Health Tracker

A React Native health monitoring app (Expo, TypeScript, Redux Toolkit, NativeWind) backed by a Next.js API over a local PostgreSQL database via Prisma. Track vitals, log symptoms, and receive real-time health alerts.

Monorepo layout

• mobile/ — Expo React Native app
• server/ — Next.js backend (REST API over local Postgres via Prisma; owns auth)
• docs/superpowers/ — design spec & implementation plan

Backend (server/)

cd server

# 1. Start Postgres and create the database
brew services start postgresql@14
createdb healthtracker

# 2. Environment
cp .env.example .env                 # DATABASE_URL (Prisma + Next read .env)
cp .env.local.example .env.local     # JWT_SECRET
# Default DATABASE_URL assumes Homebrew Postgres (user = your macOS login,
#   trust auth on localhost). Adjust if your setup differs.
# Set JWT_SECRET to a long random string, e.g. `openssl rand -hex 32`.

# 3. Install, migrate, seed
npm install
npx prisma migrate dev               # create tables
npx prisma db seed                   # test@healthtracker.dev / test1234

npm run dev          # http://localhost:3000
npm test             # alert logic / jwt / password unit tests
npx prisma studio    # browse the DB at http://localhost:5555

Prisma is pinned to v6. The Prisma CLI reads server/.env (not .env.local), so DATABASE_URL lives there; Next.js loads both.

API

Method	Path	Auth	Body
POST	/api/auth/signup	—	{ name, email, password }
POST	/api/auth/login	—	{ email, password }
GET	/api/auth/me	Bearer	—
GET	/api/entries	Bearer	—
POST	/api/entries	Bearer	vitals + symptoms + notes

Passwords are bcrypt-hashed; the server issues a 7-day JWT and is the source of truth for the hasAlert flag. The database is a local Postgres owned by Prisma migrations (server/prisma/) and reached only through this backend — the mobile app never connects to it directly. temperature is validated and stored in Celsius (34–42).

Mobile (mobile/)

cd mobile
cp .env.example .env
# Set EXPO_PUBLIC_API_URL to the backend URL.
# Physical device / emulator: use your machine's LAN IP, NOT localhost,
#   e.g. EXPO_PUBLIC_API_URL=http://192.168.1.50:3000
npm install
npx expo start       # press i / a / w, or scan the QR code
npx jest             # 35 unit tests (alert logic, validation, MetricCard)
npx tsc --noEmit     # typecheck

Run the backend first, then the mobile app pointed at it.

Architecture

mobile/src/
  navigation/  # RootNavigator: auth-gated; Auth(Login/Signup) ↔ Main tabs
  screens/     # Login, Signup, Dashboard, AddHealthEntry, History, Detail
  components/  # MetricCard, VitalInput, SymptomChip, AlertBanner, Button,
               # ScreenContainer (safe-area + responsive width), ErrorBanner,
               # EmptyState, EntryListItem
  store/       # Redux store + authSlice + healthSlice (API-backed thunks)
  services/    # api.ts (typed fetch client), storage.ts (JWT in SecureStore)
  utils/       # alertLogic (display), validation (zod), formatters
  types/       # shared interfaces & navigation param types
  constants/   # thresholds, symptom list, color palette

server/
  app/api/     # auth/{signup,login,me}, entries route handlers
  lib/         # prisma (client singleton), password (bcrypt), jwt,
               # auth guard, validation, alertLogic (source of truth),
               # thresholds, mappers
  prisma/      # schema.prisma, migrations/, seed.ts

Design decisions

• Next.js owns auth. Custom users table + bcrypt + app-issued JWT. The mobile app never talks to the database directly; all access goes through Prisma in the backend.
• Server computes alerts. checkForAlerts runs on the backend so the hasAlert flag can't be spoofed by the client (still used client-side purely for display banners).
• Responsive by default. ScreenContainer applies safe-area insets and a max content width so the UI works on notched phones, tablets, and web.
• Redux Toolkit retained for predictable, debuggable health-data state with built-in async-thunk loading/error handling.
• JWT-only SecureStore. Only the small token is persisted in the device secure enclave; entry history lives in Postgres (avoids SecureStore's ~2 KB per-value limit).

Known limitations

• No push notifications (expo-notifications not wired to alerts).
• No trend charts (react-native-chart-kit unused).
• No offline mode — the backend must be reachable.
• Local Postgres only; no per-environment config or hosted DB beyond .env.