KRNL-221 add callChunked array function

[Dosexe]

Changes

Add callChunked function

Checklist

• Apply one of following labels; major, minor, patch or skip-release
• I've updated the documentation, or no changes were necessary
• I've updated the tests, or no changes were necessary

[rupert-mckay]

🔶 Very surprised that you don't use the chunk function directly above. If you did you could have:

const chunks = chunk(array, chunkSize)
for (const arrayChunk of chunks) {
  await processFn(arrayChunk)
} 

[rupert-mckay]

This can also be done as a promise reducer:

chunk(array, chunkSize)
  .reduce(
    (promiseChain, chunk) => promiseChain.then(() => callback(chunk)),
    Promise.resolve()
  )

[kibertoad]

for of is slower than old-school looping, so for a low-level library I would recommend keeping the original approach.
see https://github.com/kibertoad/nodejs-benchmark-tournament/blob/master/loops/_results/results.md

[kibertoad]

And I'm not sure how I feel about using reduce here, sounds like an overcomplication. Original version is pretty simple.

[Dosexe]

So, what should I do at the end?:)

[kibertoad]

Personally I see no reason to change this code, for me it is as simple as it needs to be, I see no advantages, performance or complexity-wise in suggested alternatives.
@rupert-mckay This is a yellow, non-blocking-but-please-explain-your-position comment, right?

[rupert-mckay]

Yup. Happy for the PR to merge as-is. Still a bit surprised that the chunk helper isn't used, but it's not important.

[rupert-mckay]

🟢 Feel free to ignore this comment as beyond the scope of this PR... but I really don't like what's going on in the chunk function. Ignoring no-unsafe-return is dangerous, and the implementation is especially fiddly and prone to error.

Chunking can be expressed rather naturally with a generator function which yields one chunk at a time. We can gather them into an array with Array.from. Here's an example alternative implementation:

function* chunkGenerator<Item>(
  array: readonly Item[],
  chunkSize = 1,
) {
  let index = 0;

  while (index < array.length) {
    yield array.slice(index, index + chunkSize);
    index += chunkSize;
  }
}

const chunk = <Item>(
  array: readonly Item[],
  chunkSize = 1,
) => Array.from(chunkGenerator(array, chunkSize));

[kibertoad]

Feel free to ignore this comment

This seems to contradict the RED flag.

[rupert-mckay]

That's fair. My instinct had been "this is something I feel very strongly about"... but it is naturally contradicted by "... but it might not at all be relevant to this PR".

I'll edit to 🟢