which-collection

which-collection

Which kind of Collection (Map, Set, WeakMap, WeakSet) is this JavaScript value? Works cross-realm, without instanceof, and despite Symbol.toStringTag.

Example

var whichCollection = require('which-collection');
var assert = require('assert');

assert.equal(false, whichCollection(undefined));
assert.equal(false, whichCollection(null));
assert.equal(false, whichCollection(false));
assert.equal(false, whichCollection(true));
assert.equal(false, whichCollection([]));
assert.equal(false, whichCollection({}));
assert.equal(false, whichCollection(/a/g));
assert.equal(false, whichCollection(new RegExp('a', 'g')));
assert.equal(false, whichCollection(new Date()));
assert.equal(false, whichCollection(42));
assert.equal(false, whichCollection(NaN));
assert.equal(false, whichCollection(Infinity));
assert.equal(false, whichCollection(new Number(42)));
assert.equal(false, whichCollection(42n));
assert.equal(false, whichCollection(Object(42n)));
assert.equal(false, whichCollection('foo'));
assert.equal(false, whichCollection(Object('foo')));
assert.equal(false, whichCollection(function () {}));
assert.equal(false, whichCollection(function* () {}));
assert.equal(false, whichCollection(x => x * x));
assert.equal(false, whichCollection([]));

assert.equal('Map', whichCollection(new Map()));
assert.equal('Set', whichCollection(new Set()));
assert.equal('WeakMap', whichCollection(new WeakMap()));
assert.equal('WeakSet', whichCollection(new WeakSet()));

Tests

Simply clone the repo, npm install, and run npm test

Changelog

v1.0.2 - 2024-03-08

Commits

• [actions] reuse common workflows a5b2949
• [Tests] migrate tests to Github Actions 283ec03
• add types bf576db
• [actions] use node/install instead of node/run; use codecov action 24968a2
• [Dev Deps] update eslint, @ljharb/eslint-config, object-inspect, safe-publish-latest, tape f60b277
• [Tests] run nyc on all tests 5700269
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, object-inspect, tape eb1f1a4
• [actions] remove redundant finisher cd5b8fc
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, object-inspect, tape f5786fa
• [actions] update rebase action to use reusable workflow 7ac7b67
• [actions] update codecov uploader b074105
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, object-inspect, tape ec640d6
• [actions] add "Allow Edits" workflow 65d842e
• [readme] remove travis badge f106289
• [Dev Deps] update @ljharb/eslint-config, aud, npmignore, object-inspect, tape e784a1f
• [meta] use npmignore to autogenerate an npmignore file 95b503f
• [readme] add actions and codecov badges 121ba2d
• [Deps] update is-map, is-set, is-weakmap, is-weakset 4aa150f
• [meta] simplify "exports" 2afaed7
• [Deps] update is-map, is-set ce44763
• [actions] switch Automatic Rease workflow to pull_request_target event b16b664
• [Dev Deps] update auto-changelog, tape 2b9c953
• [meta] add missing engines.node dcdbfde
• [Dev Deps] update auto-changelog; add aud 8e7f28d
• [meta] add sideEffects flag 3e0376b
• [Deps] update is-weakset 7b3e922
• [Tests] only audit prod deps 3339fea