Support React 19 Compatibility in Elastic UI

[pukarlamichhane]

Dear Elastic UI Team,

I would like to request support for React 19 in the Elastic UI library. As React continues to evolve, it is crucial for widely used libraries like Elastic UI to maintain compatibility with the latest versions to ensure smooth integration and avoid conflicts.

Reasons for the Request:
Community Adoption: Many projects are likely to upgrade to React 19 for its new features and performance improvements.
Library Interoperability: Ensuring compatibility prevents version mismatches and dependency issues.
Future-proofing: Supporting React 19 prepares the library for future updates and keeps it relevant in modern React ecosystems.
Request:
Update the peerDependencies in package.json to include support for React 19.
Test and validate Elastic UI functionality with React 19.
If there are breaking changes introduced in React 19, provide a roadmap or workaround.
Thank you for maintaining such an excellent library, and I hope this request can be considered in future updates.

[pukarlamichhane]

@kimjoar @gose @dmathieu @smith Sir, could you please help me with this task? I am a beginner-level developer, and your guidance would greatly help me improve my skills.

[smith]

@pukarlamichhane I'm not sure of any specific problems that would arise in trying to update EUI to support React 19. You probably can follow the React documentation on upgrading. EUI is primarily used in Kibana, so any changes to EUI must maintain backward compatibility with the version(s) of React used in Kibana (17, but 18 is in progress, it's complicated.)

If you are a beginning-level developer taking on this task, it would be good to set your expectations. This is something that could be ugly and difficult, and if you begin thinking you'll get your changes merged and finish the job you might be frustrated by the complexity of making a significant update to a large and important part of infrastructure like this.

If you decide to take this on, I would recommend doing it primarily as an exercise in learning and gaining understanding of the library and its ecosystem. The journey is the destination!