Cleanup iterator helpers by jedel1043 · Pull Request #5236 · boa-dev/boa

jedel1043 · 2026-03-23T09:47:23Z

Kinda big refactor of our iterator helpers, but this makes it such that they reuse the same coroutine machinery that Array.fromAsync uses, removing many of the expect calls that were in place, which was a consequence of having to use an enum to represent all iterator helpers.

This also cleans up the intrinsic initialization code, which was kinda wrong in some places and caused a bug where the iterator returned by generator functions wouldn't have the iterator prototype setup correctly.

This puts us at 100% conformance (not counting joint iterators) for the Iterator.prototype suite BTW

github-actions · 2026-03-23T10:05:42Z

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,963	52,963	0
Passed	50,545	50,732	+187
Ignored	1,426	1,426	0
Failed	992	805	-187
Panics	2	0	-2
Conformance	95.43%	95.79%	+0.35%

Fixed tests (187):

test/built-ins/Iterator/prototype/some/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/some/predicate-returns-non-boolean.js (previously Failed)
test/built-ins/Iterator/prototype/some/predicate-this.js (previously Failed)
test/built-ins/Iterator/prototype/some/predicate-returns-falsey.js (previously Failed)
test/built-ins/Iterator/prototype/some/predicate-returns-truthy.js (previously Failed)
test/built-ins/Iterator/prototype/some/predicate-args.js (previously Failed)
test/built-ins/Iterator/prototype/some/predicate-returns-falsey-then-truthy.js (previously Failed)
test/built-ins/Iterator/prototype/some/iterator-has-no-return.js (previously Failed)
test/built-ins/Iterator/prototype/some/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/some/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/some/callable.js (previously Failed)
test/built-ins/Iterator/prototype/some/result-is-boolean.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/reducer-args-no-initial-value.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/reducer-args-initial-value.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/reducer-this.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/iterator-yields-once-initial-value.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/iterator-already-exhausted-initial-value.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/callable.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/non-callable-reducer.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/iterator-already-exhausted-no-initial-value.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/reducer-memo-can-be-any-type.js (previously Failed)
test/built-ins/Iterator/prototype/reduce/iterator-yields-once-no-initial-value.js (previously Failed)
test/built-ins/Iterator/prototype/constructor/weird-setter.js (previously Failed)
test/built-ins/Iterator/prototype/find/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/find/predicate-returns-non-boolean.js (previously Failed)
test/built-ins/Iterator/prototype/find/predicate-this.js (previously Failed)
test/built-ins/Iterator/prototype/find/predicate-returns-falsey.js (previously Failed)
test/built-ins/Iterator/prototype/find/predicate-returns-truthy.js (previously Failed)
test/built-ins/Iterator/prototype/find/predicate-args.js (previously Failed)
test/built-ins/Iterator/prototype/find/predicate-returns-falsey-then-truthy.js (previously Failed)
test/built-ins/Iterator/prototype/find/iterator-has-no-return.js (previously Failed)
test/built-ins/Iterator/prototype/find/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/find/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/find/callable.js (previously Failed)
test/built-ins/Iterator/prototype/map/returned-iterator-yields-mapper-return-values.js (previously Failed)
test/built-ins/Iterator/prototype/map/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/map/throws-typeerror-when-generator-is-running.js (previously Failed)
test/built-ins/Iterator/prototype/map/mapper-args.js (previously Failed)
test/built-ins/Iterator/prototype/map/mapper-this.js (previously Failed)
test/built-ins/Iterator/prototype/map/result-is-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/map/underlying-iterator-advanced-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/map/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/map/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/map/underlying-iterator-closed.js (previously Failed)
test/built-ins/Iterator/prototype/map/underlying-iterator-closed-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/map/callable.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/flattens-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/flattens-iterable.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/iterable-to-iterator-fallback.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/throws-typeerror-when-generator-is-running.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/mapper-args.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/flattens-only-depth-1.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/mapper-this.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/result-is-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/underlying-iterator-advanced-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/return-is-forwarded-to-mapper-result.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/mapper-returns-closed-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/mapper-returns-non-object.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/underlying-iterator-closed.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/underlying-iterator-closed-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/callable.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/iterable-primitives-are-not-flattened.js (previously Failed)
