Implementation of Readable iteration helpers that does not rely on Async Iteration

[lukiano]

Hi, I'd like to offer an alternative implementation of Readable iteration helpers like find() that don't rely on for await (...) to consume items from the stream. This results in improved performance when the data is already available, such as when creating a Readable from an array, as shown in the attached screenshot (executed on a MacBook M2 Max).

The main con is increased duplication and code complexity. My understanding is that these helpers are still in the experimental phase, which I hope makes a change like this easier to accept.

There are many commits in the branch, but I'll squash them before merging.

The affected helpers are

• map()
• filter()
• reduce()
• find()
• toArray()
• some()
• every()
• drop()

Unaffected helpers:

• flatmap()
• take()

There's also a change to the from() method that increases the buffer watermark when the source is an array of data.
At first, I coded the changes manually, but eventually I had assistance from AI to keep backward compatibility. Still, there's a small break as can be seen in the updated test in test/parallel/test-stream-reduce.js.

The file benchmark/streams/operator-throughput.js allows interested parties to run the benchmarks on their computers or modify them to try other scenarios. I can remove it before merging.

[nodejs-github-bot]

Review requested:

• @nodejs/performance
• @nodejs/streams