@philiprehberger/promise-pool

Concurrent promise execution with configurable pool size

Installation

npm install @philiprehberger/promise-pool

Usage

Batch Execution

import { promisePool } from '@philiprehberger/promise-pool';

const tasks = urls.map(url => () => fetch(url).then(r => r.json()));

const { results, errors } = await promisePool(tasks, {
  concurrency: 5,
  onProgress: ({ completed, total, percent }) => {
    console.log(`${percent}% done (${completed}/${total})`);
  },
});

Stop on Error

const { results, errors } = await promisePool(tasks, {
  concurrency: 3,
  stopOnError: true, // Stop scheduling new tasks after first failure
});

Reusable Pool

import { createPool } from '@philiprehberger/promise-pool';

const pool = createPool({ concurrency: 3 });

// Tasks are queued and run with at most 3 concurrent
const result1 = pool.run(() => fetch('/api/1'));
const result2 = pool.run(() => fetch('/api/2'));
const result3 = pool.run(() => fetch('/api/3'));
const result4 = pool.run(() => fetch('/api/4')); // waits for a slot

API

| Export | Description | |--------|-------------| | promisePool(tasks, options?) | Execute tasks with concurrency limit, returns PoolResult | | createPool(options?) | Create a reusable pool with run() method |

PoolOptions

| Option | Type | Default | Description | |--------|------|---------|-------------| | concurrency | number | 5 | Max concurrent tasks | | stopOnError | boolean | false | Stop scheduling after first error | | onProgress | (progress) => void | — | Progress callback |

PoolResult<T>

| Property | Type | Description | |----------|------|-------------| | results | (T \| undefined)[] | Results in original order (undefined for failed tasks) | | errors | PoolError[] | Array of { index, error } for failed tasks |

Development

npm install
npm run build
npm test

License

MIT