Generator .take() not returning well formed iterable?

[rebyul]

Version

24.1.0, 24.0.2, 22.16.0

Platform

Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:49 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6000 arm64

Subsystem

No response

What steps will reproduce the bug?

function* fibonacci() {
  let current = 1;
  let next = 1;
  while (true) {
    yield current;
    [current, next] = [next, current + next];
  }
}

// Correct output
const fibGen = fibonacci();
let iter1 = fibGen.take(3);
console.log(iter1.next().value); // 1
console.log(iter1.next().value); // 1
console.log(iter1.next().value); // 2
iter1 = fibGen.take(3);
console.log(iter1.next().value); // 3
console.log(iter1.next().value); // 5
console.log(iter1.next().value); // 8

// Incorrect output?
const fibGen2 = fibonacci();
let iter2 = fibGen2.take(3);
let takeToArray = Array.from(iter2);
console.log(takeToArray); // Outputs [1, 1, 2]
iter2 = fibGen2.take(3);
takeToArray = Array.from(iter2);
console.log(takeToArray); // Output: [] Expected: [3,5,8]

How often does it reproduce? Is there a required condition?

Consistently reproduced with above example code

What is the expected behavior? Why is that the expected behavior?

Expecting the next take(n) on the generator to return all values up to max take parameter (n) and Array.from() to correctly return generated values

What do you see instead?

empty array ([])

Additional information

Thank you for all the work the team does :)
I am not sure if I am using Iterator.prototype.take correctly, I have read the documentation at [mdn web docs] (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/take#using_take) and think I am using it correctly.
Apologies I cannot implement a fix, I am not proficient in C++ or the nodejs project.
I would gladly contribute if someone could give me some direction!
Thank you for your time.

[Renegade334]

This is the language specification. Iterator helpers close the underlying iterator when the helper has emitted its final result.

In general, once an iterator has been wrapped by an iterator helper object, the underlying iterator should not be consumed directly.

[rebyul]

Ah so by passing the iterator to Array.from(), the iterator has been closed: did I understand this correctly?

[Renegade334]

In essence, yes: Array.from() consumes the iterator helper to completion, and the moment the helper completes, it also closes the underlying generator.

Consider the following:

function *generatorFunction() { ... }

const generator = generatorFunction();
const iteratorHelper = generator.take(n);

// consume the iterator helper
for (const value of iteratorHelper) { }

// when the iterator helper is closed, the wrapped generator is implicitly closed as well
const result = generator.next();
assert(result.done === true);

This isn't a Node.js issue; if you need more support with the language feature, somewhere like the Discord server would be a more appropriate venue.

[rebyul]

Apologies for my lack of understanding, i realised the iterator helper you were referring to was not the array, but the return value of take() and was reading the ecma specs.
Thank you for the explanation, if this is expected behavior then that's great. I'll study up some more!