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.
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.
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
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). 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:
- Make sure that you can run adb from your terminal.
- Open Genymotion and navigate to
Settings -> ADB. Select “Use custom Android SDK tools” and update with your Android SDK directory.
- Find Genymotion’s copy of adb. On macOS for example, this is normally
/Applications/Genymotion.app/Contents/MacOS/tools/. - Add the Genymotion tools directory to your path (instructions for Mac, Linux, and Windows).
- Make sure that you can run adb from your terminal.
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.