JSX compilation may not be compatible with React 19

[pzaczkiewicz-athenahealth]

Do you want to request a feature or report a bug?

Kind of a grey area. Not a bug yet, but it may be within 6 months. Depends on the final React 19 implementation.

What is the current behavior?

JSX is compiled into React.createElement

What is the expected behavior?

JSX is compiled into _jsx function where: import {jsx as _jsx} from 'react/jsx-runtime';

https://legacy.reactjs.org/blog/2020/09/22/introducing-the-new-jsx-transform.html

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

React 19, supposedly according to this documentation: https://react.dev/blog/2024/04/25/react-19-upgrade-guide#installing. However, the current release candidate doesn't appear to be creating these console errors yet. This JSX transform has been available since React 17, so there shouldn't be many apps still reliant on React 16.