INNER CODE UNIT · JavaScript

groupBy

pegaltier/awesome-utils-dev · utils-script/jsfunctions.js:31

const groupBy = (x,f)=>x.reduce((a,b,i)=>((a[f(b,i,x)]||=[]).push(b),a),{});

// https://advancedweb.hu/how-to-use-async-functions-with-array-map-in-javascript/
const mapInGroups = (arr, iteratee, groupSize) => {
	const groups = groupBy(arr, (_v, i) => Math.floor(i / groupSize));

	return Object.values(groups)
		.reduce(async (memo, group) => [
			...(await memo),
			...(await Promise.all(group.map(iteratee)))
		], []);
};

const res = await mapInGroups(arr, async (v) => {
	console.log(`S ${v}`);
	await sleep(v);
	console.log(`F ${v}`);
	return v + 1;

View source record →