Comparing objects in JavaScript

Question

I have this code:

var object1 = {same:'test'}
var object2 = {same:'test'};       
console.log(object1 === object2)

It returns false in the console.

I also have this code:

var object1 = {same:'test'}
var object2 = object1;
console.log(object1 === object2)  

It returns true in the console.

I know '===' is an equality operator, but I don't know how it works on objects.

Why does the first example return false?

Answer 1

See this ball? Its colour is red. Call it ball1.

See this ball? Its colour is red. Call it ball2.

Is ball1 the same object as ball2? No, they are distinct objects that happen to have identical properties.

---

See this ball? Its colour is red. Call it ball1.

Let's call ball1, ball2.

Is ball1 the same object as ball2? Yes. They are the same ball.

Answer 2

Objects are compared by reference equality, and since object1 and object2 are two distinct instances, they are different objects (think of it as: they occupy different places in memory).

If however you assign object1 to object2, they both point to the same place in memory and thus are equal (they are two references to the same single object, it only exists once in memory). Changing a property through object1.same = 'uiae'; will update the property object2.same as well (because they are in fact the same identical object and the same property)

Answer 3

var object1 ={same:'test'}
var object2 ={same:'test'};       
console.log(object1 === object2)

In this case you are creating two different objects. that's why it returns false value in console when checking with === operator.

var object1 ={same:'test'}
var object2 =object1;
console.log(object1 === object2)

In this case you are creating one object and object1 & object2 referencing to created object, that's why it returns true when you are checking with === operator.

In second case if we change the object2["same"]="test2" then object1["same"] value also be changes to test2.

In first case it won't happens like that, because object1 & object2 are two different objects.

refer this: Object Equality in JavaScript

hopes this is may be helpful.