ukmesh/docs/frontend-map.md

Frontend Map

Current structure

• MapLibreMap.tsx
  • imperative MapLibre lifecycle, event wiring, and source refresh scheduling
• mapSourceLayers.ts
  • source/layer creation and exact layer identifiers
• geojsonBuilders.ts
  • pure GeoJSON builders and clash calculations
• mapConfig.ts
  • map constants and style config
• NodePopupContent.tsx
  • popup UI
• LiveOverlayController.tsx
  • live path overlay controller
• DeckGLOverlay.tsx
  • bounded packet-arc animation outside React map rerenders
• NodePopupContent.tsx and PlannedRepeaterPopup.tsx
  • selected-node and planned-repeater presentation

State ownership

• live nodes/packets: useNodes.ts
• coverage: useCoverage.ts
• links: useLinkState.ts
• overlay/path state: overlayStore.ts

Contributor rules

• do not reintroduce React-driven full-map rerenders for live packet/node traffic
• put pure map data shaping in builder modules, not in the top-level map component
• keep map visibility rules explicit and centralized where possible

Documented lifecycle exception

MapLibreMap.tsx is intentionally the single owner of one MapLibre instance. Splitting its lifecycle across React components would duplicate listeners, sources, or map construction during mount and Strict Mode. The component may coordinate lifecycle and call extracted helpers, but it must not absorb new pure computation, fetch policy, presentation markup, or persistent state.

The allowed responsibilities are:

• construct and destroy the map exactly once per mount
• register and unregister map events
• reconcile extracted source/layer definitions
• bridge the external live stores into bounded frame snapshots
• coordinate popups and imperative camera transitions

New code belongs in mapSourceLayers.ts, geojsonBuilders.ts, overlay controllers, hooks, or focused UI components as appropriate. A change that adds more than one coherent lifecycle responsibility must extract an existing responsibility in the same slice. Regression tests and the bundle/CSS budgets guard the boundary; map initialization must remain one instance per mount.