React Native Environment Setup.
Setting up a React Native development environment involves installing Node.js, Watchman, and a Java Development Kit (JDK), followed by configuring either Android Studio for emulation or setting up a physical device. For Android, you create an Android Virtual Device (AVD) in Android Studio, start the Metro Bundler, and run the app using npx react-native run-android. For iOS on macOS, you install Xcode, select a device in the simulator, and run the app using npx react-native run-ios.