js-true-equals

The goal of this package is to get as close as possible to a perfect JS equality algorithm..

Usage

npm i true-equals

then

const { equals } = require('true-equals');
// later ...
const areTrulyEqual = equals(oneObject, anotherObject)

Overview

The equality algorithm is pretty smart and is aware of:

• Native JS types! This includes primitives, Array, Set, Map, boxed primitives, typed arrays, etc.
• Prototypes!
• Getters and setters! A getter is not considered equal to a computed value.
• Custom properties on native types! For instance: const ar = []; ar.my = 'prop'; console.assert(!equals(ar, [])).
• (Non-)enumerability, (non-)configurability, and/or (non-)writability of object properties! These will be respected.
• etc.

Details

• Basically works how you would expect
• However, the following may be of note:
• equals(NaN, NaN) === true
• equals(+0, -0) === true
• Prototypes are compared by identity, not structure
  • equals(Object.create({}), Object.create({})) === false
• For Proxy objects, all traps are ignored besides the following:
  • getPrototypeOf: objects are considered unequal if they have different prototypes
  • ownKeys: objects are considered unequal if they have different ownKeys (ignoring order)
  • getOwnPropertyDescriptor: objects are considered unequal if their descriptors differ for any property
    • The result of getOwnPropertyDescriptor on keys not in ownKeys is ignored
• Objects of type Function, Promise, WeakSet, or WeakMap will be compared via identity (===) due to JS limitations