test/built-ins/Iterator/prototype/flatMap/strings-are-not-flattened.js (previously Failed)
test/built-ins/Iterator/prototype/every/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/every/predicate-returns-non-boolean.js (previously Failed)
test/built-ins/Iterator/prototype/every/predicate-this.js (previously Failed)
test/built-ins/Iterator/prototype/every/predicate-returns-falsey.js (previously Failed)
test/built-ins/Iterator/prototype/every/predicate-returns-truthy.js (previously Failed)
test/built-ins/Iterator/prototype/every/predicate-args.js (previously Failed)
test/built-ins/Iterator/prototype/every/iterator-has-no-return.js (previously Failed)
test/built-ins/Iterator/prototype/every/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/every/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/every/callable.js (previously Failed)
test/built-ins/Iterator/prototype/every/result-is-boolean.js (previously Failed)
test/built-ins/Iterator/prototype/every/predicate-returns-truthy-then-falsey.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/fn-called-for-each-yielded-value.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/fn-this.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/result-is-undefined.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/callable.js (previously Failed)
test/built-ins/Iterator/prototype/forEach/fn-args.js (previously Failed)
test/built-ins/Iterator/prototype/filter/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/filter/predicate-returns-non-boolean.js (previously Failed)
test/built-ins/Iterator/prototype/filter/predicate-this.js (previously Failed)
test/built-ins/Iterator/prototype/filter/predicate-args.js (previously Failed)
test/built-ins/Iterator/prototype/filter/throws-typeerror-when-generator-is-running.js (previously Failed)
test/built-ins/Iterator/prototype/filter/result-is-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/filter/underlying-iterator-advanced-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/filter/predicate-filters.js (previously Failed)
test/built-ins/Iterator/prototype/filter/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/filter/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/filter/underlying-iterator-closed.js (previously Failed)
test/built-ins/Iterator/prototype/filter/underlying-iterator-closed-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/filter/callable.js (previously Failed)
test/built-ins/Iterator/prototype/drop/limit-greater-than-total.js (previously Failed)
test/built-ins/Iterator/prototype/drop/limit-rangeerror.js (previously Failed)
test/built-ins/Iterator/prototype/drop/limit-equals-total.js (previously Failed)
test/built-ins/Iterator/prototype/drop/throws-typeerror-when-generator-is-running.js (previously Panic)
test/built-ins/Iterator/prototype/drop/result-is-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/drop/underlying-iterator-advanced-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/drop/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/drop/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/drop/limit-tonumber-throws.js (previously Failed)
test/built-ins/Iterator/prototype/drop/underlying-iterator-closed.js (previously Failed)
test/built-ins/Iterator/prototype/drop/underlying-iterator-closed-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/drop/callable.js (previously Failed)
test/built-ins/Iterator/prototype/drop/limit-tonumber.js (previously Failed)
test/built-ins/Iterator/prototype/drop/limit-less-than-total.js (previously Failed)
test/built-ins/Iterator/prototype/Symbol.toStringTag/weird-setter.js (previously Failed)
test/built-ins/Iterator/prototype/take/limit-rangeerror.js (previously Failed)
test/built-ins/Iterator/prototype/take/throws-typeerror-when-generator-is-running.js (previously Panic)
test/built-ins/Iterator/prototype/take/result-is-iterator.js (previously Failed)
test/built-ins/Iterator/prototype/take/underlying-iterator-advanced-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/take/limit-greater-than-or-equal-to-total.js (previously Failed)
test/built-ins/Iterator/prototype/take/argument-validation-failure-closes-underlying.js (previously Failed)
test/built-ins/Iterator/prototype/take/argument-effect-order.js (previously Failed)
test/built-ins/Iterator/prototype/take/limit-tonumber-throws.js (previously Failed)
test/built-ins/Iterator/prototype/take/underlying-iterator-closed.js (previously Failed)
test/built-ins/Iterator/prototype/take/underlying-iterator-closed-in-parallel.js (previously Failed)
test/built-ins/Iterator/prototype/take/callable.js (previously Failed)
