# arasatasaygin/is.js

Micro check library

Repository: https://github.com/arasatasaygin/is.js
Canonical: https://ross.abutalabs.com/products/isjs
Homepage: http://is.js.org
Language: JavaScript
License: MIT
License Family: permissive
Last push: 2022-01-11T17:39:48+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4262, "days_push": 1695, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 9066, forks 615 (observed 2026-08-28T04:10:28.219492+00:00)

## What it is
is.js is a general-purpose, dependency-free JavaScript micro check library for validating types, regexps, presence, time, and environment. It works in Node.js and the browser and provides not/all/any interfaces for its checks.

## Use cases
- validate value types in javascript
- check if a string is a valid email or url
- detect browser and device environment
- check date properties like leap year or weekend
- validate phone numbers and zip codes

## When to choose
- you need lightweight, zero-dependency runtime type and value checks
- you want a single library covering types, regexps, time, and environment detection
- you need checks that work in both Node.js and the browser

## When to avoid
- you need static type checking rather than runtime checks
- you want a library with recent active development or new features
- you need schema or object-shape validation rather than simple checks

## Facets
- artifact type: library
- maturity: maintenance
- function: developer-tools, form-handling
- domain: web-development, developer-tools
- platform: browser, cross-platform
- tags: type-checking, validation, micro-library, zero-dependency, javascript, nodejs

## Member repositories
- arasatasaygin/is.js (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:28.219492+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:24:01.767663+00:00, confidence not recorded.
  - readme: https://github.com/arasatasaygin/is.js (fetched 2026-08-28T04:10:28.219492+00:00, sha 6c55b5f8cc02)
  - homepage: http://is.js.org (fetched 2026-08-29T08:24:12.439941+00:00, sha 09bca95790ed)
- Data as of 2026-08-30T08:39:29.467469+00:00.