[masklinn]

And it's important to note that the comparison does not make sense: TFAA seems to believe "async.sortBy" performs an asynchronous sort (e.g. delegates the sorting to a threadpool) and that's how he implemented his own "SortAsync": to perform a regular Array.Sort in its own task.

But that's not what async.sortBy does according to its documentation, async.sortBy is used to sort using an async comparator/key function e.g. to sort file names using a stat(2) call, the .Net version would have to sort using an asynchronous IComparator of some sort.

edit: plus, for some reason the benchmark explicitly parses the input strings to floats in javascript (and sorts using that), but seems to sort the raw bytes in the .net version. The C# version further performs the string split in the sparked task, where it's performed in request in JS (not that it'd help since — as I mentioned — the sort itself is incorrect)

second edit: to be fair, I like neither technology and am not a specialist in either, I have a pretty basic basic grasp of both and thus may have made mistakes in my cursory reading, if I have and somebody knows better don't hesitate correcting me.

But as you may see from the paragraphs above, as far as I understand the code this comparison is complete nonsense (even ignoring the rather dubious higher level case of reading a single big file in memory at once, sorting it and extracting a bit of stat, which is unlikely to be IO-bound)