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Expo Application Services
API Reference

Add Expo to an existing project

Learn how to add Expo SDK to an existing React Native project.


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Are you migrating from react-native-unimodules? If yes, please refer to the Expo modules migration guide.

To use Expo modules in your app, you will need to install and configure the expo package.

The expo package has a small footprint; it includes only a minimal set of packages that are needed in nearly every app and the module and autolinking infrastructure that other Expo SDK packages are built with. Once the expo package is installed and configured in your project, you can use npx expo install to add any other Expo module from the SDK.

Depending on how you initialized the project, there are two ways you can install the Expo modules: automatic or manual.

Automatic installation

To install and use Expo modules, the easiest way to get up and running is with the install-expo-modules command.

Terminal
# Install and configure the expo package automaticallynpx install-expo-modules@latest
  • Status-success-icon When the command succeeds, you will be able to add any Expo module in your app! Proceed to Usage for more information.

  • Status-failed-icon If the command fails, please follow the manual installation instructions. Updating code programmatically can be tricky, and if your project deviates significantly from a default React Native project, then you need to perform manual installation and adapt the instructions here to your codebase.

Manual installation

The following instructions apply to installing the latest version of Expo modules in React Native 0.68.

Terminal
npm install expo

Once installation is complete, apply the changes from the following diffs to configure Expo modules in your project. This is expected to take about five minutes, and you may need to adapt it slightly depending on how customized your project is.

Configuration for iOS

Optionally, you can also add additional delegate methods to your AppDelegate.mm. Some libraries may require them, so unless you have a good reason to leave them out, it is recommended to add them. See delegate methods in AppDelegate.mm.

Save all of your changes. In Xcode, update the iOS Deployment Target under Target → Build Settings → Deployment to iOS 12.0. The last step is to install the project's CocoaPods again in order to pull in Expo modules that are detected by use_expo_modules! directive that we added to the Podfile:

Terminal
# Install podsnpx pod-install
# Alternatively, the run command will install them for youexpo run:ios

Configuration for Android

Usage

Verifying installation

You can verify that installation was successful by logging a value from expo-constants. Run expo install expo-constants, then run expo run:[android|ios] and modify your app JavaScript code to add the following:

import Constants from 'expo-constants';
console.log(Constants.systemFonts);

Using Expo SDK packages

Once the expo package is installed and configured in your project, you can use expo install to add any other Expo module from the SDK. Learn more in "Using Libraries".

Expo modules included in the expo package

The following Expo modules are brought in as dependencies of the expo package:

  • expo-application - Generates the installation id in remote logging in development. This module is optional and can be safely removed if you do not use expo-dev-client.
  • expo-asset - A JavaScript-only package that builds around expo-file-system and provides a common foundation for assets across all Expo modules.
  • expo-constants - Provides access to the manifest.
  • expo-file-system - Interact with the device file system. Used by expo-asset and many other Expo modules. Commonly used directly by developers in application code.
  • expo-font - Load fonts at runtime. This module is optional and can be safely removed, however; it is recommended if you use expo-dev-client for development and it is required by @expo/vector-icons.
  • expo-keep-awake - Prevents your device from going to sleep while developing your app. This module is optional and can be safely removed.

To exclude any of these modules, refer to the following guide on excluding modules from autolinking.

Excluding specific modules from autolinking

If you need to exclude Expo modules that you are not using but they got installed by other dependencies, you can use the expo.autolinking field in package.json:

{
  "name": "...",
  "dependencies": {},
  "expo": {
    "autolinking": {
      "exclude": ["expo-keep-awake"]
    }
  }
}

You can also exclude a specific platform by using exclude under the platform key:

{
  "name": "...",
  "dependencies": {},
  "expo": {
    "autolinking": {
      "exclude": ["expo-font"],
      "ios": {
        "exclude": ["expo-keep-awake"]
      }
    }
  }
}
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