Table of Contents

• Prerequisites
  • For iOS
  • For Android
• Usage
  • Usage for iOS
  • Usage for Android
• Available Scripts
  • npm start
  • npm test
  • npm run ios
  • npm run android
• Troubleshooting
  • Networking
  • iOS Simulator won't open

Prerequisites

• node (tested with versions 7.x and 9.x of)
• npm (tested with versions 4.x and 5x)

For Android

• Android SDK
• ANDROID_HOME environment variable set to the root of the SDK director
• PATH environment variable should include $ANDROID_HOME/platform-tools It's recommended to have Genymotion installed for emulation

For iOS

• Xcode
• Cocoa Pods must be configured

Usage

1. npm i -g react-native-cli
2. npm install
3. npm test

Usage for Android

4. Start your emulator of choice or connect and enable development options in your selected device
5. react-native run-android

Usage for iOS

4. Enter the ios directory and run pod install
5. Open the project in Xcode (select the pod workspace file inside ios directory)
6. Select your emulator or connect a device and select it from the list (authorize the installation of the app in the device)
7. Run from Xcode

For collaborators

Make sure you run: npm test && npm run flow before submitting your code

Available Scripts

If Yarn was installed when the project was initialized, then dependencies will have been installed via Yarn, and you should probably use it to run these commands as well. Unlike dependency installation, command running syntax is identical for Yarn and NPM at the time of this writing.

npm start

Runs your app in development mode.

Sometimes you may need to reset or clear the React Native packager's cache. To do so, you can pass the --reset-cache flag to the start script:

npm start -- --reset-cache
# or
yarn start -- --reset-cache

npm test

First runs the linter (see https://eslint.org/) and then runs the jest test runner on your tests.

react-native run-ios

Like npm start, but also attempts to open your app in the iOS Simulator if you're on a Mac and have it installed.

react-native run-android

Like npm start, but also attempts to open your app on a connected Android device or emulator. Requires an installation of Android build tools (see React Native docs for detailed setup). We also recommend installing Genymotion as your Android emulator. Once you've finished setting up the native build environment, there are two options for making the right copy of adb available to Create React Native App:

Using Android Studio's adb

1. Make sure that you can run adb from your terminal.
2. Open Genymotion and navigate to Settings -> ADB. Select “Use custom Android SDK tools” and update with your Android SDK directory.

Troubleshooting

Networking

If you're unable to load your app on your phone due to a network timeout or a refused connection, a good first step is to verify that your phone and computer are on the same network and that they can reach each other. Create React Native App needs access to ports 19000 and 19001 so ensure that your network and firewall settings allow access from your device to your computer on both of these ports.

Try opening a web browser on your phone and opening the URL that the packager script prints, replacing exp:// with http://. So, for example, if underneath the QR code in your terminal you see:

exp://192.168.0.1:19000

Try opening Safari or Chrome on your phone and loading

http://192.168.0.1:19000

and

http://192.168.0.1:19001

If this works, but you're still unable to load your app by scanning the QR code, please open an issue on the Create React Native App repository with details about these steps and any other error messages you may have received.

If you're not able to load the http URL in your phone's web browser, try using the tethering/mobile hotspot feature on your phone (beware of data usage, though), connecting your computer to that WiFi network, and restarting the packager.

iOS Simulator won't open

If you're on a Mac, there are a few errors that users sometimes see when attempting to npm run ios:

• "non-zero exit code: 107"
• "You may need to install Xcode" but it is already installed
• and others

There are a few steps you may want to take to troubleshoot these kinds of errors:

1. Make sure Xcode is installed and open it to accept the license agreement if it prompts you. You can install it from the Mac App Store.
2. Open Xcode's Preferences, the Locations tab, and make sure that the Command Line Tools menu option is set to something. Sometimes when the CLI tools are first installed by Homebrew this option is left blank, which can prevent Apple utilities from finding the simulator. Make sure to re-run npm/yarn run ios after doing so.
3. If that doesn't work, open the Simulator, and under the app menu select Reset Contents and Settings.... After that has finished, quit the Simulator, and re-run npm/yarn run ios.

To do

• Evaluate normalizr, reselect