This project was bootstrapped with Create React Native App.
Below you'll find information about performing common tasks. The most recent version of this guide is available here.
- Updating to New Releases
- Available Scripts
- Writing and Running Tests
- Customizing App Display Name and Icon
- Sharing and Deployment
- Tips and Tricks
You should only need to update the global installation of create-react-native-app very rarely, ideally never.
Updating the react-native-scripts dependency of your app should be as simple as bumping the version number in package.json and reinstalling your project's dependencies.
Upgrading to a new version of React Native requires updating the react-native, react, and expo package versions, and setting the correct sdkVersion in app.json. See the versioning guide for up-to-date information about package version compatibility.
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.
Runs your app in development mode.
Open it in the Expo app on your phone to view it. It will reload if you save edits to your files, and you will see build errors and logs in the terminal.
Runs the jest test runner on your tests.
Like npm start, but also attempts to open your app in the iOS Simulator if you're on a Mac and have it installed.
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).
This will start the process of "ejecting" from Create React Native App's build scripts. You'll be asked a couple of questions about how you'd like to build your project.
Warning: Running eject is a permanent action (aside from whatever version control system you use). An ejected app will require you to have an Xcode and/or Android Studio environment set up.
You can edit app.json to include configuration keys under the expo key.
To change your app's display name, set the expo.name key in app.json to an appropriate string.
To set an app icon, set the expo.icon key in app.json to be either a local path or a URL. It's recommended that you use a 512x512 png file with transparency.
This project is set up to use jest for tests. You can configure whatever testing strategy you like, but jest works out of the box. Create test files in directories called __tests__ to have the files loaded by jest. See the the template project for an example test. The jest documentation is also a wonderful resource, as is the React Native testing tutorial.
Create React Native App does a lot of work to make app setup and development simple and straightforward, but it's very difficult to do the same for deploying to Apple's App Store or Google's Play Store without relying on a hosted service.
Expo provides free hosting for the JS-only apps created by CRNA, allowing you to share your app through the Expo client app. This requires registration for an Expo account.
Install the exp command-line tool, and run the publish command:
$ npm i -g exp
$ exp publish
You can also use a service like Expo's standalone builds if you want to get an IPA/APK for distribution without having to build the native code yourself.
If you want to build and deploy your app yourself, you'll need to eject from CRNA and use Xcode and Android Studio.
This is usually as simple as running npm run eject in your project, which will walk you through the process. Make sure to install react-native-cli and follow the native code getting started guide for React Native.
If you have made use of Expo APIs while working on your project, then those API calls will stop working if you eject to a regular React Native project. If you want to continue using those APIs, you can eject to "React Native + ExpoKit" which will still allow you to build your own native code and continue using the Expo APIs. See the ejecting guide for more details about this option.
- If you have a local network the prevents your phone from accessing the address that is printed when running the packager, you can often work around this issue by "tethering" your computer to your phone's internet connection. Some phones call this feature "mobile hotspot." While it's very convenient, if you have a data plan where you pay for data transfer you should be careful when using this feature, especially when installing dependencies from NPM.