React Native 0.64 - Hermes on iOS and React 17

React Native 0.64 RC0

React Native 0.64 RC0 was released this morning and it allows for enabling Hermes on iOS, React 17, and more! To test it out, run the following command:

npx react-native init RN064 --version 0.64.0-rc.0

Hermes on iOS

Hermes on iOS was teased a few weeks back and the full details are something we're waiting to hear more about from the developer - such as how this change will make it past Apple's walled-garden and what types of performance increases we can expect from this - but for now you can test it out yourself by simply modifying the following line in your Podfile:

  use_react_native!(:path => config[:reactNativePath], hermes_enabled: true)

Inline requires enabled by default

Inline Requires, while not new to React Native, will now be enabled by default. What does that mean exactly? We can now allow the Metro bundler to identify components that are able to be lazy loaded. For more details on this, check out the notes from the React Native 0.59 release.

React 17

Another big change in this release is the inclusion of React 17. This latest major release of React includes no new features - but the core change is underlying advancements making it easier to upgrade React itself. Think of it like a stepping stone release.

More

Plenty more changes are arriving in this update - a new profile-hermes CLI command for converting Hermes tracing profile to Chrome format, Hermes with Proxy support, Node 12 minimum requirements, etc. Be sure to check out the official release notes to learn more.