Mystery behind JS Object Equality ( === )

Lets us understand the mystery

Equality operators (== or ===) both work differently for objects (Type of array is an object in JS ) when compared to other primitive types.

const a = "Erode";
const b = "Erode";

console.log(a == b) //true
console.log(a === b) //true 
console.log("Erode" === "Erode") //true
console.log("Erode" == "Erode") //true

As expected every comparisions ends up with true

const a = {city:"Erode"};
const b = {city:"Erode"};

console.log(a == b) //false
console.log(a === b) //false

console.log(a == a) //true
console.log(a === a) //true

console.log(b == b) //true
console.log(b === b) //true

As you can see same properties and same values is not equal objects

As mentioned earlier, we are actually comparing the references not values, incase of object

typeof {city:”Erode”} — object

typeof 1 — number

So be careful when you are comparing object and (array) in javascript.

So how to compare the values of the objects

If order of the elements should be matched, we can compare by converting to string

JSON.stringify(a) === JSON.stringify(b)

If elements can be of any order in both the arrays, we can do the following

Object.entries(a).sort().toString()===Object.entries(b).sort().toString()

Convert to an array, sort and then convert to string, compare it, or if u r using packages like lodash, u can use _isEqual