State Management Decision Tree

Repository Boundary

This route selects consumer behavior within Design Engineering. It does not choose a global store or redefine Layout patterns.

Reusable Method

Question	Route	Decision to record
Can the value be calculated from current inputs?	Derived state	Source inputs and equality/invalidation
Do several controls write one accepted value?	Single owner	Nearest surviving owner and intent API
Does selection change when rows reorder?	ID selection	Stable identity and missing-item policy
Must edits survive Cancel or a failed save?	Draft and baseline	Draft owner and baseline meaning
Can editing continue during saving?	Submitted snapshot	Captured data and acknowledgement identity
Can leaving discard work?	Unsaved navigation	Cancel, discard, and save-and-leave policy
Can replaceable reads finish out of order?	Latest request wins	Result acceptance identity
Can an operation be activated repeatedly?	Single flight	Share, ignore, queue, or replace
Should a change appear before acknowledgement?	Optimistic overlay	Rollback scope and uncertain outcome recovery
Should Back, reload, and links restore the view?	URL state	Committed route versus input buffer
Is the screen reused for another identity?	Identity reset	Generation and cleanup scope
Must state survive a new session?	Versioned restore	Schema, account scope, migration and retention

These questions can select several patterns. For search, first separate the input buffer from the committed URL, then attach a latest-wins request owner and selected ID. The search recipe defines the joint contract.

Before adding another pattern, name a failure the existing set cannot express. Put a new combination in a recipe; add a primitive only when its owner or invariant is independently reusable.

Opinionated Guidance

Choose the failure and lifetime before the library. A cache, URL, form buffer, and session preference may share a screen without sharing an owner.

Platform-Specific Guidance

Transport cancellation, router guards, and storage hooks vary by framework and runtime. Record those adapter choices in the brief instead of assuming the abstract model implements them.

Unsupported Absolutes

A decision tree is not an exhaustive treatment of offline replication, collaboration, or server transactions. Escalate those requirements to a separately specified consistency protocol.

Verification Contract

Try routing a stale search result, lost edit, and wrong-account restore. Each must reach a named pattern and concrete failure trace. Revisit when two routes prescribe conflicting owners.

Source, License, And Attribution

Locally authored synthesis and examples. No upstream implementation is copied. These experimental contracts describe consumer-owned behavior; review when a failure, ownership change, or platform change invalidates an assumption.

IA Navigation

Parent: State Management. Next: Continue the state management route.