package-async
Loops for async functions.
Installation:
npm install @wildpeaks/async
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);