When fetch and how store firebase data

Ionic Framework ionic-v3
1

hi guys,

i have several page that need to fetch data from firebase. i can store all my data app in one object.

HOW
the best way is : store all data in one object or store data in several object (one object by page) ?

WHEN
the best way is : fetch data at app’ starting or fetch data when page’s loading?

thanks in advance