Equality for two JavaScript objects

Comparing two JavaScript objects for equality involves checking if they have the same properties with the same values. This process is more complex than comparing primitive values due to the objects' reference-based nature and potential nested structures in JavaScript.

Below are the approaches to check the equality of two JavaScript objects:

Using a Strict equality operator

The strict equals (===) operator compares memory locations in case of comparing objects.

Example: To demonstrate comparing the equality of the two JavaScript objects using the strict equality operator in JavaScript.

object1 = {
    name: "GeeksForGeeks",
    founder: "SandeepJain",
};

object2 = {
    name: "GeeksForGeeks",
    founder: "SandeepJain",
};
check = object1 === object2;
// Nikunj Sonigara
console.log("Does Object1 " + "equals Object2 ? : " + check);
object1 = object2;

check = object1 === object2;

console.log("Does Object1 equals" + " Object2 ? : " + check);

Does Object1 equals Object2 ? : false
Does Object1 equals Object2 ? : true

Using the Object.is method

Object.is is similar to the strict equality operator (===) but treats NaN as equal to NaN and -0 not equal to 0.

Example: To demonstrate checking the equality of the two JavaScript objects.

const obj1 = { a: 1 };
const obj2 = { a: 1 };

console.log(Object.is(obj1, obj2));

false

Comparing JSON Strings

This method involves converting objects to JSON strings and comparing the strings. It works well for simple, non-circular objects.

Example: To demonstrate checking the equality of two JavaScript objects by converting the Objects to JSON strings.

const obj1 = { a: 1, b: 2 };
const obj2 = { a: 1, b: 2 };

const isEqual = JSON.stringify(obj1) === JSON.stringify(obj2);
console.log(isEqual);

true

Using Lodash's _.isEqual Method

Lodash's _.isEqual method can be used to compare two objects for deep equality. This method simplifies the comparison process and handles nested objects efficiently.

const _ = require('lodash');

const obj1 = { a: 1, b: { c: 2 } };
const obj2 = { a: 1, b: { c: 2 } };
const obj3 = { a: 1, b: { c: 3 } };

console.log(_.isEqual(obj1, obj2));
console.log(_.isEqual(obj1, obj3));

Output:

true
false