HabitTracker

A small habit-tracker built with Expo (React Native), running on iOS, Android, and web from one codebase. Track daily habits — either simple check-offs or counted targets — keep streaks alive, run time-boxed challenges, and get a little multi-sensory reward (haptic + chime + visual burst) every time you complete one.

Features

• Two habit kinds — check (once a day) or count (hit a per-day target, e.g. 8 glasses of water).
• Streaks & history — current consecutive-day streaks, a 7/30-day consistency chart, and a newest-first completion timeline.
• Challenges — time-boxed goals (e.g. a 7-day streak) that advance as you complete habits and celebrate on completion.
• Daily reminders — per-habit local notifications.
• Reward feedback — success haptic, a generated chime, and an on-screen burst on each completion.
• Light/dark theming and persistence across reloads (AsyncStorage), with a schema-migration path.

Requirements

This project is pinned to Expo SDK 54 on purpose — the owner tests on-device via the App Store build of Expo Go, which only supports SDK 54. Don't bump expo / expo-* / react-native / react without switching the device-testing story to a development build. See CLAUDE.md for the full rationale.

• Node.js (LTS)
• Expo Go on a device (SDK 54), or an iOS Simulator / Android Emulator

Getting started

npm install      # install dependencies
npx expo start   # start Metro; scan the QR with Expo Go, or press i / a / w

Or jump straight to a platform:

npm run ios       # iOS simulator
npm run android   # Android emulator
npm run web       # web build

Project layout

app/                 # Expo Router file-based routes
  (tabs)/
    index.tsx        # Today  — habit list, add-habit, challenge banner, reward
    explore.tsx      # Progress — consistency chart + completion grid
    history.tsx      # History — completed-day timeline
  onboarding.tsx     # first-launch welcome + starter challenge
  settings.tsx       # sound toggle, per-habit reminders
  modal.tsx          # celebration modal
hooks/
  use-habits.ts      # the core store: habits, challenges, settings + persistence
  use-reward.ts      # haptic + chime payoff
  use-notifications.ts
constants/theme.ts   # color palette
components/          # ThemedText/ThemedView + UI pieces

State lives in hooks/use-habits.ts: module-level stores exposed via useSyncExternalStore (no provider), persisted to AsyncStorage. See CLAUDE.md for the architecture in depth.

Scripts

Command	What it does
npm run lint	ESLint (eslint-config-expo)
npx tsc --noEmit	TypeScript type-check (strict)
npx expo-doctor	Validate dependencies against the SDK
node scripts/generate-chime.js	Regenerate the committed reward chime asset

There is no test framework configured — verify changes with tsc, expo-doctor, and by running the app.