# is-weakmap

> Is this value a JS WeakMap? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

Latest version **2.0.2** (published 2024-03-08) · MIT license · 0 weekly downloads

## Install

```sh
npm install is-weakmap
pnpm add is-weakmap
yarn add is-weakmap
bun add is-weakmap
```

## Health

**Score 35/100 (D)** — status: abandoned.

Positive: has types; no vulnerabilities; high quality score.

Warnings: low downloads; no esm support.

Negative: abandoned.

## Facts

| | |
|---|---|
| Version | 2.0.2 |
| Published | 2024-03-08 |
| First published | 2015-02-18 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | CommonJS |
| Node | >= 0.4 |
| Dependencies | 0 |
| Unpacked size | 20.1 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 3 |
| Author | Jordan Harband |
| Maintainers | ljharb |
| Keywords | map, weakmap, set, weakset, collection, is, robust |

## Links

- npm: https://www.npmjs.com/package/is-weakmap
- Repository: https://github.com/inspect-js/is-weakmap
- Homepage: https://github.com/inspect-js/is-weakmap#readme
- Issues: https://github.com/inspect-js/is-weakmap/issues
- Funding: https://github.com/sponsors/ljharb
- npm.io page: https://npm.io/package/is-weakmap

## Alternatives

- [memory-cache](https://npm.io/package/memory-cache.md) — 795.0K weekly downloads
- [@httptoolkit/proxy-agent](https://npm.io/package/@httptoolkit/proxy-agent.md) — 11.2K weekly downloads
- [express-cache-controller](https://npm.io/package/express-cache-controller.md) — 5.3K weekly downloads
- [http-cache-middleware](https://npm.io/package/http-cache-middleware.md) — 4.5K weekly downloads
- [cache2](https://npm.io/package/cache2.md) — 1.5K weekly downloads

## Recent versions

- 2.0.2 (latest) — 2024-03-08
- 2.0.1 — 2019-12-18
- 2.0.0 — 2019-11-12
- 1.0.1 — 2015-08-31
- 1.0.0 — 2015-02-18

## README

# is-weakmap <sup>[![Version Badge][npm-version-svg]][package-url]</sup>

[![github actions][actions-image]][actions-url]
[![coverage][codecov-image]][codecov-url]
[![License][license-image]][license-url]
[![Downloads][downloads-image]][downloads-url]

[![npm badge][npm-badge-png]][package-url]

Is this value a JS WeakMap? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

## Example

```js
var isWeakMap = require('is-weakmap');
assert(!isWeakMap(function () {}));
assert(!isWeakMap(null));
assert(!isWeakMap(function* () { yield 42; return Infinity; });
assert(!isWeakMap(Symbol('foo')));
assert(!isWeakMap(1n));
assert(!isWeakMap(Object(1n)));

assert(!isWeakMap(new Set()));
assert(!isWeakMap(new WeakSet()));
assert(!isWeakMap(new Map()));

assert(isWeakMap(new WeakMap()));

class MyWeakMap extends WeakMap {}
assert(isWeakMap(new MyWeakMap()));
```

## Tests
Simply clone the repo, `npm install`, and run `npm test`

[package-url]: https://npmjs.org/package/is-weakmap
[npm-version-svg]: https://versionbadg.es/inspect-js/is-weakmap.svg
[deps-svg]: https://david-dm.org/inspect-js/is-weakmap.svg
[deps-url]: https://david-dm.org/inspect-js/is-weakmap
[dev-deps-svg]: https://david-dm.org/inspect-js/is-weakmap/dev-status.svg
[dev-deps-url]: https://david-dm.org/inspect-js/is-weakmap#info=devDependencies
[npm-badge-png]: https://nodei.co/npm/is-weakmap.png?downloads=true&stars=true
[license-image]: https://img.shields.io/npm/l/is-weakmap.svg
[license-url]: LICENSE
[downloads-image]: https://img.shields.io/npm/dm/is-weakmap.svg
[downloads-url]: https://npm-stat.com/charts.html?package=is-weakmap
[codecov-image]: https://codecov.io/gh/inspect-js/is-weakmap/branch/main/graphs/badge.svg
[codecov-url]: https://app.codecov.io/gh/inspect-js/is-weakmap/
[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/inspect-js/is-weakmap
[actions-url]: https://github.com/inspect-js/is-weakmap/actions

---
_Source: https://npm.io/package/is-weakmap · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._