Before reaching for a library.
WHAT KINDS OF STATE EXIST
Local, belonging to one component Shared, needed by several Server data, fetched and cached Address state, reflected in the URL Form state
WHY THAT DISTINCTION MATTERS
They have different requirements, and one tool rarely suits all.
WHAT TO KEEP LOCAL
Anything only one component needs.
WHAT TO LIFT
State needed by a component and its siblings, to their common ancestor.
WHAT CONTEXT OR PROVIDE FACILITIES SOLVE
Passing values deeply without threading them through every level.
WHAT THEY DO NOT SOLVE
Frequent updates, which re-render everything consuming them.
WHAT ADDRESS STATE PROVIDES
State that can be shared, bookmarked and returned to.
WHAT BELONGS THERE
Filters, search terms, pagination, selected tabs.
WHY
Because users expect to be able to share a link to what they are looking at.
WHAT MOST APPLICATIONS DISCOVER
That most of what they put in a global store was server data or address state.
WHAT TO ASK BEFORE ADDING A STATE LIBRARY
What genuinely needs to be shared, and how often it changes.
