is-negative-zero 
Is this value negative zero? === will lie to you.
Example
var isNegativeZero = require('is-negative-zero');
var assert = require('assert');
assert.notOk(isNegativeZero(undefined));
assert.notOk(isNegativeZero(null));
assert.notOk(isNegativeZero(false));
assert.notOk(isNegativeZero(true));
assert.notOk(isNegativeZero(0));
assert.notOk(isNegativeZero(42));
assert.notOk(isNegativeZero(Infinity));
assert.notOk(isNegativeZero(-Infinity));
assert.notOk(isNegativeZero(NaN));
assert.notOk(isNegativeZero('foo'));
assert.notOk(isNegativeZero(function () {}));
assert.notOk(isNegativeZero([]));
assert.notOk(isNegativeZero({}));
assert.ok(isNegativeZero(-0));
Tests
Simply clone the repo, npm install
, and run npm test