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JS
Package

is

the definitive JavaScript type testing library

v3.3.2, 19 Jul 2025MITCommonJSTypes: NoneTesting
$ npm install is
npmGitHubHomepage

Key numbers

As of 25 Sept 2026
Weekly downloads
2.7m
+40% over 12 months
Gzip bundle size
-
No Bundlephobia data
Dependencies
0
Direct, from package.json
Last release
1 year ago
v3.3.2
GitHub stars
194
26 forks
Open issues / PRs
0 / 0
Contributors
-
Commits, last 52 weeks
1

Downloads

Last week 2026-09-15 to 2026-09-21
02m4m6mSept 2025Mar 2026Sept 2026High 4m (25 Aug 2026)Low 1.3m (23 Dec 2025)
Weekly npm downloads, one point per week, weeks starting 23 Sept 2025 to 15 Sept 2026. The y axis starts at zero.

2,712,145 downloads last week, 13,263,376 in the last month. The 12-month change of +40% compares the average of the last 4 weeks with the first 4 weeks of the series.

Maintenance

Releases, last 12 months
031 in total
Latest version
3.3.2, 19 Jul 20251 year ago
First published
19 Nov 2011
Last push to GitHub
24 Oct 2025336 days before the snapshot
Repository archived
No
Open issues
0
Open pull requests
0
Commits, last 52 weeks
1
Dependents on npm
635

Major versions

  1. v3 first release 3.0.1, 22 Feb 2015
  2. v2 first release 2.0.0, 26 Aug 2014
  3. v1 first release 1.0.0, 7 Aug 2014
  4. v0 first release 0.0.7, 20 Nov 2011

Recent releases

VersionPublished
3.3.219 Jul 2025
3.3.014 Dec 2018
3.2.127 Feb 2017
3.2.025 Oct 2016
3.1.019 Sept 2015
3.0.122 Feb 2015
2.2.16 Feb 2015
2.2.029 Nov 2014
2.1.021 Oct 2014
2.0.25 Oct 2014
2.0.12 Sept 2014
2.0.026 Aug 2014
1.1.022 Aug 2014
1.0.07 Aug 2014

Compatibility

Module format
CommonJSFrom package.json type, main and exports fields
TypeScript types
None
Node.js engine range
>= 0.4
Runtimes
-
Unpacked size (npm)
56 kB
Dependencies (0)
None

Install

npm install is

CDN

  • jsDelivrhttps://cdn.jsdelivr.net/npm/is@3.3.2/
  • unpkghttps://unpkg.com/is@3.3.2/
  • esm.shhttps://esm.sh/is@3.3.2
Sources: npm registry, npm downloads API, GitHub API. Data fetched 25 Sept 2026.

Indexability: Indexed.