React Native version 0.70 is officially released, this version has several improvements, such as a new unified configuration for Codegen, Hermes as the default engine, full CMake support for Android builds, and an update to the new architecture documentation.

The specific updates are as follows:

New Documentation for New Architecture

Over the past few months, Meta has been working hard to add more to the New Architecture section of the documentation. In the new section, you can find migration guides, examples and tutorials to get you up to speed as quickly as possible.

You’ll also find new documentation for an in-depth look at why there is a New Architecture and its parts. This can help you better understand the rationale behind the new API.

Hermes as default engine

React Native 0.70 was the first version to have Hermes enabled by default.

This is the result of a collaboration between the Hermes team and the React Native team, and Meta will work hard to improve and fine-tune Hermes to make it more performant and provide features that are highly requested by the community.

New unified configuration for Codegen

In version 0.70, a unified way to define Codegen specifications for iOS and Android was introduced. Previously you had to put Android configuration in a separate build.gradle file.

Now, you can define it directly in package.json:

  "codegenConfig": {
    "name": "CustomAnimationView",
    "type": "components",
    "jsSrcsDir": "./src",
    "android": {
      "javaPackageName": "com.custom.animation"
    }
  }

This improvement provides library maintainers with a more consistent experience when migrating their codebase to New Architecture.

Android Autolinking with New Architecture library

In version 0.70, users of New Architecture can automatically link the library without any additional configuration on their Android.mk or CMake files.

Autolinking is an important part of the React Native development experience.it allows you to use yarn add Commands include external libraries without dealing with CocoaPods or Gradle setup.

While autolinking works fine with the New Architecture library on iOS, it doesn’t on Android.This gap was closed in version 0.70, and you can now continue to include in your projects with yarn add libraries: they will be linked correctly on any architecture.

Full CMake support for Android builds

As of 0.70, users can now use CMake to configure their Native builds. Although you don’t want users of your application to write C++ code directly, you still need a natively compiled entry.

From now on you can use CMakeLists.txt file instead of Android.mk file to handle anything Android/Native related in your project.

Dependency upgrade

• Upgrade RN CLI to version 9.0.0
• Upgrade Android Gradle Plugin to 7.2.1
• Upgrade Gradle to 7.5.1
• Upgrade RCT-Folly to 2021-07-22
• Upgrade Metro to 0.72
• Upgrade SoLoader to 0.10.4

For more details, please check: https://reactnative.dev/blog/2022/09/05/version-070