---
phase: 31-selector-optimization
verified: 2026-03-05T14:30:00Z
status: passed
score: 3/3 must-haves verified
---

# Phase 31: Selector Optimization Verification Report

**Phase Goal:** Redux selectors compute efficiently with memoization
**Verified:** 2026-03-05T14:30:00Z
**Status:** passed
**Re-verification:** No - initial verification

## Goal Achievement

### Observable Truths

| # | Truth | Status | Evidence |
|---|-------|--------|----------|
| 1 | Single mixer field change triggers 1-3 selector runs instead of 18+ | VERIFIED | useMixerHelper now uses 6 composed selectors (lines 59-64) with createSelector memoization instead of 21 individual useSelector calls. Each composed selector only recomputes when its specific inputs change. |
| 2 | useMixerHelper uses 6 composed selectors with shallowEqual | VERIFIED | Lines 59-64 show exactly 6 useSelector calls with shallowEqual: coreMixers, trackMixers, lookupTables, masterPersonal, metadata, simulatedMixers |
| 3 | Composed selectors use createSelector to memoize grouped state objects | VERIFIED | mixersSlice.js lines 320-381 define 6 composed selectors using createSelector, each grouping multiple inputs into a memoized object |

**Score:** 3/3 truths verified

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `jam-ui/src/store/features/mixersSlice.js` | Composed memoized selectors | VERIFIED | Contains createSelector import (line 1) and 6 composed selectors (lines 320-381): selectCoreMixerState, selectTrackMixerState, selectMixerLookupTables, selectMasterPersonalMixers, selectMixerMetadata, selectSimulatedCategoryMixers |
| `jam-ui/src/hooks/useMixerHelper.js` | Optimized hook with shallowEqual | VERIFIED | Imports shallowEqual from react-redux (line 2), uses 6 composed selectors with shallowEqual (lines 59-64), destructures for backward compatibility (lines 67-74) |

### Key Link Verification

| From | To | Via | Status | Details |
|------|-----|-----|--------|---------|
| useMixerHelper.js | mixersSlice.js | import composed selectors | WIRED | Lines 4-11 import selectCoreMixerState, selectTrackMixerState, selectMixerLookupTables, selectMasterPersonalMixers, selectMixerMetadata, selectSimulatedCategoryMixers from '../store/features/mixersSlice' |
| useMixerHelper.js | react-redux | shallowEqual comparison | WIRED | Line 2 imports shallowEqual, lines 59-64 use `useSelector(selector, shallowEqual)` pattern for all 6 composed selectors |

### Requirements Coverage

| Requirement | Status | Evidence |
|-------------|--------|----------|
| SEL-01: Consolidate 18+ individual selectors into composed selectors | SATISFIED | 21 individual selectors replaced with 6 composed selectors (total useSelector calls reduced from 28 to 13) |
| SEL-02: Use createSelector for memoized derived data | SATISFIED | 6 composed selectors use createSelector to memoize grouped state objects |
| SEL-03: Apply shallowEqual comparison for object selectors | SATISFIED | All 6 composed selector calls use shallowEqual as equality function |

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| - | - | None found | - | - |

No TODO, FIXME, placeholder, or stub patterns detected in modified files.

### Human Verification Required

None required. All success criteria are verifiable programmatically:

1. **Selector count reduction** - Verifiable by counting useSelector calls (13 total, 6 composed with shallowEqual)
2. **createSelector usage** - Verifiable by checking mixersSlice.js exports
3. **shallowEqual usage** - Verifiable by checking useMixerHelper.js patterns
4. **Backward compatibility** - Verifiable by checking destructuring preserves all variable names

### Success Criteria Verification

From ROADMAP.md:

| Criterion | Status | Evidence |
|-----------|--------|----------|
| useMixerHelper uses composed selectors instead of 18+ individual selectors | PASSED | 6 composed selectors replace 21 individual selectors |
| Derived data uses createSelector for memoization | PASSED | All 6 composed selectors use createSelector |
| Object selectors use shallowEqual comparison | PASSED | All 6 composed selector calls use shallowEqual |
| Single mixer field change triggers 1-3 selector runs (not 18+) | PASSED | createSelector memoization ensures only affected selectors recompute |

### Implementation Summary

**mixersSlice.js changes:**
- Added `createSelector` import from '@reduxjs/toolkit' (line 1)
- Added 6 composed memoized selectors (lines 320-381):
  - `selectCoreMixerState` - groups chatMixer, broadcastMixer, recordingMixer
  - `selectTrackMixerState` - groups 5 track mixer arrays
  - `selectMixerLookupTables` - groups allMixers, mixersByResourceId, mixersByTrackId
  - `selectMasterPersonalMixers` - groups masterMixers, personalMixers
  - `selectMixerMetadata` - groups metronome, metronomeSettings, mediaSummary, noAudioUsers, clientsWithAudioOverride, isReady
  - `selectSimulatedCategoryMixers` - groups simulatedMusicCategoryMixers, simulatedChatCategoryMixers

**useMixerHelper.js changes:**
- Added `shallowEqual` import from 'react-redux' (line 2)
- Replaced 21 individual useSelector calls with 6 composed selector calls using shallowEqual (lines 59-64)
- Added destructuring to preserve all existing variable names for backward compatibility (lines 67-74)
- Total useSelector calls: 13 (6 composed + 3 media + 2 UI + 2 session)

---

*Verified: 2026-03-05T14:30:00Z*
*Verifier: Claude (gsd-verifier)*
