At the recent Polymer Summit (London, 2016), there was a lot of talk about being lazy (as in lazy loading). This means that you are only loading / rendering what you need and (at best) nothing more.
This suggests that the short answer to your question is: The element newshould save the data on its own, as this is the most suitable place for this.
As for the long answer, carry me for a while.
On the Google Developer Web Fundamentals page , there is actually an architectural template called Application Shell Model . This template actually describes your element my-main-task.
Some useful quotes:
"shell" - HTML, CSS JavaScript, /.../
/.../ , , .
( my-main-task).
, (Github repo, -).
"app shell" shop-app ( ), , :
, , -.
, Checkout, shop-checkout ( ). , (.. ) , .
shop-list ( ). , , , .
, Shop, . (Youtube video) , : , , . ( ) , ( ) . , .