is-negative-zero

What is is-negative-zero?

The is-negative-zero npm package is a utility that provides a simple function to check if a given number is -0. In JavaScript, -0 and +0 are considered distinct values (due to IEEE 754 floating point), and this package helps in identifying if a number is specifically -0.

What are is-negative-zero's main functionalities?

Check if a number is -0

This feature allows you to check if a given number is exactly -0. It returns true if the number is -0, and false otherwise. This can be particularly useful in mathematical computations and graphics programming where the distinction between -0 and +0 can have implications.

const isNegativeZero = require('is-negative-zero');

console.log(isNegativeZero(-0)); // true
console.log(isNegativeZero(0)); // false
console.log(isNegativeZero(-1)); // false

Other packages similar to is-negative-zero

is-zero

Similar to is-negative-zero, is-zero is a utility for checking if a number is 0. However, it does not distinguish between -0 and +0, making it less specific for cases where the sign of zero matters.

lodash.isequal

While not specifically designed for checking -0, lodash's isEqual function can accurately compare -0 and +0, among many other complex equality checks. It's more versatile but also much larger and more complex than is-negative-zero, which is focused solely on the -0 check.

README

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