object-is

What is object-is?

The 'object-is' npm package provides a utility function for comparing two values, determining if they are the same value. This is particularly useful for edge cases in JavaScript comparisons, such as NaN, +0, and -0, where traditional equality checks (== or ===) might fail or not behave as expected.

What are object-is's main functionalities?

Exact equality comparison

This feature allows for the comparison of two values to determine if they are exactly the same, including more accurate handling of special JavaScript cases like NaN and +/-0.

const objectIs = require('object-is');
console.log(objectIs('foo', 'foo')); // true
console.log(objectIs(window, window)); // true
console.log(objectIs('foo', 'bar')); // false
console.log(objectIs(0, -0)); // false
console.log(objectIs(NaN, NaN)); // true

Other packages similar to object-is

is-equal

A package that offers deep equality comparison. Unlike 'object-is', which only checks if two values are the same, 'is-equal' can compare objects and arrays deeply, making it suitable for more complex data structures.

deep-equal

This package also provides deep equality checks, similar to 'is-equal'. It compares the contents of objects and arrays recursively, which is more comprehensive than the simple value comparison provided by 'object-is'.

README

#object-is

ES2015-compliant shim for Object.is - differentiates between -0 and +0, and can compare to NaN.

Essentially, Object.is returns the same value as === - but true for NaN, and false for -0 and +0.

Example

Object.is = require('object-is');
var assert = require('assert');

assert.ok(Object.is());
assert.ok(Object.is(undefined));
assert.ok(Object.is(undefined, undefined));
assert.ok(Object.is(null, null));
assert.ok(Object.is(true, true));
assert.ok(Object.is(false, false));
assert.ok(Object.is('foo', 'foo'));

var arr = [1, 2];
assert.ok(Object.is(arr, arr));
assert.notOk(Object.is(arr, [1, 2]));

assert.ok(Object.is(0, 0));
assert.ok(Object.is(-0, -0));
assert.notOk(Object.is(0, -0));

assert.ok(Object.is(NaN, NaN));
assert.ok(Object.is(Infinity, Infinity));
assert.ok(Object.is(-Infinity, -Infinity));

Tests

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

Changelog

v1.1.4 - 2020-11-26

Commits

• [Tests] migrate tests to Github Actions 958ab26
• [Tests] add shimmed and implementation and index tests; run es-shim-api in postlint; use tape runner b918fb8
• [Tests] run nyc on all tests 8f62816
• [actions] add "Allow Edits" workflow aa419f0
• [Deps] use call-bind instead of es-abstract 4991728
• [Dev Deps] update eslint, @ljharb/eslint-config, aud 3ce2ef5
• [meta] ignore coverage output d778383
• [actions] switch Automatic Rebase workflow to pull_request_target event e0d9b41