test/built-ins/Iterator/prototype/take/limit-tonumber.js (previously Failed)
test/built-ins/Iterator/prototype/take/limit-less-than-total.js (previously Failed)
test/built-ins/Iterator/prototype/toArray/iterator-already-exhausted.js (previously Failed)
test/built-ins/Iterator/prototype/toArray/callable.js (previously Failed)
test/built-ins/Iterator/from/iterable-primitives.js (previously Failed)
test/built-ins/Iterator/from/result-proto.js (previously Failed)
test/built-ins/Iterator/concat/throws-typeerror-when-generator-is-running-return.js (previously Failed)
test/built-ins/Object/prototype/toString/symbol-tag-map-builtin.js (previously Failed)
test/built-ins/Object/prototype/toString/symbol-tag-set-builtin.js (previously Failed)
test/built-ins/Object/prototype/toString/symbol-tag-array-builtin.js (previously Failed)
test/built-ins/Object/prototype/toString/symbol-tag-string-builtin.js (previously Failed)
test/staging/sm/Iterator/prototype/lazy-methods-handle-empty-iterators.js (previously Failed)
test/staging/sm/Iterator/prototype/lazy-methods-reentry-not-close-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/iterator-helper-methods-throw-on-generators.js (previously Failed)
test/staging/sm/Iterator/prototype/generator-methods-throw-on-iterator-helpers.js (previously Failed)
test/staging/sm/Iterator/prototype/iterator-helpers-from-other-global.js (previously Failed)
test/staging/sm/Iterator/prototype/take-drop-throw-eagerly-on-negative.js (previously Failed)
test/staging/sm/Iterator/prototype/lazy-methods-throw-on-reentry.js (previously Failed)
test/staging/sm/Iterator/prototype/some/coerce-result-to-boolean.js (previously Failed)
test/staging/sm/Iterator/prototype/some/return-false-if-none-match.js (previously Failed)
test/staging/sm/Iterator/prototype/some/check-fn-after-getting-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/some/short-circuit-on-true.js (previously Failed)
test/staging/sm/Iterator/prototype/reduce/iterator-empty-return-initial-value.js (previously Failed)
test/staging/sm/Iterator/prototype/reduce/left-associative.js (previously Failed)
test/staging/sm/Iterator/prototype/reduce/no-initial-value-set-accumulator-to-first-value.js (previously Failed)
test/staging/sm/Iterator/prototype/reduce/check-fn-after-getting-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/reduce/reduce.js (previously Failed)
test/staging/sm/Iterator/prototype/reduce/accumulator-set-to-initial-value.js (previously Failed)
test/staging/sm/Iterator/prototype/find/short-circuit-on-match.js (previously Failed)
test/staging/sm/Iterator/prototype/find/coerce-result-to-boolean.js (previously Failed)
test/staging/sm/Iterator/prototype/find/check-fn-after-getting-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/find/return-undefined-if-none-match.js (previously Failed)
test/staging/sm/Iterator/prototype/map/interleaved-map-calls.js (previously Failed)
test/staging/sm/Iterator/prototype/map/call-next-on-iterator-while-iterating.js (previously Failed)
test/staging/sm/Iterator/prototype/map/reenter-map-generator-from-mapper.js (previously Failed)
test/staging/sm/Iterator/prototype/map/clobber-symbol.js (previously Failed)
test/staging/sm/Iterator/prototype/map/mutate-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/map/mutate-iterator-after-done.js (previously Failed)
test/staging/sm/Iterator/prototype/map/output-at-generator-end.js (previously Failed)
test/staging/sm/Iterator/prototype/flatMap/inner-generator.js (previously Failed)
test/staging/sm/Iterator/prototype/flatMap/inner-empty-iterable.js (previously Failed)
test/staging/sm/Iterator/prototype/flatMap/throw-when-inner-not-iterable.js (previously Failed)
test/staging/sm/Iterator/prototype/flatMap/close-iterator-when-inner-value-throws.js (previously Failed)
test/staging/sm/Iterator/prototype/flatMap/close-iterator-when-inner-complete-throws.js (previously Failed)
test/staging/sm/Iterator/prototype/flatMap/close-iterator-when-inner-next-throws.js (previously Failed)
test/staging/sm/Iterator/prototype/every/short-circuit-on-false.js (previously Failed)
test/staging/sm/Iterator/prototype/every/coerce-result-to-boolean.js (previously Failed)
test/staging/sm/Iterator/prototype/every/check-fn-after-getting-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/every/return-true-if-all-match.js (previously Failed)
test/staging/sm/Iterator/prototype/forEach/forEach.js (previously Failed)
test/staging/sm/Iterator/prototype/forEach/check-fn-after-getting-iterator.js (previously Failed)
test/staging/sm/Iterator/prototype/filter/coerce-result-to-boolean.js (previously Failed)
test/staging/sm/Iterator/prototype/drop/drop-more-than-available.js (previously Failed)
test/staging/sm/Iterator/prototype/take/take-more-than-available.js (previously Failed)
test/staging/sm/Iterator/prototype/toArray/toArray.js (previously Failed)
test/staging/sm/Iterator/prototype/toArray/iterator-empty.js (previously Failed)
test/staging/sm/Iterator/prototype/toArray/create-in-current-realm.js (previously Failed)
test/staging/sm/Iterator/from/return-iterator-if-iterable.js (previously Failed)
test/staging/sm/Iterator/from/wrap-new-global.js (previously Failed)
test/staging/sm/Array/from_primitive.js (previously Failed)

