expo-native-launch-arguments

Note: This repository is a fork of react-native-launch-arguments by @iamolegga. I'm awaiting permission to push a branch and open a PR to the original repository. In the meantime, I created this separate repo to provide New Architecture and Expo managed workflow support. This repository can be deleted if the admin of the original repo requests it.

Expo module to get launch arguments.

Makes passing parameters from testing libraries and debug tools to React Native super easy.

Built with Expo Modules API using Swift and Kotlin.

Install

npm install expo-native-launch-arguments
npx expo prebuild

Or with yarn:

yarn add expo-native-launch-arguments
npx expo prebuild

Requirements

• Expo SDK 54+
• React Native 0.76+
• iOS 15.1+

Usage

JavaScript

import { LaunchArguments } from "expo-native-launch-arguments";

const args = LaunchArguments.value();
console.log(args); // { myKey: "myValue", myFlag: true }

TypeScript

import { LaunchArguments } from "expo-native-launch-arguments";

interface MyExpectedArgs {
  authToken?: string;
  skipAuth?: boolean;
}

const args = LaunchArguments.value<MyExpectedArgs>();

Integrating with End-to-end Testing Tools

The primary use case is with end-to-end testing tools like Detox.

Detox

await device.launchApp({
  launchArgs: {
    authToken: "test-token-123",
    skipOnboarding: true,
  },
});

• See device.launchApp({launchArgs:{...}})
• See launch arguments guide for full details.

Appium

capabilities: {
  optionalIntentArguments: `--ez myBool true --es myStr 'string text'`, // Android
  processArguments: { args: ['-myBool', 'true', '-myStr', 'string text'] }, // iOS
}

• optionalIntentArguments (Android) and processArguments (iOS)

Maestro

- launchApp:
    appId: "com.example.app"
    arguments:
      foo: "This is a string"
      isFooEnabled: false
      fooValue: 3.24

• arguments parameter of launchApp command

Xcode

In Xcode, add launch arguments in the Scheme editor:

• Product → Scheme → Edit Scheme... → Run → Arguments tab → Arguments Passed On Launch
• Prefix each argument with -

-hello "world"

This results in { "hello": "world" }.

Platform-specific Notes

iOS

Reads arguments from ProcessInfo.processInfo.arguments.

Verifying on iPhone Simulator

xcrun simctl launch booted com.MyAppBundleId -myKey "myValue"

Android

Reads from:

• intent.getBundleExtra("launchArgs") for Detox
• intent.getExtras() for ADB params

Passing args via ADB

adb shell am start -n com.example/.MainActivity --es myKey "myValue" --ez myBool true

Development

Building the library

npm run build

Running the example app

cd example
npm install
npx expo prebuild
npm run ios

Running Detox tests

cd example
npm run detox:ios

License

MIT