# is-weakref [![Version Badge][npm-version-svg]][package-url] [![github actions][actions-image]][actions-url] [![coverage][codecov-image]][codecov-url] [![dependency status][deps-svg]][deps-url] [![dev dependency status][dev-deps-svg]][dev-deps-url] [![License][license-image]][license-url] [![Downloads][downloads-image]][downloads-url] [![npm badge][11]][1] Is this value a JS WeakRef? This module works cross-realm/iframe, and despite ES6 @@toStringTag. ## Example ```js var isWeakRef = require('is-weakref'); assert(!isWeakRef(function () {})); assert(!isWeakRef(null)); assert(!isWeakRef(function* () { yield 42; return Infinity; }); assert(!isWeakRef(Symbol('foo'))); assert(!isWeakRef(1n)); assert(!isWeakRef(Object(1n))); assert(!isWeakRef(new Set())); assert(!isWeakRef(new WeakSet())); assert(!isWeakRef(new Map())); assert(!isWeakRef(new WeakMap())); assert(isWeakRef(new WeakRef({}))); class MyWeakRef extends WeakRef {} assert(isWeakRef(new MyWeakRef({}))); ``` ## Tests Simply clone the repo, `npm install`, and run `npm test` [package-url]: https://npmjs.org/package/is-weakref [npm-version-svg]: https://versionbadg.es/inspect-js/is-weakref.svg [deps-svg]: https://david-dm.org/inspect-js/is-weakref.svg [deps-url]: https://david-dm.org/inspect-js/is-weakref [dev-deps-svg]: https://david-dm.org/inspect-js/is-weakref/dev-status.svg [dev-deps-url]: https://david-dm.org/inspect-js/is-weakref#info=devDependencies [license-image]: https://img.shields.io/npm/l/is-weakref.svg [license-url]: LICENSE [downloads-image]: https://img.shields.io/npm/dm/is-weakref.svg [downloads-url]: https://npm-stat.com/charts.html?package=is-weakref [codecov-image]: https://codecov.io/gh/inspect-js/is-weakref/branch/main/graphs/badge.svg [codecov-url]: https://app.codecov.io/gh/inspect-js/is-weakref/ [actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/inspect-js/is-weakref [actions-url]: https://github.com/inspect-js/is-weakref/actions