React 19 support

[pierpo]

Is there an existing request?

• I have searched for this request

Describe the feature request

Hey,

I just tried setting up React 19 on my React Native Web project.

It doesn't work yet, as the following functions are not found anymore:

• unmountComponentAtNode in src/exports/unmountComponentAtNode/index.js
• domLegacyRender in src/exports/render/index.js
• domLegacyHydrate in src/exports/render/index.js
• findDOMNode in src/exports/findNodeHandle/index.js

They were deprecated with React 18 and won't work with React 19.

(Sorry, I haven't found any other topic mentioning the React 19 support)

Thanks 🙌

[necolas]

1. Use mode:concurrent => https://necolas.github.io/react-native-web/docs/app-registry/#appparams
2. Stop using findNodeHandle

I don't know what other changes are needed for React 19, but will review PRs as long as they don't break React 18 support. Any other issues are probably going to be traced back to React Native's APIs (e.g., findNodeHandle is being preserved in Fabric but has no analog in React DOM because of the removal of findDOMNode) and 3P libraries not being web compatible given the changes React is undergoing on web.

[javascripter]

There's an open PR that tries to support React 19.
I don't personally know whether these changes are enough but just posting the link here in case.
#2731

[FezVrasta]

React 19 is now stable, do you think someone could look at #2731? I tried to help with the review but I don't have a lot of context on how rnw works.