Environment Setup

First things first, let’s get your development environment set up! Here’s what you’ll need to get started with React Native development using Expo.

Installing Node.js

We need Node.js as it’s the engine that runs our app. Head over to the Node.js website and grab the latest LTS version.

Important: If you previously installed the global expo-cli package, you should uninstall it to avoid conflicts:

npm uninstall -g expo-cli

Expo CLI is now included in the project dependencies and doesn’t need global installation.

Installing Xcode (for iOS Development)

If you plan to develop for iOS, you’ll need to install Xcode:

  1. Download Xcode from the Mac App Store
  2. Once installed, open Xcode to complete the installation of additional components
  3. Install the iOS Simulator by going to Xcode > Preferences > Components
  4. Install the Command Line Tools by running: 
    xcode-select --install

Make sure to also accept the Xcode license agreement:

sudo xcodebuild -license accept

Creating Your First Project

With Node.js installed, you can create a new Expo project:

npx create-expo-app@latest --template

Select Navigation (TypeScript) when prompted.

The setup includes typescript, and expo-router for navigation with basic layout to start building.

We’ll add environment configurations later for development, staging (called preview in EAS), and production, making it easier to manage different build configurations.

Running Your App

Once the project has been created, navigate to your project directory and start the development server:

cd your-project-name
npx expo start

Running on Simulators

You can run your app on iOS or Android simulators during development:

iOS Simulator

Either use npx expo run:ios or press i in the terminal when running npx expo start (if app has been installed)

Android Emulator

  1. Install Android Studio
  2. Set up an Android Virtual Device (AVD) in Android Studio
  3. Either use npx expo run:android or press a in the terminal when running npx expo start

The ANDROID_HOME environment variable must point to your Android SDK installation. On macOS, the default path is:

export ANDROID_HOME=/Users/$USER/Library/Android/sdk

Add this to your shell profile (.zshrc or .bash_profile) to make it permanent.

The JAVA_HOME environment variable must point to your Java SDK installation. For EAS builds, Java 17 is required. On macOS, if using Zulu JDK, the path is typically:

export JAVA_HOME=/Library/Java/JavaVirtualMachines/zulu-17.jdk/Contents/Home

If you encounter build errors mentioning Java or Android SDK not found, verify these environment variables are correctly set. You can check their current values with:

echo $JAVA_HOME
echo $ANDROID_HOME

For running on physical devices or more thorough build processes for simulator as well, please refer to our EAS setup guide which provides a more robust development and testing environment.

Additional Resources

For more detailed information about development environment setup, check out the Expo Development Environment Setup guide.