File structure

Expo · Reference cheat sheet

📋 Overview

Expo apps are mostly JS/TS under the project root (or src/), with config at the top level. Native ios/ / android/ appear after prebuild or in bare workflows; prefer Continuous Native Generation + plugins over hand-editing when possible.

🔧 Core concepts

• Entry — package.json "main" → expo-router/entry or node_modules/expo/AppEntry.js.
• Router — Expo Router uses app/ file-based routes.
• Assets — assets/ for icons, splash, fonts.
• Config — app.config.ts, eas.json, babel.config.js, metro.config.js.
• Native — generated ios/, android/ (gitignore in managed CNG setups).

💡 Examples

MyApp/
  app/                 # Expo Router screens
    _layout.tsx
    index.tsx
    settings.tsx
  assets/
    icon.png
    splash.png
  src/
    components/
    lib/
  app.config.ts
  eas.json
  package.json
  tsconfig.json
  # after prebuild:
  ios/
  android/

// package.json (Router)
{
  "main": "expo-router/entry",
  "scripts": {
    "start": "expo start",
    "android": "expo run:android",
    "ios": "expo run:ios"
  }
}

⚠️ Pitfalls

• Committing generated native projects while also relying on prebuild — pick a workflow.
• Putting screens outside app/ when using Expo Router without registering them.
• Huge assets/ without compression → install size.

🔗 Related

• config.md — app config
• commands.md — prebuild / start
• plugins.md — native customization
• build.md — CI builds