[Regression] Version 3.1.0 no longer traverses fragments in React 18

[benface]

In React 18, the following code used to render 2 section elements, now it renders a single one:

import flattenChildren from 'react-keyed-flatten-children'

const Component = ({ children, ...props }: ComponentPropsWithoutRef<'div'>) => {
  const childrenArray = flattenChildren(children)
  return <>childrenArray.map((child) => <section>{child}</section>)</>
}

return (
  <Component>
    <>
      <div>First item</div>
      <div>Second item</div>
    </>
  </Component>
)

CodeSandbox

[benface]

@grrowl – I confirm this bug only occurs in React 18. No issues in React 19. I added a repro link to my first post ☝️

[grrowl]

Thank you! I've reverted the React 19 changes as v3.2.0, and re-published React 19 under v4.0.0, and added a note to the README :)

https://github.com/grrowl/react-keyed-flatten-children/blob/master/README.md?plain=1#L5