Add custom toMarkdown parsers for embed

[aulneau]

Hi again :~)

I've been digging around and I had a couple questions around the embeds. I think it'd be really great to be able to pass custom toMarkdown methods with the embed. For example, I'm outputting my markdown to be consumed as mdx and I'd love to be able to control how the markdown for each embed is created.

Additionally, I was wondering if it'd be possible to change the default way of inputting data for the embed. Currently when an embed action/command fires, it will replace the menu with a string input field. I'd love to be able to pass any react component to that view. An example of why I'd like this: I want to give the users the ability to embed more than 1 image in the editor. I could create an embed that has: a custom toMarkdown method, a component, and a consumer component which would ultimately output the props that the component would need, and would be passed to the underlying attrs object.

Curious your thoughts @tommoor. Thanks again for this great library. I'd be happy to open some PRs if these ideas seem worthwhile (with some direction).

[tommoor]

I think it'd be really great to be able to pass custom toMarkdown methods with the embed. For example, I'm outputting my markdown to be consumed as mdx and I'd love to be able to control how the markdown for each embed is created.

Embeds can only be links – you'd also need a custom parser. I think at that point the best solution is probably to just create a new node type and pass that in through the extensions prop. You'd have to manually update the BlockMenu to include your custom node but other than that it should be plug-and-play.

I'd love to be able to pass any react component to that view

I like this idea, would accept a PR :)