations

Option	Required?	Description	Default value
concurrent	No	Number of concurrent promises to run in a single chunk	Infinity
sleepMs	No	Sleep function in milliseconds between chunks	undefined
callback	No	Callback async function to be called after every single chunk. It exposes 3 params: - chunkResults: the current chunk value. - chunkIndex: the current chunk index. - allResults: the results of the promises so far.	undefined
promiseFlavor	No	Choose between Promise.all and Promise.allSettled	Promise.all
logMe	No	Log what will be running	false

Examples

1. Run list of promises in chunks using Promise.all

const { chunkPromise, PromiseFlavor } = require('chunk-promise');

const promiseArr = [
  () => Promise.resolve(1),
  () => Promise.reject(2),
  () => Promise.resolve(3),
  () => Promise.reject(4),
  () => Promise.resolve(5)
];

chunkPromise(promiseArr, {
  concurrent: 2,
  promiseFlavor: PromiseFlavor.PromiseAll
})
  .then(res => {})
  .catch(err => {});

2. Run list of promises in chunks using Promise.allSettled

const { chunkPromise, PromiseFlavor } = require('chunk-promise');

const promiseArr = [
  () => Promise.resolve(1),
  () => Promise.reject(2),
  () => Promise.resolve(3),
  () => Promise.reject(4),
  () => Promise.resolve(5)
];

chunkPromise(promiseArr, {
  concurrent: 2,
  promiseFlavor: PromiseFlavor.PromiseAllSettled
}).then(res => {});

3. Run list of promises in chunks using Promise.all and slow down by sleeping for 2 seconds between chunks.

const { chunkPromise, PromiseFlavor } = require('chunk-promise');

const promiseArr = [
  () => Promise.resolve(1),
  () => Promise.reject(2),
  () => Promise.resolve(3),
  () => Promise.reject(4),
  () => Promise.resolve(5)
];

chunkPromise(promiseArr, {
  concurrent: 2,
  promiseFlavor: PromiseFlavor.PromiseAll,
  sleepMs: 2000
})
  .then(res => {})
  .catch(err => {});

4. Run list of promises in chunks using Promise.allSettled and run a callback function after every chunk.

const { chunkPromise, PromiseFlavor } = require('chunk-promise');

const promiseArr = [
  () => Promise.reject(1),
  () => Promise.reject(2),
  () => Promise.resolve(3),
  () => Promise.reject(4),
  () => Promise.resolve(5)
];

chunkPromise(promiseArr, {
  concurrent: 2,
  promiseFlavor: PromiseFlavor.PromiseAllSettled,
  callback: async (chunkResults, index, allResults) => {
    if (chunkResults.some(p => p.status === 'fulfilled')) {
      console.log(`chunk (${index}): has success results`);
    } else {
      console.log(`chunk (${index}): has no success results`);
    }
  }
}).then(res => {});

5. Run list of promises in chunks using Promise.all and run a callback function after every chunk and force stop the promise chain.

const {
  chunkPromise,
  PromiseFlavor,
  ChunkPromiseCallbackForceStopError
} = require('chunk-promise');

const promiseArr = [
  () => Promise.resolve(1),
  () => Promise.resolve(2),
  () => Promise.resolve(3),
  () => Promise.resolve(4),
  () => Promise.resolve(5)
];

chunkPromise(promiseArr, {
  concurrent: 2,
  promiseFlavor: PromiseFlavor.PromiseAll,
  callback: async (chunkResults, index, allResults) => {
    console.log(`chunk (${index}): has success results`);
    if (index === 1) {
      throw new ChunkPromiseCallbackForceStopError(
        `Callback force stop at chunk index ${index}`
      );
    }
  }
})
  .then(res => {})
  .catch(err => {
    if (err instanceof ChunkPromiseCallbackForceStopError) {
      console.log('Force stop');
    } else {
      console.log('failed');
    }
  });

Any suggestions?

Please do not hesitate to report any issue/improvement if you want to add more options/customizations to this library.