22541 extract breadcrumb route-map helpers and add precedence guard tests

memory-bank/change-log.md

@@ -492,6 +492,46 @@ Follow-ups:
 - Next slice option A (larger): extract map constants + resolver helpers into a local `lib/routing/breadcrumbRouteMaps.js` pure module with focused tests, keeping callback/stateful branch rendering in component.
 - Next slice option B (smaller): expand structure tests to assert explicit map ordering invariants so future reordering regressions are caught early.
 
+### CL-22541-Q: breadcrumbs route-map helper module extraction + map-order invariants
+
+date: 2026-04-09  
+author: Cline  
+scope: `lib/routing/breadcrumbRouteMaps.js`, `components/breadcrumbs.js`, `tests/phase22/{breadcrumb-route-maps-helper,breadcrumbs-route-map-structure,index}.test.cjs`  
+type: change  
+rationale: Execute both queued follow-up slices together by extracting map composition/resolution logic into a pure routing helper module and adding stronger structure + pure-helper guardrails for map-order precedence.
+impact: Refactor-only structural modularization and test hardening; no intended route/auth/session/API/EN-CY/a11y behavior change.
+status: completed
+
+Summary:
+
+- Added new pure helper module `lib/routing/breadcrumbRouteMaps.js`:
+    - `buildBreadcrumbRendererMaps(...)`
+    - `getMappedRendererByPath(...)`
+    - `resolveMappedRouteRenderer(...)`
+- Updated `components/breadcrumbs.js` to import/use shared helper logic:
+    - map composition now via `buildBreadcrumbRendererMaps(...)`
+    - resolver now delegates to `resolveMappedRouteRendererByMaps(...)`
+    - dynamic/callback-sensitive explicit branches remain unchanged.
+- Added focused pure-helper tests in `tests/phase22/breadcrumb-route-maps-helper.test.cjs` for:
+    - map build order
+    - map lookup null/renderer behavior
+    - resolver precedence behavior
+- Expanded `tests/phase22/breadcrumbs-route-map-structure.test.cjs` to assert:
+    - component imports shared breadcrumb route-map helper module
+    - resolver delegation uses helper module
+    - map builder call preserves explicit ordering (simple -> link-text -> myportal)
+- Updated `tests/phase22/index.test.cjs` to include the new helper suite.
+
+Validation:
+
+- `npx eslint lib/routing/breadcrumbRouteMaps.js components/breadcrumbs.js tests/phase22/breadcrumb-route-maps-helper.test.cjs tests/phase22/breadcrumbs-route-map-structure.test.cjs tests/phase22/index.test.cjs` -> pass.
+- `node tests/phase22/index.test.cjs` -> pass (combined suite; breadcrumb-route-maps-helper 3/3; breadcrumbs-route-map 3/3).
+
+Follow-ups:
+
+- Next slice option A (larger): move per-path map object declarations out of `components/breadcrumbs.js` into module-level pure factories (still injected with `t/router/currentView`) to further shrink component body.
+- Next slice option B (smaller): add one focused parity test asserting mapped resolver fallback returns `null` in component rendering path for non-mapped routes (ensures no accidental render noise).
+
 ### CL-00X: 22500 `components/elements/index.js` Phase 1 helper extraction
 
 date: 2026-04-07