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Version: Next

Creating a New Architecture App

caution

This documentation is still experimental and details are subject to changes as we iterate. Feel free to share your feedback on the discussion inside the working group for this page.

Moreover, it contains several manual steps. Please note that this won't be representative of the final developer experience once the New Architecture is stable. We're working on tools, templates and libraries to help you get started fast on the New Architecture, without having to go through the whole setup.

This page will help you create a new React Native app that uses the New Architecture.

Development Environment​

Before continuing, make sure you've followed all the steps in the Setting up the development environment section under the React Native CLI Quickstart tab.

If following the setup guide, stop when you reach the section Running your React Native Application, and resume following this guide.

caution

If you're using Expo, you can't enable the New Architecture at the moment and will have to wait for a future release of the Expo SDK.

Creating a New Application​

If you previously installed a global react-native-cli package, please remove it as it may cause unexpected issues:

npm uninstall -g react-native-cli @react-native-community/cli

If you already have your development environment set up, create a new React Native project from the template:

npx react-native init AwesomeProject
caution

The New Architecture is available in React Native version 0.68 or later.

Configuration​

Follow the steps below to enable the New Architecture and build the app.

Enable Hermes​

Hermes is an open-source JavaScript engine optimized for React Native. Hermes will be the default engine in the future, and we highly recommend you use it.

Please follow the instructions on the React Native website to enable Hermes in your application.

Enable the New Architecture​

Target OS​

Set the newArchEnabled property to true by either:

  • Changing the corresponding line in android/gradle.properties
  • Setting the environment variable ORG_GRADLE_PROJECT_newArchEnabled=true

Then build and run the app as usual:

yarn android
note

You may notice longer build times with the New Architecture due to additional step of C++ compilation with the Android NDK. To improve your build time, see Speeding Up Your Build Phase.

Confirming the New Architecture is in Use​

After you build and run the app when Metro serves the JavaScript bundle, you should see "fabric": true in the Metro logs:

Metro shows fabric: true

Want to Know More?​

If you'd like to view the code changes relevant to the New Architecture, take a look at the upgrade helper from version 0.67.4 to 0.68.0. Files that were added for the New Architecture are marked with a yellow banner.

For further explanations of what each file is doing, check out these guides to walk through the changes step-by-step: Enabling The New Architecture in Your App