@wildpeaks/async

package-async

Loops for async functions.

Installation:

npm install @wildpeaks/async

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asyncArrayMap

Similar to Array.map, except the mapper function should return a Promise, and it can optionally limit the number of Promises running at once (e.g. useful for calling a rate-limited API for example).

Syntax:

type CallbackType = (value: any, index: number, array: any[]) => Promise;

function asyncArrayMap(
	array: any[],
	callback: CallbackType,
	limit: number
): Promise<any[]>

Parameters:

• array: Arbitrary list of values to process
• callback: Async function that produces an element of the new Array
• limit: Number of promises that can run at once (0 = no limit, 1 = only one at a time, 2 = two at once maximum, etc…)

Examples

Process all values in parallel (default, limit 0):

const {asyncArrayMap} = require('@wildpeaks/async');

const words = ['Aaa', 'Bbb', 'Ccc'];
const translations = await asyncArrayMap(words, async word => {
	const translated = await translate(word);
	return word + ' translates to ' + translated;
});

Only one at the time, one after the other (limit 1):

async function mapWord(word){
	const translated = await translate(word);
	return word + ' translates to ' + translated;
}

const {asyncArrayMap} = require('@wildpeaks/async');
const translations = await asyncArrayMap(['Aaa', 'Bbb', 'Ccc'], mapWord, 1);

Up to 5 at the same time in parallel (limit 5):

async function mapWord(word){
	const translated = await translate(word);
	return word + ' translates to ' + translated;
}

const {asyncArrayMap} = require('@wildpeaks/async');
const translations = await asyncArrayMap(['Aaa', 'Bbb', 'Ccc'], mapWord, 5);

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