The is-weakmap npm package is a utility that allows developers to check if a given value is a WeakMap. WeakMaps are collections of key/value pairs where the keys are weakly referenced, meaning they can be garbage collected if there is no other reference to the object. This package provides a straightforward way to determine if an object is an instance of a WeakMap, which can be useful in various programming scenarios where type checking is necessary.

What are is-weakmap's main functionalities?

Checking if a value is a WeakMap

This feature allows developers to check if a given value is an instance of WeakMap. The function returns true if the value is a WeakMap, and false otherwise. This can be particularly useful when working with data structures and ensuring that certain operations or functions are only applied to WeakMaps.

const isWeakMap = require('is-weakmap');

const wm = new WeakMap();
console.log(isWeakMap(wm)); // true

const obj = {};
console.log(isWeakMap(obj)); // false

Other packages similar to is-weakmap

Changelog

Source

v2.0.2 - 2024-03-08

Commits

[actions] reuse common workflows 0af1292
[Tests] migrate tests to Github Actions f35679b
[actions] use node/install instead of node/run; use codecov action cd2f0fa
add types 6e28e6a
[Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, es6-shim, object-inspect, tape 95815ce
[readme] update URLs 2c4eb0b
[Tests] run nyc on all tests; use tape runner 0a45b37
[Dev Deps] update eslint, @ljharb/eslint-config, object-inspect, safe-publish-latest, tape ffe9459
[Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, es5-shim, object-inspect, tape c3c2f11
[actions] remove redundant finisher afa4018
[Dev Deps] update eslint, @ljharb/eslint-config, auto-changelog, core-js, es5-shim, object-inspect, safe-publish-latest, tape 3f22fc1
[Dev Deps] update @ljharb/eslint-config, aud, es6-shim, npmignore, object-inspect, tape 84ba754
[actions] update rebase action to use reusable workflow def85cb
[actions] update codecov uploader 659031e
[actions] add "Allow Edits" workflow a916e89
[readme] remove travis badge 01d0c7d
[Dev Deps] update eslint, @ljharb/eslint-config, aud, object-inspect, tape ad90d06
[meta] use npmignore to autogenerate an npmignore file 8b0b44f
[Dev Deps] update eslint, @ljharb/eslint-config, es5-shim, tape 9d8a683
[Tests] add core-js tests 8ba8d2b
[readme] add actions and codecov badges 49769ce
[Dev Deps] update eslint, @ljharb/eslint-config, tape 377dfac
[actions] switch Automatic Rease workflow to pull_request_target event 00f8c17
[Dev Deps] update es5-shim, tape 3a82ee8
[meta] add missing engines.node 3671b4f
[meta] use prepublishOnly script for npm 7+ 2a5d5ea
[Dev Deps] update auto-changelog; add aud 595583b
[readme] remove dead badges 4d6cb2c
[Tests] run all tests on npm test 9da2487
[Tests] only audit prod deps 2f9281a
[meta] add sideEffects flag b9c8797

Readme

Source

is-weakmap

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

Example

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

Keywords

FAQs

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Last updated on 08 Mar 2024

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