Will two objects/arrays in javascript == each other by coincidence?

Lets say I have array a.

var a = [1,2,3];


And then there is array b.

var b = [1,2,3];


Is there ANY possible chance that a == b will return true? Even if it is one in a million. (I know that normally a == b will be false, but I am wondering if there is a chance that it will be true.)

a == b

a == b

a

b

2 Answers
2

The relevant part of the spec is 11.9.3 The Abstract Equality Comparison Algorithm:

The comparison x == y, where x and y are values, produces true or false. Such a comparison is performed as follows:

x == y

x

y

true

false

(Emphasis mine.)

So the answer to your question is no. a == b only returns true if they are in fact the same object.

a == b

true

Is there ANY possible chance that a == b will return true? Even if it is one in a million.

Yes. Instead of just comparing using object/array, you turn both of them to string and compare.

let a = [1,2,3]
let b = [1,2,3]

console.log('array comparison:',a.toString() == b.toString())

let c = { key: 'someVal' }
let d = { key: 'someVal' }

console.log('object comparison:',c.toString() == d.toString())

However, you must understand that they are simply not equal as both array/object are shared by reference, not value!

array/object

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