html inline CSS properties into the style attribute

[SilvaQ]

Is it possible that we could combine the power of juice's library with our Rehype line and offer an ast extension?

Markdown to HTML special scenes need this ability, if we can customize it better!

Juice project address:
https://github.com/Automattic/juice

Given HTML, juice will inline your CSS properties into the style attribute.

[ChristianMurphy]

Could juice be used with Rehype? