[bmcahren]

Their first example is basically pretending basic promise concurrency on maps doesn't exist when it's been around before Promises were an official API (Search: bluebird promise map concurrency)

And the third examples are much easier to maintain with a simple function I drafted up for sake of argument `processArrayWithStages(array: T[], limit: number, stages: Array<(item: T) => Promise<T>>)`

In my experience, unless you're doing math in promises which I would recommend shifting to WASM, you're not going to feel the overhead of these intermediary arrays at scales that you shouldn't be in WASM already (meaning over several millions of entries).

The amazing people and teams working on V8 have done well to optimize these flows in the past four years because they are extremely common in popular applications. Strings aren't even copied in the sense you might think, you have a pointer to a chunk that can be extended and overwritten which incurs a penalty but saves tons of RAM.

processArrayWithStages: https://gist.github.com/DevBrent/0ee8d6bbd0517223ac1f95d952b...