fast-async-pool/README.md

Run multiple promise-returning & async functions with limited concurrency with low overhead

# fast-async-pool

similar to [p-map](https://www.npmjs.com/package/p-map) or [tiny-async-pool](https://www.npmjs.com/package/tiny-async-pool), fast-async-pool run async/promise returning functions with limited concurrency and low overhead.

## Install

```
$ npm install fast-async-pool
```

## Usage

```js
import asyncPool from 'fast-async-pool';
import fetch from 'cross-fetch';

const sites = [
	'https://jestjs.io',
	'https://github.com',
  'https://www.npmjs.com',
  'https://www.solidjs.com'
];

const pages = await asyncPool(2, sites, async site => {
	const response = await fetch(site);
  return response.text();
});

console.log(pages);
```

## API

### asyncPool(limit, array, fn)

Returns a `Promise` that is fulfilled when all promises generated by mapping `array` to `fn` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values returned from `fn` in `array` order.
#### limit

concurrency limit

Type: `number` >= 1
#### array

Type: `Array<Promise<unknown> | unknown>`

#### fn(element, index, array)

Type: `Function`

Expected to return a `Promise` or value.