which-collection exports a function that tells you which built-in JavaScript collection type (Map, Set, WeakMap, WeakSet) a given value is. It works across realms without using `instanceof`, and it can detect the type even when Symbol.toStringTag is set. Useful for runtime type checks of collection objects.
Project status
- Actively maintained: The repository shows a recent upstream push on 2026-03-19, but published updates have been infrequent since 2024-03-08.
- Update cadence: There were updates in 2019-11-13 (v1.0.0), 2020-01-26 (v1.0.1), then a much longer gap to 2024-03-08 (v1.0.2), indicating a slow-moving cadence overall.
AI summary generated Today
Recent updates
v1.0.2
3/8/2024v1.0.2 primarily modernizes the project tooling, publishing configuration, and test/coverage setup, and adds TypeScript typings. The functional runtime code change in index.js appears to be typing-only (JSDoc), but several packaging and module-resolution metadata changes could impact how consumers resolve the package. Release notes were not provided by the publisher, so most changes below are effectively undocumented.
Featuresv1.0.1
1/26/2020Release v1.0.1 updates the package metadata and dependency versions, with no release notes provided by the publisher. The largest functional change in the diff is the addition of an npm package.exports map and version bump in package.json.
Featuresv1.0.0
11/13/2019The release is v1.0.0 (published 2019-11-13) 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 updates, or migration steps in the available materials.