Upgrading to v1 seems to cause an issue when exporting arbitrary props

[brandonweiss]

Subject of the issue

Upgrading to v1 throws warnings on MDX documents that export arbitrary props, possibly because of the change from wrapping the document in a div to using a React Fragment?

Steps to reproduce

I have an MDX document like this:

export const author = "Foo"

# Heading

When I transform it I seem to get this warning:

Warning: Invalid prop `author` supplied to `React.Fragment`. React.Fragment can only have `key` and `children` props.
    in Fragment
    in MDXCreateElement
    in MDXContent

As far as I can tell, this is because all the props exported from the document are automatically passed to the “wrapper” component, which used to be a <div> and is now a <React.Fragment>.

The switch is fine and I think it makes sense, I’m just unclear if what is now happening is expected?

It seems like the default wrapper should be something like ({ children }) => <React.Fragment>{children}</React.Fragment>?

[LucidityDesign]

I get the same error using docz:

Warning: Invalid prop `entries` supplied to `React.Fragment`. React.Fragment can only have `key` and `children` props.

[johno]

I believe this has to do with using React.Fragment as the default wrapper element and forwarding all props. We'll need to change it from wrapper: React.Fragment to wrapper: ({ children }) => <React.Fragment>{children}</React.Fragment> in create-element.js.