---
phase: 06-renderer-architecture
plan: 01
subsystem: ui
tags: [typescript, d3, strategy-pattern, state-management]

requires:
  - phase: 01-05 (v1.0)
    provides: heatmap.ts monolith with all rendering logic
provides:
  - ModeRenderer interface and RenderContext type contracts
  - HeatmapState creation via createInitialState()
  - Renderer registry (registerRenderer/getRenderer)
  - Shared tooltip, color-scale, stats, date-utils modules
affects: [06-02, 06-03, 07-mode-renderers]

tech-stack:
  added: []
  patterns: [strategy-pattern renderer registry, state factory function, shared utility extraction]

key-files:
  created:
    - assets/src/state.ts
    - assets/src/renderers/types.ts
    - assets/src/renderers/registry.ts
    - assets/src/shared/tooltip.ts
    - assets/src/shared/color-scale.ts
    - assets/src/shared/stats.ts
    - assets/src/shared/date-utils.ts
    - assets/test/state.test.ts
    - assets/test/registry.test.ts
    - assets/test/tooltip.test.ts
    - assets/test/color-scale.test.ts
    - assets/test/date-utils.test.ts
  modified:
    - assets/src/types.ts

key-decisions:
  - "clearRegistry() exported for test isolation of module-level Map"
  - "Tooltip consolidated: createTooltip now appends to body and sets fixed positioning (was scattered inline in heatmap.ts)"
  - "FALLBACK_COLORS used directly in color-scale, resolveColors() dropped (always returned same value)"

patterns-established:
  - "Strategy pattern: ModeRenderer interface with mode string key, render(ctx), optional destroy()"
  - "State factory: plain interface + createInitialState() function, no class"
  - "Shared utilities: pure functions extracted to assets/src/shared/ with independent tests"

requirements-completed: []

duration: 2min
completed: 2026-04-09
---

# Phase 6 Plan 01: Foundation Modules Summary

**Strategy-pattern renderer contracts, state factory, registry, and 4 shared utility modules extracted from heatmap.ts monolith**

## Performance

- **Duration:** 2 min
- **Started:** 2026-04-09T07:31:40Z
- **Completed:** 2026-04-09T07:34:36Z
- **Tasks:** 2
- **Files modified:** 13

## Accomplishments
- Created ModeRenderer/RenderContext type contracts for strategy-pattern rendering
- Built state module with HeatmapState interface and createInitialState() factory
- Built renderer registry with register/get/clear operations
- Extracted tooltip, color-scale, stats, and date-utils as standalone shared modules
- All 62 tests pass (20 new + 42 existing), esbuild still produces valid output

## Task Commits

Each task was committed atomically:

1. **Task 1: Create type contracts, state module, and renderer registry** - `fe24e8b` (feat)
2. **Task 2: Extract shared utilities from heatmap.ts** - `b9b2565` (feat)

## Files Created/Modified
- `assets/src/types.ts` - Added DisplayMetric, HeatmapMode, FilterState types
- `assets/src/state.ts` - HeatmapState interface and createInitialState() factory
- `assets/src/renderers/types.ts` - ModeRenderer and RenderContext interfaces
- `assets/src/renderers/registry.ts` - Renderer registration and lookup with clearRegistry()
- `assets/src/shared/tooltip.ts` - Consolidated tooltip create/show/hide functions
- `assets/src/shared/color-scale.ts` - buildColorScale with DisplayMetric support
- `assets/src/shared/stats.ts` - calculateStreak, calculateStats, renderStats
- `assets/src/shared/date-utils.ts` - buildDateMap, generateCells, getWeekInterval, DayCell
- `assets/test/state.test.ts` - 2 tests for state factory
- `assets/test/registry.test.ts` - 3 tests for registry
- `assets/test/tooltip.test.ts` - 5 tests for tooltip lifecycle
- `assets/test/color-scale.test.ts` - 4 tests for color scale
- `assets/test/date-utils.test.ts` - 6 tests for date utilities

## Decisions Made
- clearRegistry() exported from registry.ts for test isolation (module-level Map needs clearing between tests)
- Tooltip creation consolidated: new createTooltip() appends to body with fixed positioning (was scattered across multiple lines in heatmap.ts)
- resolveColors() dropped from color-scale module -- it always returned FALLBACK_COLORS

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
None.

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- All building blocks ready for Plan 02 to wire heatmap.ts to use shared modules
- ModeRenderer interface ready for year-mode renderer implementation
- State and registry ready for mode switching logic

## Self-Check: PASSED

- All 12 created files exist on disk
- Both task commits verified (fe24e8b, b9b2565)
- Full test suite: 62/62 passing
- esbuild: produces valid output

---
*Phase: 06-renderer-architecture*
*Completed: 2026-04-09*