familysync/.planning/phases/06-ux-polish/06-01-SUMMARY.md

phase, plan, subsystem, tags, dependency_graph, tech_stack, key_files, decisions, metrics

phase	plan	subsystem	tags	dependency_graph	tech_stack	key_files	decisions	metrics
06-ux-polish	01	pwa/lib	tdd date-math event-form d-04	requires provides affects computeNewTimedEnd (apps/pwa/src/lib/eventDateTime.ts) computeNewAllDayEnd (apps/pwa/src/lib/eventDateTime.ts) Plan 06-06 (EventForm wires these helpers into onChange handlers)	added patterns Local Date accessors (WR-05) getFullYear/getMonth/getDate/getHours/getMinutes — never toISOString().slice TDD RED→GREEN with Vitest in apps/pwa	created modified apps/pwa/src/lib/eventDateTime.ts apps/pwa/src/lib/eventDateTime.test.ts	WR-05 enforced all new date formatting uses local accessors; toISOString().slice banned for date strings Private helpers (localDateISO, localTimeHHMM, dateDiffDays, addDaysISO) added to eventDateTime.ts to support the two exports	duration_minutes completed_date tasks_completed files_changed 2 2026-06-10 2 2

Phase 06 Plan 01: End-Tracking Duration Math (D-04) Summary

One-liner: Pure duration-preservation helpers (computeNewTimedEnd + computeNewAllDayEnd) with 1h/same-day floor rules, TDD RED→GREEN in eventDateTime.ts.

Tasks Completed

Task	Name	Commit	Files
1 (RED)	Failing tests for computeNewTimedEnd / computeNewAllDayEnd	16cdbf3	eventDateTime.test.ts
2 (GREEN)	Implement the two end-tracking helpers	605f543	eventDateTime.ts

What Was Built

Two exported pure functions added to apps/pwa/src/lib/eventDateTime.ts:

• computeNewTimedEnd(newStartDate, newStartTime, oldStartDate, oldStartTime, oldEndDate, oldEndTime) — preserves a timed event's duration when the start moves. Returns { endDate: 'YYYY-MM-DD', endTime: 'HH:MM' }. If the old end was already behind the old start (stale state), floors to newStart + 1 hour.
• computeNewAllDayEnd(newStartDate, oldStartDate, oldEndDate) — preserves an all-day event's inclusive day-span when the start moves. Returns 'YYYY-MM-DD'. If the old span was negative (stale state), floors to 0 days (same day as newStart).

Four private helpers added to the same file: localDateISO, localTimeHHMM, dateDiffDays, addDaysISO. All use local Date accessors (WR-05 compliance).

Test Coverage

Six new unit tests in apps/pwa/src/lib/eventDateTime.test.ts:

Test	Behavior
preserves a 1-hour timed delta	old 09:00→10:00; new start 11:00 → new end 12:00
preserves a multi-day timed delta (26h)	old 08:00→+26h; new start same offset → correct
floors to 1h when old end was behind start	stale end → snaps to newStart+1h
preserves a 0-day span (single day all-day)	oldStart=oldEnd → newEnd=newStart
preserves a 3-day span	newEnd = newStart + 3 days
floors to same day when old end behind start	negative span → 0 → same day

Full suite: 166/166 tests pass. Pre-existing serializeEventDateTime / localWallClockToUtcIso tests unaffected.

TDD Gate Compliance

• RED commit (test(06-01): ...): 16cdbf3 — 6 tests failing with TypeError: computeNewTimedEnd is not a function
• GREEN commit (feat(06-01): ...): 605f543 — all 166 tests pass
• RED→GREEN order confirmed via git log

Deviations from Plan

None — plan executed exactly as written.

Threat Flags

None. Pure client-side date arithmetic on already-trusted local form state. No network boundary, no new attack surface. T-06-01 accepted per threat model.

Self-Check: PASSED

• apps/pwa/src/lib/eventDateTime.ts — FOUND (modified)
• apps/pwa/src/lib/eventDateTime.test.ts — FOUND (modified)
• Commit 16cdbf3 — FOUND (RED: test(06-01))
• Commit 605f543 — FOUND (GREEN: feat(06-01))
• computeNewTimedEnd export — FOUND in eventDateTime.ts
• computeNewAllDayEnd export — FOUND in eventDateTime.ts
• No toISOString().slice in helper code — CONFIRMED