which-boxed-primitive
Advanced tools
Which kind of boxed JS primitive is this?
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Changelog
v1.0.2 - 2020-12-14
8674582
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b26112a
auto-changelog
config consistent 8d10175
ab8db24
nyc
on all tests; use tape
runner 7d084df
eslint
, @ljharb/eslint-config
, aud
, auto-changelog
, object-inspect
, tape
576f6f3
97efa53
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eslint
, @ljharb/eslint-config
, has-symbols
, object-inspect
, safe-publish-latest
1e03c61
is-boolean-object
, is-number-object
, is-string
, is-symbol
13673df
auto-changelog
, in-publish
, tape
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eslint
, @ljharb/eslint-config
, tape
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is-bigint
, is-boolean-object
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pull_request_target
event e46f193
@ljharb/eslint-config
, tape
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auto-changelog
; add aud
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auto-changelog
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Readme
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.
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);
Simply clone the repo, npm install
, and run npm test
Which kind of boxed JS primitive is this?
The npm package which-boxed-primitive receives a total of 17,841,093 weekly downloads. As such, which-boxed-primitive popularity was classified as popular.
We found that which-boxed-primitive demonstrated a not healthy version release cadence and project activity. It has 1 open source maintainer collaborating on the project.