Install Expo modules

info

macOS support for Expo modules is currently experimental.

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.

The following instructions apply to installing the latest version of Expo modules. For previous versions, check the Expo docs for compatibility for which Expo SDK version depends on a React Native version.

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 macOS

To configure your macOS project to use Expo modules, you'll need to make changes to the Podfile and your AppDelegate.

Start by modifying your Podfile to use the use_expo_modules! directive. This will enable autolinking for Expo modules in your project.

+require File.join(File.dirname(`node --print "require.resolve('expo/package.json')"`), "scripts/autolinking")
require_relative '../node_modules/@react-native-community/cli-platform-ios/native_modules'

 target 'myapp' do
-  config = use_native_modules!
+  use_expo_modules!
+
+  config_command = [
+    'npx',
+    'expo-modules-autolinking',
+    'react-native-config',
+    '--json',
+    '--platform',
+    'ios'
+  ]
+  config = use_native_modules!(config_command)

   use_react_native!(
-     :path => '../node_modules/react-native-macos',
+     :path => "#{config[:reactNativePath]}-macos",

Optionally, you can also add additional delegate methods to your AppDelegate.swift. 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.swift.

The last step is to install the project's CocoaPods again to pull in Expo modules that are detected by use_expo_modules! directive that we added to the Podfile:

# Install pods
npx pod-install

Configure Expo CLI for bundling on macOS

We recommend using Expo CLI and related tooling configurations to bundle your app JavaScript code and assets. This adds support for using the "main" field in package.json. Not using Expo CLI for bundling may result in unexpected behavior. Learn more about Expo CLI.

Use babel-preset-expo in your babel.config.js

-  presets: ['module:@react-native/babel-preset'],
+  presets: ['babel-preset-expo'],

Extend expo/metro-config in your metro.config.js

-const {getDefaultConfig, mergeConfig} = require('@react-native/metro-config');
+const { getDefaultConfig } = require('expo/metro-config');
+const { mergeConfig } = require('@react-native/metro-config');

 /**
  * Metro configuration

Configure macOS project to bundle with Expo CLI

Replace the shell script under Build Phases > Bundle React Native code and images in Xcode with the following:

if [[ -f "$PODS_ROOT/../.xcode.env" ]]; then
  source "$PODS_ROOT/../.xcode.env"
fi
if [[ -f "$PODS_ROOT/../.xcode.env.local" ]]; then
  source "$PODS_ROOT/../.xcode.env.local"
fi

# The project root by default is one level up from the ios directory
export PROJECT_ROOT="$PROJECT_DIR"/..

if [[ "$CONFIGURATION" = *Debug* ]]; then
  export SKIP_BUNDLING=1
fi
if [[ -z "$ENTRY_FILE" ]]; then
  # Set the entry JS file using the bundler's entry resolution.
  export ENTRY_FILE="$("$NODE_BINARY" -e "require('expo/scripts/resolveAppEntry')" "$PROJECT_ROOT" ios relative | tail -n 1)"
fi

if [[ -z "$CLI_PATH" ]]; then
  # Use Expo CLI
  export CLI_PATH="$("$NODE_BINARY" --print "require.resolve('@expo/cli')")"
fi
if [[ -z "$BUNDLE_COMMAND" ]]; then
  # Default Expo CLI command for bundling
  export BUNDLE_COMMAND="export:embed"
fi

`"$NODE_BINARY" --print "require('path').dirname(require.resolve('react-native/package.json')) + '/scripts/react-native-xcode.sh'"`

And add support the "main" field in package.json by making the following change to AppDelegate.swift:

   override func bundleURL() -> URL? {
 #if DEBUG
-    RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: "index")
+    RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: ".expo/.virtual-metro-entry")
 #else
     Bundle.main.url(forResource: "main", withExtension: "jsbundle")
 #endif

Usage

Verifying installation

You can verify that the installation was successful by logging a value from expo-constants.

• Run npx expo install expo-constants
• Then, run npx expo run 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 npx expo install to add any other Expo module from the SDK. See Using Expo Libraries for more information.

Expo modules included in the expo package

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

• 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 native code from Expo modules you are not using, but were installed by other dependencies, you can use the expo.autolinking.exclude property in package.json:

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