is-regex is a JavaScript module that checks whether a given value is a JS regular expression, including cases that work across realms and iframes. It can be useful in validation logic where you need to distinguish regex objects from other values, for example returning true for /a/g and new RegExp('a','g').
Project status
- Active maintenance: The upstream repo shows a recent push on 2026-04-08, which suggests it is not completely abandoned, though the most recent published updates we can see are older.
- Update cadence: The latest listed published update is v1.2.1 (2024-12-12), about 17 months before today (2026-06-09), with no newer published updates shown, despite the 2026 upstream push. This points to sporadic maintenance rather than steady releases.
AI summary generated
Recent updates
v1.2.1
Version bump to v1.2.1 with a small internal refactor in index.js and dependency updates. The publisher release notes are missing, so the changes below are only discoverable from the actual diff.
v1.2.0
No release notes were provided in the publisher metadata for v1.2.0. The diff shows a refactor of the runtime isRegex implementation (and its TypeScript typings) plus broader build and CI packaging changes.
v1.1.4
Release v1.1.4 was published on 2021-08-06, but no release notes were provided by the publisher. As a result, there is no documented information about new features, breaking changes, bug fixes, security, performance, or dependency updates in this release.
v1.1.3
Release v1.1.3 contains internal changes to how the library detects Symbol.toStringTag support, plus tooling and CI updates. There were no publisher-provided release notes, so the behavioral change in symbol detection (and dependency bumps) is effectively undocumented for consumers upgrading.
v1.1.2
v1.1.2 does not include release-note details, but the diff shows the main functional change is in is-regex's core detection logic (index.js) switching to call-bind based method binding for robustness. The remainder of the changes are primarily CI/test infrastructure updates and dependency/script updates.
Securityv1.1.1
This patch release updates the core `is-regex` implementation and adjusts tests, with no publisher-provided release notes. The key functional change is a new/returned `lastIndex` property check in `index.js`, which also makes the function perform an observable operation against Proxies.
v1.1.0
This release updates the RegExp detection implementation used by `is-regex`. It switches to a `badStringifier`-based approach around `RegExp.prototype.exec` and adds tests to ensure the detection does not trigger observable Proxy operations.
v1.0.5
v1.0.5 contains mostly repository and tooling updates (CI/workflows, linting/security tooling, and test layout), along with a small runtime dependency bump. The only direct change in the library code shown (index.js) is an eslint-related comment around a `lastIndex` mutation, with no apparent behavioral change.
Securityv1.0.4
v1.0.4 updates the core `is-regex` detection logic in `index.js`. The main behavioral change is around how `lastIndex` is handled during detection, plus stricter gating of which RegExp-like objects qualify.
v1.0.3
Release v1.0.3 was published on 2015-01-30, but no release notes were provided by the publisher. As a result, there is insufficient information to identify specific new features, fixes, or compatibility changes included in this version.