Promise.all waits for all 50 promises to resolve, so if one of these promises takes 3s, while the other 49 are taking 0.5s, you're waisting 2.5s awaiting each batch.

The implementation is rather simple, but more than 3 LoC: https://github.com/whilenot-dev/promises-batched/blob/main/s...

I know. My point is you can do better without a library.