Object inside an array keep the old obj reference after changing obj value

could someone please explain me this:

let obj = {name: 'puki'}
const arr = [obj]
arr[0] === obj // true (same ref address)
obj = null
console.log(arr) // [{name: 'puki'}]

how come the array is keeping the old obj ref?

Answer

You are confusing an object reference and the object itself.

In your code obj is a reference (an address) to the actual object {name: 'puki'}

The array also stores the reference (the address) to the actual object.

When you overwrite the reference obj with null you’re not actually modifying the actual object {name: 'puki'} or the target of the address, you’re just overwriting the reference (pointer) with the null pointer / value. There is no dereferencing in Javascript like it exists in C / C++