mobile

Imported from Zhan1bek/arqa (apps/mobile/AGENTS.md). Install upstream with npx skills add Zhan1bek/arqa --skill mobile. Copyright stays with the author.

This is an Expo/React Native mobile application. Prioritize mobile-first patterns, performance, and cross-platform compatibility.

Expo has changed — do not trust your training data

Expo ships breaking changes every SDK release. APIs you remember are likely renamed, moved, or removed. Before writing any code that touches an Expo, EAS, or React Native API:

1. Read the major version of the expo package in package.json.
2. Fetch the matching versioned docs: https://docs.expo.dev/versions/v<major>.0.0/
3. For anything else, fetch https://docs.expo.dev/llms.txt — an index of all Expo docs with corrections to common LLM misconceptions. Follow its links to the specific page you need; never answer from memory.

Commands

Use bunx instead of npx if the project uses bun (bun.lock present).

npx expo install <package>  # ALWAYS use instead of npm/yarn/pnpm/bun add — resolves SDK-compatible versions
npx expo start              # start the dev server
npx expo lint               # lint
npx tsc --noEmit            # typecheck
npx expo-doctor             # diagnose dependency and config issues
npx expo install --fix      # fix incompatible package versions

Run lint and typecheck before declaring any task done.

This app

• One screen (src/DayScreen.tsx), no router on purpose. If a second screen appears, add Expo Router then (routes in src/app/), not before.
• Business rules come from @diary/core (shared with the server). Never re-implement validation, money formatting or date logic here — see the root AGENTS.md.
• Logic that can be tested without React Native lives in src/lib/ and is covered by Vitest (npm test from the repo root). Keep components thin.
• API base URL: src/config.ts (EXPO_PUBLIC_API_URL, else the Metro host IP on a phone).
• A new trip id is created once per opened form and reused on every retry (ADR-0003).

Building with EAS

Use EAS to build, sign, and submit the app in the cloud (eas build, eas submit) and to ship over-the-air updates (eas update) — no local Xcode or Android Studio required. Run EAS CLI as bunx eas-cli <command> in Bun projects, or npx eas-cli@latest <command> otherwise; substitute that for bare eas in docs examples. Docs: https://docs.expo.dev/eas/index.md

Rules

• If ios/ and android/ directories do not exist, they are generated (Continuous Native Generation). Never create or edit them by hand — configure native behavior in app.json and config plugins.
• Expo Go only includes its bundled native modules. After adding a library with native code, the app needs a development build: npx expo run:ios|android locally, or eas build --profile development.
• Prefer recommended Expo modules over third-party libraries, and check your available skills before adding dependencies. Docs: https://docs.expo.dev/versions/latest/index.md