Hi Ahmed,
Well this is not Angular specific.
As you can see auth is an array ([...]) which contains an associative array ({...}).
So I would say you can access to the userPass field with auth[0].userPass.
For typescript you can refer to
this doc.
If you don't make this effort you will waste your time and it will be really frustrating.
Another side effect is that people here will stop help you as they really can't learn Angular for you.
This is just an advice don't take it bad.
Regards,
Arnaud.