Multi-Step Form With Retained Draft

Repository Boundary

Retain entered values across steps and guard progression and final submission. This is a consumer interaction composition in Design Engineering. Spatial structure comes from Form Flow; this recipe adds no reusable Layout behavior.

Reusable Method

Selected Pattern Stack

single owner, draft/baseline, submitted snapshot, unsaved navigation.

Ownership And Event Flow

The flow owns all field values and current step; each field emits intents. Validity is derived from relevant fields. The final operation owns the submitted snapshot. Unmounting a step does not destroy the flow draft.

Edit → validate current step → advance if allowed. Back preserves values. Changing an earlier answer recomputes eligibility and invalidates dependent values under an explicit policy. Final Submit captures the whole valid draft once.

Composition And Substitution

An in-memory step is enough when deep links are not a requirement; use URL state when they are. Versioned restore is optional for long flows and requires retention/privacy decisions. Do not persist request-pending flags.

Acceptance Sequences

Sequence	Expected outcome
Advance, go Back, revisit	Values persist; errors follow current validity
Change an earlier branching answer	Hidden dependent answers are cleared or excluded under declared policy
Deep-link to a later step	Guard prerequisites or redirect without silently submitting
Fail final submission	Retain all fields and provide a route to the relevant error
Edit while final save completes	Preserve later edits using snapshot semantics

Opinionated Guidance

Keep the ownership boundaries visible when composing the patterns. One screen can combine these mechanisms without making every value global. Record the rejected alternative and its user-visible cost in the state brief.

Platform-Specific Guidance

Announce step context and move focus to the step heading or first invalid field as appropriate. Step order, DOM order, and validation routes must agree.

Unsupported Absolutes

These acceptance sequences are proposed integration checks, not captured product evidence. Pattern model tests do not prove this entire screen, its backend, or its focus behavior.

Verification Contract

Adapt every acceptance row to the consumer and record actual results with the verification matrix. Include the ordinary successful task and at least one interrupted task. The initial handoff is consumer_reference: not_applicable because this fictional recipe selects no consumer profile or conformance record.

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.