Tested main commit: 66a1cd268ce6006918032b5d0f98d3a63c81b188
Tested PR commit: ae6798a78c073aba31e6d96dfc022f28d9c560ba
Compare commits: 66a1cd2...ae6798a

codecov · 2026-03-23T11:11:46Z

Codecov Report

❌ Patch coverage is 68.19484% with 222 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.70%. Comparing base (6ddc2b4) to head (ae6798a).
⚠️ Report is 916 commits behind head on main.

Files with missing lines	Patch %	Lines
core/engine/src/builtins/array/from_async.rs	0.00%	88 Missing ⚠️
...engine/src/builtins/iterable/iterator_prototype.rs	73.56%	69 Missing ⚠️
.../src/builtins/iterable/iterator_helper/flat_map.rs	76.11%	16 Missing ⚠️
core/engine/src/object/builtins/jspromise.rs	0.00%	15 Missing ⚠️
...ngine/src/builtins/iterable/iterator_helper/mod.rs	88.13%	7 Missing ⚠️
...gine/src/builtins/iterable/iterator_helper/drop.rs	82.14%	5 Missing ⚠️
...ne/src/builtins/iterable/iterator_helper/concat.rs	87.87%	4 Missing ⚠️
...ne/src/builtins/iterable/iterator_helper/filter.rs	87.87%	4 Missing ⚠️
...gine/src/builtins/iterable/iterator_helper/take.rs	84.00%	4 Missing ⚠️
core/engine/src/native_function/continuation.rs	66.66%	4 Missing ⚠️
... and 3 more

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5236       +/-   ##
===========================================
+ Coverage   47.24%   59.70%   +12.45%     
===========================================
  Files         476      589      +113     
  Lines       46892    63408    +16516     
===========================================
+ Hits        22154    37856    +15702     
- Misses      24738    25552      +814

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jedel1043 added 4 commits March 23, 2026 03:33

Cleanup iterator helpers

1cc1a3c

Finish implementation

6415d0c

Fix all test regressions

8aaa2a2

Format launch.json

ed99c67

jedel1043 requested a review from a team as a code owner March 23, 2026 09:47

github-actions bot added the Waiting On Review Waiting on reviews from the maintainers label Mar 23, 2026

github-actions bot added this to the v1.0.0 milestone Mar 23, 2026

github-actions bot added C-Builtins PRs and Issues related to builtins/intrinsics C-GC Issue related to garbage collection labels Mar 23, 2026

jedel1043 added 2 commits March 23, 2026 03:49

Fix prettier & typos

45cb235

Fix docs

c448a7c

jedel1043 added 2 commits March 23, 2026 04:43

Remove standalone iterator prototype

3020d35

Fix tests

5ad1283

github-actions bot added the C-Tests Issues and PRs related to the tests. label Mar 23, 2026

Fix launch.json

ae6798a

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