How to include full MDX content in feed in gatsby-plugin-mdx v4

[danielpgross]

From https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-mdx/README.md#v3-to-v4-breaking-changes:

As mentioned above the html field was removed from the GraphQL node. We know that some of you used this for e.g. gatsby-plugin-feed. Unfortunately, for compatibility and performance reasons we had to remove it. We recommend using the excerpt field in the meantime until we find a feasible solution to provide MDX rendered as HTML. If you have any suggestions, please comment on the #25068.

How can we include full MDX content (not just an excerpt) in gatsby-plugin-feed items, now that the html field has been removed from MDX GraphQL nodes? Does a solution exist for this yet?

[timmb]

I've spent a day or so struggling with this, including trying to manually render the MDX on the needed pages in gatsby-node.js using compileMDXWithCustomOptions and manually creating a node field of the result. But the result is a string of javascript code and it's not clear how to make use of that without an MDXRenderer component.

I think I'll need to stick on Gatsby 4.20 until the the MDX plugin evolves.