Replace a one javascript object with another object

On page load I am creating two Javascript Objects, objDemo1 and objDemo1Backup where the latter is simply an exact copy of the first.

e.g.

objDemo1 { 
    sub_1 = { something: 123, somethingElse: 321 },
    sub_2 = { something: 456, somethingElse: 654 }
}

I can modify the values in sub_ as well as add / delete new sub_'s but the only object I am editing is objDemo1. i.e. I never change objDemo1Backup

I have a reset button that when clicked will reset objDemo1 back to what it was when the page originally loaded (i.e. objDemo1 = objDemo1Backup). This is where I am having the issue..

How do I set objDemo1 to objDemo1Backup?

I have tried:

objDemo1 = objDemo1Backup;

and

objDemo1 = null;
var objDemo1 = objDemo1Backup;

...as well as similar variations but nothing seems to work. Any ideas?

• Note: I can confirm that at the point of resetting, objDemo1Backup is exactly the same as it was when I created it and objDemo1 has changed.
• My code is definetly hitting the "reset" functionality, where I've tried the objDemo1 = objDemo1Backup... I just cannot figure out the syntax to replace the object.