[Tests] use shared travis-ci configs 8674582
[Tests] migrate tests to Github Actions dff6643
[meta] do not publish github action workflow files b26112a
[meta] make auto-changelog config consistent 8d10175
[readme] fix repo URLs, remove defunct badges ab8db24
[Tests] run nyc on all tests; use tape runner 7d084df
[Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, object-inspect, tape 576f6f3
[actions] add automatic rebasing / merge commit blocking 97efa53
[actions] add "Allow Edits" workflow fb1b4f7
[Dev Deps] update eslint, @ljharb/eslint-config, has-symbols, object-inspect, safe-publish-latest 1e03c61
[Deps] update is-boolean-object, is-number-object, is-string, is-symbol 13673df
[Dev Deps] update auto-changelog, in-publish, tape 65a0e15
[Dev Deps] update eslint, @ljharb/eslint-config, tape f8a0afe
[Deps] update is-bigint, is-boolean-object e7a1ce2
[actions] switch Automatic Rebase workflow to pull_request_target event e46f193
[Dev Deps] update @ljharb/eslint-config, tape df3da14
[Dev Deps] update auto-changelog; add aud e2e8a12
[meta] add funding field 7df404b
[Dev Deps] update auto-changelog 0d6b76d
[Tests] only audit prod deps 246151c
[meta] fix changelog c2d1685
[readme] Fix spelling error 25fb2b5

Readme

Source

which-boxed-primitive

Which kind of boxed JS primitive is this? This module works cross-realm/iframe, does not depend on instanceof or mutable properties, and works despite ES6 Symbol.toStringTag.

Example

var whichBoxedPrimitive = require('which-boxed-primitive');
var assert = require('assert');

// unboxed primitives return `null`
// boxed primitives return the builtin constructor name

assert.equal(whichBoxedPrimitive(undefined), null);
assert.equal(whichBoxedPrimitive(null), null);

assert.equal(whichBoxedPrimitive(false), null);
assert.equal(whichBoxedPrimitive(true), null);
assert.equal(whichBoxedPrimitive(new Boolean(false)), 'Boolean');
assert.equal(whichBoxedPrimitive(new Boolean(true)), 'Boolean');

assert.equal(whichBoxedPrimitive(42), null);
assert.equal(whichBoxedPrimitive(NaN), null);
assert.equal(whichBoxedPrimitive(Infinity), null);
assert.equal(whichBoxedPrimitive(new Number(42)), 'Number');
assert.equal(whichBoxedPrimitive(new Number(NaN)), 'Number');
assert.equal(whichBoxedPrimitive(new Number(Infinity)), 'Number');

assert.equal(whichBoxedPrimitive(''), null);
assert.equal(whichBoxedPrimitive('foo'), null);
assert.equal(whichBoxedPrimitive(new String('')), 'String');
assert.equal(whichBoxedPrimitive(new String('foo')), 'String');

assert.equal(whichBoxedPrimitive(Symbol()), null);
assert.equal(whichBoxedPrimitive(Object(Symbol()), 'Symbol');

assert.equal(whichBoxedPrimitive(42n), null);
assert.equal(whichBoxedPrimitive(Object(42n), 'BigInt');

// non-boxed-primitive objects return `undefined`
assert.equal(whichBoxedPrimitive([]), undefined);
assert.equal(whichBoxedPrimitive({}), undefined);
assert.equal(whichBoxedPrimitive(/a/g), undefined);
assert.equal(whichBoxedPrimitive(new RegExp('a', 'g')), undefined);
assert.equal(whichBoxedPrimitive(new Date()), undefined);
assert.equal(whichBoxedPrimitive(function () {}), undefined);
assert.equal(whichBoxedPrimitive(function* () {}), undefined);
assert.equal(whichBoxedPrimitive(x => x * x), undefined);
assert.equal(whichBoxedPrimitive([]), undefined);

Tests

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

Keywords

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Last updated on 14 Dec 2020

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