detrogo/detrogo-react-native

Purpose and Runtime

DetroGo is an offline-first Delhi-NCR metro route-planning mobile app. It uses React Native, Expo, TypeScript, and Expo Router; native Android development-client builds are required for custom native functionality. Primary app configuration is app.json, with router entry layout at app/_layout.tsx.

Navigation and User Journeys

Expo Router screens define the app flow: onboarding, tabbed home/settings, station/route planning, route detail, and system-map views.

• Root and tab navigation: app/_layout.tsx, app/(tabs)/_layout.tsx

• Primary search/home UI: app/(tabs)/index.tsx, components/homescreenui.tsx

• Planning and presentation screens: app/planner.tsx, app/route.tsx, app/listpage.tsx

• First-run gating: app/onboarding.tsx

Transit Data Boundary

City-specific static datasets are the authoritative offline transit graph and display metadata. Delhi is currently the supported city; the city registry enables expansion without changing routing consumers.

• City registry: cities/index.ts

• Delhi topology and stations: cities/delhi/stationsdata.json, cities/delhi/lines.json, cities/delhi/metrolines.json

• Geometry and line metadata: cities/delhi/shapes.ts, cities/delhi/stationshapes.ts, cities/delhi/lineMeta.ts

Route Computation Pipeline

The planner takes selected origin/destination stations, resolves them against city data, and computes routes through the custom BFS/Dijkstra routing engine. Route domain contracts separate graph/routing results from screen rendering.

• Routing engine: utils/metroRouting.ts

• Route and routing types: types/route.ts, types/routing.ts, types/index.ts

• Geographic nearest-station lookup: utils/nearestStation.ts, store/useNearestStationStore.ts

The important boundary is static city data → routing utility → typed route result → planner/detail UI. GPS is used locally only to improve station selection; no backend is required for core routing.

Persistence and App State

Zustand-style stores own user-local state and persistence: onboarding completion, preferences, saved routes, and recent-trip history. This keeps route calculation/data independent of UI session state.

• Storage adapter: store/storage.ts

• Preferences and onboarding: store/usePrefStore.ts, store/onboarding.ts

• Route history/library: store/recentTrips.ts, store/savedRoutes.ts

Maps, Rendering, and Themes

The app exposes an in-app transit map and route schematic presentation. A bundled web renderer is present under assets/routemap, while MapLibre is the declared map-rendering technology. Material 3, dynamic colors, and AMOLED behavior are centralized outside feature screens.

• Bundled route-map renderer: assets/routemap/index.html, assets/routemap/assets/index-C3YrQ63w.js

• Theme/color system: constants/theme.ts, constants/m3Colors.ts, hooks/useAppTheme.ts

• AMOLED preference/rendering: constants/amoled.ts, hooks/useAmoled.ts

Notifications, Localization, and External Services

A local Expo native module package implements live-update notifications on Android, including Firebase token/service integration; route notification utilities connect app route state to that capability. Crowdin manages translation workflow; locale JSON is bundled with the app.

• Notification integration: utils/detroLiveNotif.ts, utils/routeNotification.ts

• Native live-update module: packages/expo-live-updates/android/src/main/java/expo/modules/liveupdates/ExpoLiveUpdatesModule.kt, packages/expo-live-updates/android/src/main/java/expo/modules/liveupdates/FirebaseService.kt

• Localization resources: i18n/locales/en.json, i18n/locales/hi.json, crowdin.yml