| name | rn-fundamentals |
| description | Use at the start of any React Native or Expo task to lock in foundational choices: Expo managed workflow as default, latest Expo SDK with New Architecture ON, TypeScript, npm. Triggers on: "starting a new RN/Expo project", "what is the right architecture for an Expo app", "managed vs bare workflow", questions about Fabric/Hermes/JSI/New Architecture, "differences between RN and React web". Also triggers as a precondition when any other rn-* skill is selected and project setup is unclear. Not for: styling (rn-styling), navigation (rn-expo-router), data (rn-data-fetching). |
rn-fundamentals — foundational rules for React Native + Expo
This skill is the prerequisite read for any RN/Expo work. It sets the four non-negotiables and points you to deeper concept material when needed.
The 4 non-negotiables
- Expo managed workflow is the default. Bare workflow /
react-native init only if there is a documented native dependency Expo cannot wrap.
- Latest stable Expo SDK at bootstrap time, with New Architecture ON (
newArchEnabled: true in app.json). Hermes is the default JS engine — leave it on.
- TypeScript is mandatory. Template
blank-typescript. tsconfig.json extends expo/tsconfig.base.
- npm is the package manager (matches Expo defaults and
npx create-expo-app). No Yarn, no pnpm in this set.
Quick decision tree
- "Should I use Expo or bare RN?" →
references/decision-tree.md
- "What versions am I targeting?" →
references/stack-defaults.md
- "Why does X behave differently than React on the web?" →
references/concepts.md
- "Is this an OK pattern at the foundational level?" →
references/patterns.md
Common anti-patterns (NEVER do)
- ❌
npx react-native init when Expo managed would have worked — Expo is the default.
- ❌ Leaving New Architecture OFF on a new project — opt out only with a written reason.
- ❌ Mixing
yarn and npm install in the same project.
- ❌ Pinning Expo SDK to a version older than the current stable without justification.
Sources
