Package

which-collection

Which kind of Collection (Map, Set, WeakMap, WeakSet) is this JavaScript value? Works cross-realm, without `instanceof`, and despite Symbol.toStringTag.

v1.0.2, 8 Mar 2024MITCommonJSTypes: Bundled

$ npm install which-collection

npm GitHub Homepage

Key numbers

As of 25 Sept 2026

Weekly downloads: 60.6m; +102% over 12 months
Gzip bundle size: -; No Bundlephobia data
Dependencies: 4; Direct, from package.json
Last release: 2 years ago; v1.0.2
GitHub stars: 10; 4 forks
Open issues / PRs: 1 / 0
Contributors: 1
Commits, last 52 weeks: 6

Downloads

Last week 2026-09-15 to 2026-09-21

Weekly npm downloads, one point per week, weeks starting 23 Sept 2025 to 15 Sept 2026. The y axis starts at zero.

60,636,376 downloads last week, 296,070,809 in the last month. The 12-month change of +102% compares the average of the last 4 weeks with the first 4 weeks of the series.

Maintenance

Releases, last 12 months: 03 in total
Latest version: 1.0.2, 8 Mar 20242 years ago
First published: 13 Nov 2019
Last push to GitHub: 19 Mar 2026190 days before the snapshot
Repository archived: No
Open issues: 1
Open pull requests: 0
Commits, last 52 weeks: 6
Dependents on npm: 648

Major versions

v1 first release 1.0.0, 13 Nov 2019

Recent releases

Version	Published
1.0.2	8 Mar 2024
1.0.1	26 Jan 2020
1.0.0	13 Nov 2019

Compatibility

Module format: CommonJSFrom package.json type, main and exports fields
TypeScript types: Bundled
Node.js engine range: >= 0.4
Runtimes: -
Unpacked size (npm): 20 kB
Dependencies (4): is-mapis-setis-weakmapis-weakset

Install

npm install which-collection

CDN

jsDelivrhttps://cdn.jsdelivr.net/npm/which-collection@1.0.2/
unpkghttps://unpkg.com/which-collection@1.0.2/
esm.shhttps://esm.sh/which-collection@1.0.2

Sources: npm registry, npm downloads API, GitHub API. Data fetched 25 Sept 2026.

Indexability: Not indexed (discovery only): no category.