Provides an ESnext-compliant iterator helpers shim or polyfill for sync iterators, intended to work in older environments down to ES3. It adds helper methods like map, filter, reduce, and others to iterator constructors or Iterator.prototype (and is useful for build tooling and testing).
Project status
- Actively maintained: Yes, the source shows recent upstream activity (last upstream push on 2026-06-10) and multiple recent updates in 2026, including CI/test262 work (v1.3.3) rather than long periods of inactivity.
- Update cadence: Fast and recent, with updates on 2026-06-10 (v1.3.3), then again on 2026-04-10 (v1.3.2), and earlier in March 2026 (v1.3.1 and v1.3.0). Overall, it looks like an actively iterated development line rather than a sporadic one.
AI summary generated
Recent updates
v1.4.0
No release notes were provided for v1.4.0 in the supplied release_notes payload, so the documented change list is empty. The code diff shows v1.4.0 adds new iterator helper methods (chunks, join, windows) and also changes take/drop behavior for too-large finite limits.
Featuresv1.3.3
This release (v1.3.3) has no publisher-provided release notes, but the code diff and changelog show several spec-alignment fixes, mostly around iterator branding/properties, and Iterator.prototype.includes and zipKeyed edge case behavior. A significant amount of work is also focused on improving CI and adding a test262 test runner via a submodule.
Breakingv1.3.2
v1.3.2 makes extensive internal changes to iterator-helpers implementations, primarily around spec-compliant iterator closing and early-error handling. The GitHub release notes were not provided, but the code diff shows both behavioral changes (IteratorClose/IteratorStepValue handling) and a notable module export shape change across many entrypoint files.
v1.3.1
Release v1.3.1 contains a targeted change to the `Iterator.prototype.includes` polyfill implementation. The provided publisher release notes are empty, so the actual behavior change is only visible by inspecting the code diff.
v1.3.0
Release v1.3.0 was published on 2026-03-11, but no release notes were provided by the publisher. Without documented changes, developers should review the actual diff between the previous version and v1.3.0 to identify potential API, behavior, and configuration changes.
v1.2.2
No release notes were provided for v1.2.2. The code diff shows a broad internal refactor, largely upgrading the project to es-abstract 2025 algorithms and changing some iterator helper behaviors (notably string handling modes and generator state handling), without any corresponding release-note detail.
v1.2.1
No publisher release notes were provided for v1.2.1. The repository documentation instead reflects this release primarily through a changelog entry and the actual code changes, which include iterator-spec compliance fixes and dependency refactors.
v1.2.0
v1.2.0 introduces new iterator helpers, Iterator.zip and Iterator.zipKeyed, including support for mode (shortest, longest, strict) and longest-padding behavior. The change also introduces new internal infrastructure for joint-iteration semantics (closing multiple iterators, plural underlying iterator slots), and updates several existing helpers to match the new internal slot shape.
Featuresv1.1.0
Version v1.1.0 adds a new iterator helper, `Iterator.concat`, including implementation, polyfill selection, and shim wiring into the package’s auto-shim entrypoints. The release notes were not provided by the publisher, so the changelog and code changes (new exports and new shimming behavior) are not documented there.
Featuresv1.0.19
v1.0.19 primarily updates iterator helper polyfills for drop, filter, flatMap, and map to account for a V8/Chromium bug (Chromium issue 336839115). The repo also bumps the es-abstract dependency and removes some unused internal algorithms (AOs), with corresponding test and documentation adjustments.
v1.0.18
Release v1.0.18 has no publisher release notes provided. The code diff shows a dependency refresh (notably moving from es-abstract 2023 algorithm modules to es-abstract 2024) plus a targeted change in generator completion handling.
v1.0.17
Release v1.0.17 was published on 2024-02-13, but the publisher provided no release notes. Because no change log details are available, developers should treat this upgrade as potentially containing undocumented changes and verify compatibility by checking the code diff and running the test suite.