GeezerVison

At first, when I read that note I thought I should do this:

import { Readable } from 'node:stream';

const totalViews = await Readable.from(videosUrl)
  .map((url) => url, { concurrency: 2 })
  .reduce(async (total, url) => {
    const views = await getViewsAsync(url)
    total + views
  }, 0);

console.log(totalViews);

This did not work and does not make any sense as the map items are emitted in the order that got from the readable stream.

So I thought of changing to note to recommend implementing reduce using .forEach with concurrency but then I understand what @benjamingr meant when he wrote that note - because the only way you will need concurrency is if you do some async operation (because sync block the loop - bla bla) and that operation can be parallelized so I updated the note with an example

@benjamingr, hope this is what you meant 😅