A better streams API is possible for JavaScript

They propose just using an async iterator of UInt8Array. I almost like this idea, but it's not quite all the way there.

They propose this:

  type Stream = {
    next(): Promise }>
  }

  type Stream = {
    next(): { done, value: T } | Promise
  }

- I can easily make mine from theirs

- In theirs the conceptual "stream" is defined by an iterator of iterators, meaning you need a for loop of for loops to step through it. In mine it's just one iterator and it can be consumed with one for loop.

- I'm not limited to having only streams of integers, they are

- My way, if I define a sync transform over a sync input, the whole iteration can be sync making it possible to get and use the result in sync functions. This is huge as otherwise you have to write all the code twice: once with sync iterator and for loops and once with async iterators and for await loops.

- The problem with thrashing Promises when splitting input up into words goes away. With async iterators, creating two words means creating two promises. With stream iterators if you have the data available there's no need for promises at all, you just yield it.

- Stream iterators can help you manage concurrency, which is a huge thing that async iterators cannot do. Async iterators can't do this because if they see a promise they will always wait for it. That's the same as saying "if there is any concurrency, it will always be eliminated."

I may be naive in asking this, but what leads someone to building high perf data tools in JS? JS doesn't seem to me like it would be the tool of choice for such things

https://github.com/ralusek/streamie

allows you to do things like

    infiniteRecords
    .map(item => doSomeAsyncThing(item), { concurrency: 5 });

    infiniteRecords
    .map(item => doSomeAsyncSingularThing(item), { concurrency: 5 })
    .map(groupOf10 => doSomeBatchThing(groupsOf10), { batchSize: 10 })
    // Can flatten back to single items
    .map(item => backToSingleItem(item), { flatten: true });