Issue title: How to maintain a viewModel through pages and again come back to it?
 Issue body: Hey

I am trying to build a shopping cart through Nativescript. 
How can I maintain a cart viewModel so that I can store and update my cart constantly through all pages. 
Also, when I return back from a page with the back button, the pages appears fine but the functionality is disrupted. 

Also, how can I put a load more option in list page.

Hoping for some prompt solutions. 
Thanks
 Comments: 
 Comment 0: I believe you are going to need some local data storage. NativeScript provides the app_settings module and there is a SqlLite plugin. I would use app_settings and just JSON.stringify(dataObject) when you navigate away from the page and then JSON.parse(dataObject) when you go back to the page. 

Another approach, if not dealing with a deep navigational hierarchy, would be to show the secondary page as a modal 
 Comment 1: Thanks. Local storage solution with app_settings module worked. 

But still stuck with "load more" option.?
 Comment 2: Done with that. 

Thanks a lot.
 Comment 3: This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
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