XuelesszzZ 94af2b8e7b 6-30-5 1 éve
..
.github 94af2b8e7b 6-30-5 1 éve
test 94af2b8e7b 6-30-5 1 éve
.editorconfig 94af2b8e7b 6-30-5 1 éve
.eslintignore 94af2b8e7b 6-30-5 1 éve
.eslintrc 94af2b8e7b 6-30-5 1 éve
.nycrc 94af2b8e7b 6-30-5 1 éve
CHANGELOG.md 94af2b8e7b 6-30-5 1 éve
LICENSE 94af2b8e7b 6-30-5 1 éve
README.md 94af2b8e7b 6-30-5 1 éve
index.js 94af2b8e7b 6-30-5 1 éve
package.json 94af2b8e7b 6-30-5 1 éve

README.md

which-boxed-primitive Version Badge

dependency status dev dependency status License Downloads

npm badge

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