which-builtin-type determines the type of a built-in JavaScript value, working across realms without relying on instanceof and without being misled by a constructor property. It is useful when you need a reliable way to classify values like arrays, typed arrays, dates, regexes, numbers, and functions.
Project status
- The repository shows at least one recent upstream push (2026-03-16), but the most recent published package updates in the provided history are from 2024-12-13 (v1.2.1), which suggests slower, likely maintenance-mode activity rather than steady feature work.
- Update cadence appears irregular, with relatively frequent changes in 2020-2024 (roughly quarterly to yearly), followed by a long gap since 2024-12-13, and no versioned updates shown between then and today (2026-09-10).
AI summary generated
Recent updates
v1.2.1
This release (v1.2.1) appears to be a dependency and internal refactor update, with no explicit user-facing release notes provided by the publisher. The code change is small (index.js swap from call-bind to call-bound), while package.json updates multiple dependency versions and slightly alters CI workflows.
v1.2.0
v1.2.0 adds first-party TypeScript definitions (index.d.ts) and updates the runtime implementation to use call-bind/callBound for Promise.prototype.then access. There are also CI workflow changes for the Node 10-20 and 20+ test ranges, plus dependency bumps (notably is-finalizationregistry). No release notes were provided by the publisher.
Featuresv1.1.4
Release v1.1.4 was published on 2024-07-29, but the publisher did not provide any release notes. No specific changes, fixes, or migration guidance are documented in the provided information.
v1.1.3
No release notes were provided for v1.1.3. The code diff indicates this release is primarily publishing and packaging metadata updates (exports/package metadata, npmignore generation, and CI workflow changes), plus some dev dependency bumps.
v1.1.2
Release v1.1.2 is primarily a dependency and internal refactor update for which-builtin-type. The provided release notes are empty (none given), so the actual behavior-affecting change is not documented there.
v1.1.1
This release (v1.1.1) updates the internal logic used to determine Symbol.toStringTag availability and bumps several dependencies, including linting and runtime packages. The only functional code change shown is a refactor of the @@toStringTag detection mechanism in the main entrypoint.
v1.1.0
This release (v1.1.0) significantly expands `which-builtin-type` detection for modern builtins like `Promise`, `WeakRef`, and `FinalizationRegistry`, and adds logic intended to prevent spoofed builtins via `constructor` and `Symbol.toStringTag`. No release notes were provided by the publisher, so the practical changes should be inferred from the code diff.
Featuresv1.0.1
This release (v1.0.1) appears to be largely tooling and dependency related, with changes focused on CI workflows, test/coverage setup, and various dev and runtime package bumps. The only direct code change shown in the diff is inside the test suite, and the public entrypoint implementation is not modified in the provided diff.
v1.0.0
This release is v1.0.0, published on 2020-01-25. No release notes were provided by the publisher, so there is no documented information about new features, fixes, breaking changes, or migration steps.