React 18 support in React Native

[fluiddot]

Description

React 18 is not supported yet by React Native, however, the web version might use it soon. The purpose of this issue is mainly to collect information around this topic and open discussion about the better way to proceed.

Option 1 - Use React 18 in current RN version

The new React version comes with a React 17 mode in case the new concurrent rendered is not used (reference). This feature might allow us to use React 18 with the current React Native version.

In any case, the new APIs won't be available so we'd need to provide a mechanism to identify if these APIs are used in the code shared between platforms. This most likely could be achieved using unit tests and mocking the new APIs so they raise exceptions when they are used.

As a first step to validate this approach, we would need to upgrade React to version 18, and perform a test on the app to identify potential breakages.

Option 2 - Have two React versions

The idea would be to support both React versions 17 and 18 until React Native provides support for React 18. Therefore, each platform will use a different React version:

• Web version: React 18
• Native version: React 17

In order to accomplish this approach, we would need to explore how to have both versions in the Gutenberg repository.

[fluiddot]

This issue will be addressed when React Native version is upgraded to 0.68 (reference).

[geriux]

FYI we are currently working on the React Native upgrade that adds support for React 18. We will need to coordinate with the web team to align with these changes.

[fluiddot]

Closing this issue as React 18 support was incorporated in this PR.