Who should own the state value of an item?

Question

My flux app displays a list locations. When user clicks on a location, it becomes 'active'. There can be only one active location at a time.

Should the state of location be a property of the location itself (e.g. location.active) or should it be part of the global state, e.g. activeLocationId?

Answer 1

I have written several variations of the app. It became obvious that active is not a property of the item itself (location in this case), but is the property of the UI (activeLocationId).

Some benefits:

• Single source of truth (You will not end up accidentally with two active locations).
• It is not affected if new location list is loaded (This is regardless of wether the new list includes the active location or not).
• Makes it easy to find the active location ID.