Merge asynchronous sequences using built-in promises

I encountered a problem while trying to implement the logic for combining various types of iterables in a list, which includes Iterable, Iterator, AsyncIterable, and AsyncIterator. My goal is to combine them together to achieve the same output as RXJS's combineLatestWith.

You can find the source code here, and also in my documentation for the operator (link):

(Check out the complete playground link at the bottom)

function combineAsync<T>(iterable: AsyncIterable<T>, ...values: AnyIterable<T>[]): AsyncIterable<any[]> {
    // Implementation code goes here
}

When passing 3 parameters: p1, p2(8), p3(7), defined as:

// Definitions of p1, p2, p3 go here

The expected result was:

[1, 2, 1] 
[2, 2, 1] 
// Remaining values truncated for brevity

Instead, I'm currently getting only part of the expected output.

I've spent considerable time debugging this complex asynchronous issue but haven't been able to solve it yet. If you have any insights or suggestions, they would be greatly appreciated!

Access the full playground here.

UPDATE

To demonstrate that the correct values do exist within the code, here's an updated version with added console logs.

Answer №1

Vitaly, you've presented a fascinating problem! :) Reusing promises that are already in progress within a Promise.race() scenario can indeed be quite tricky, but not impossible.

While error handling and rejection are not currently addressed in this code snippet, they can certainly be incorporated later once everything is running smoothly.

class CachedIterator<T>{
    // Class implementation details go here
}

Playground Link

Older Playground Link

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