Fix TypeScript bug by adding workaround

[Methuselah96]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)
• If applicable, I’ve added docs and tests

Description of changes

Follow-up to #675. Adds | undefined as suggested in microsoft/TypeScript#48242 (comment).

Fixes this build error:

ERROR in ../../.yarn/__virtual__/react-markdown-virtual-1089d10e66/0/cache/react-markdown-npm-8.0.0-3d725f3756-61412ecd18.zip/node_modules/react-markdown/lib/react-markdown.d.ts 47:32-56
TS2307: Cannot find module 'mdast-util-to-hast/lib' or its corresponding type declarations.
    45 |   remarkPlugins?: import('unified').PluggableList | undefined
    46 |   rehypePlugins?: import('unified').PluggableList | undefined
  > 47 |   remarkRehypeOptions?: import('mdast-util-to-hast/lib').Options | undefined
       |                                ^^^^^^^^^^^^^^^^^^^^^^^^
    48 | }
    49 | export type LayoutOptions = {
    50 |   className?: string | undefined

[wooorm]

This goes against the idea of using TS through JSDoc, to solve an issue where TypeScript does not support PnP.
I’d rather use JSDoc as intended, where possible, and have TypeScript solve its issues, instead of applying unexplainable patches?

Related-to: syntax-tree/mdast-util-gfm#1 (comment).

[wooorm]

Any thoughts on my comment? I’m leaning on seeing this as an issue TS should solve.

[Methuselah96]

Would you be open to adding | undefined instead as suggested in microsoft/TypeScript#48242 (comment)?

[wooorm]

Where would that have to be added? Because the error line includes that undefined already.

Also it sounds kinda weird that adding undefined somewhere "fixes" an issue, and that both behaviors are expected.

[Methuselah96]

It would be added here:

-  * @property {import('remark-rehype').Options} [remarkRehypeOptions={}]
+  * @property {import('remark-rehype').Options | undefined} [remarkRehypeOptions={}]

[wooorm]

Oh I’m up for an explicit undefined, sure 👍, but I’d say report back that it’s really weird that you have to this one weird trick to get completely unrelated behavior 🤷‍♂️

[Methuselah96]

PR updated. I agree, feel free to add a comment to microsoft/TypeScript#48242. I haven't gotten a response to my last two comments.

[wooorm]

Thanks, released! https://github.com/remarkjs/react-markdown/releases/tag/8.0.2