Module to expose build config variables set in Gradle to your javascript code in React Native.

iOS version greatly contributed by maddijoyce

npm i react-native-build-config

⚠️ For React Native < 0.60, use version 0.1.0 and use manual linking (see below)

Declare config variables in Gradle, under android/app/build.gradle:

android { defaultConfig { buildConfigField "String", "API_URL", '"https://myapi.com"' buildConfigField "Boolean", "SHOW_ERRORS", "true" ... 

Or declare them in your info.plist file in your ios project.

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0">	<dict> <key>API_URL</key>	<string>https://myapi.com</string> <key>SHOW_ERRORS</key> <true /> ... 

Then access those from javascript:

const BuildConfig = require('react-native-build-config') BuildConfig.API_URL // "https://myapi.com" BuildConfig.SHOW_ERRORS // true

Gradle sets some variables by default:

• VERSION_NAME and VERSION_CODE, both coming from the build settings. Keep in mind the code is a number
• APPLICATION_ID: Your package name, eg: com.Example
• DEBUG: set to true when running the app locally
• BUILD_TYPE and FLAVOR: more build settings

ProGuard/R8 by default removes BuildConfig class from release Android build. JavaScript BuildConfig object will be undefined.

To keep it add the following line to proguard-rules.pro file

-keep class **.BuildConfig { *; } 

You can replace ** with your.package.name.

Native modules are auto-linked since v0.60. If you have a lower version, you need this:

1. Include this module in android/settings.gradle:

include ':react-native-build-config' include ':app' project(':react-native-build-config').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-build-config/android') 

2. Add a dependency to your app build in android/app/build.gradle:

dependencies { ... compile project(':react-native-build-config') } 

3. Change your main activity to add a new package, in android/app/src/main/.../MainActivity.java:

import com.ismaeld.RNBuildConfig.RNBuildConfigPackage; // add import public class MainApplication extends Application implements ReactApplication { private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) { /* ... */ @Override protected List<ReactPackage> getPackages() { return Arrays.<ReactPackage>asList( new MainReactPackage(), new RNBuildConfigPackage(BuildConfig.class), // add the package here ); } };