> For the complete documentation index, see [llms.txt](https://faction-os.gitbook.io/faction-os-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faction-os.gitbook.io/faction-os-docs/.spec_system/archive/sessions/phase22-session05-store-folding-and-selectors/implementation_summary.md). # Implementation Summary **Session ID**: `phase22-session05-store-folding-and-selectors` **Package**: apps/web **Completed**: 2026-07-05 **Duration**: 0.8 hours *** ## Overview Implemented Phase 22 store folding for the web game projection aggregate. The web store now hydrates `gameProjection` from browser-local projection storage, folds every applied server event once through the pure reducer before existing store branch mutations, exposes narrow projection selectors, and resets in-memory projection state with `resetToSeed()` while leaving storage writes and erasure for later sessions. *** ## Deliverables ### Files Created | File | Purpose | Lines | | -------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | ----- | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/spec.md` | Session scope, requirements, and implementation plan. | \~205 | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/tasks.md` | Completed 18-task checklist. | \~64 | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/implementation-notes.md` | Task-by-task implementation evidence. | \~506 | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/code-review.md` | Code review and repair report. | \~102 | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/security-compliance.md` | Security and GDPR review report. | \~78 | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/validation.md` | Validation report with PASS result. | \~190 | | `.spec_system/specs/phase22-session05-store-folding-and-selectors/IMPLEMENTATION_SUMMARY.md` | Closeout summary. | \~81 | | `apps/web/tests/gameProjectionStore.test.ts` | Focused store integration tests for projection hydration, folding, selectors, replay/mock context, and reset memory behavior. | \~333 | | `docs/game-design/14-implemented-phases.md` | Game-design implemented-phase tracking. | \~28 | | `docs/game-design/15-phases-yet-to-be-implemented.md` | Game-design remaining-phase backlog tracking. | \~446 | ### Files Modified | File | Changes | | ------------------------------------------- | -------------------------------------------------------------------------------------------------------------------- | | `apps/web/src/store/useGameStore.ts` | Added projection imports, store field, hydration, one-event folding, selector helpers, and reset memory integration. | | `docs/game-design/README_game-design.md` | Linked implemented-phase and remaining-phase tracking documents. | | `.spec_system/state.json` | Marked Session 05 complete, cleared current session, and appended completion history. | | `.spec_system/PRD/phase_22/PRD_phase_22.md` | Updated progress tracker to 5/8 sessions complete and set next upcoming session to Session 06. | | `apps/web/package.json` | Bumped package version from 0.1.61 to 0.1.62. | | `package-lock.json` | Bumped the `apps/web` workspace lockfile version from 0.1.61 to 0.1.62. | *** ## Technical Decisions 1. **Store owns lifecycle, reducer owns logic**: Kept `gameProjection.ts` as the only projection authority and limited `useGameStore.ts` to hydration, context derivation, folding, selectors, and reset memory. 2. **Fold before switch mutations**: Invoked projection folding after replay capture and before the existing event switch so reducer behavior is independent of later branch mutations. 3. **Reference-change guard**: Updated `gameProjection` only when `reduceGameProjection` returned a new projection reference, preserving no-op stability for unknown or replay-guarded events. 4. **Hydration without persistence writes**: Loaded existing browser-local projection state at initialization but deferred writes, flush behavior, and erasure semantics to Sessions 06 and 08. *** ## Test Results | Metric | Value | | ------------------- | -------------------------------- | | Focused tests | 33 passed, 0 failed | | Full tests | 3192 passed, 1 skipped, 0 failed | | Package typecheck | PASS | | Workspace typecheck | PASS | | Biome check | PASS | | Coverage | Not collected | *** ## Lessons Learned 1. Store integration should keep projection changes visible through selectors while avoiding a second game-state authority. 2. Replay and mock context must be derived at the store boundary because the event stream itself cannot be trusted to distinguish synthetic or replayed traffic. 3. Storage recovery needs to be tested at module initialization because hydration failures are otherwise easy to miss. *** ## Future Considerations Items for future sessions: 1. Session 06 should add debounced persistence, max-latency/page-lifecycle flushing, and explicit storage removal behavior. 2. Session 07 should add broad honesty regressions for replay, reconnect, mock, and snapshot traffic across store folding. 3. Session 08 should document local erasure limits and validation evidence without implying broad trusted erasure. *** ## Session Statistics * **Tasks**: 18 completed * **Files Created**: 10 * **Files Modified**: 6 * **Tests Added**: 9 focused store integration tests * **Blockers**: 0 resolved --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://faction-os.gitbook.io/faction-os-docs/.spec_system/archive/sessions/phase22-session05-store-folding-and-selectors/implementation_summary.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.