Objects. How to get object key and nested object key?

Question

JavaScript

Hello, I have little experience in working with objects and arrays, but I hope I will explain the essence clearly ...
I receive a callback from the server that looks like this:

We need only the keys of the parent and child object. And is it possible to give names to the keys of the object and the child object?
For example, what would look like this:
{device_id:11841221:{ user_id: 11853024, user_id: 1183211, user_id: 12312123}}?

Answer 1

$json = json_decode($response, true);
the second argument of the method will immediately return you a dictionary instead of an object, with keys instead of object field names. You can loop through it as you like and do whatever you want with it.

Answer 2

Here, I once described a similar problem -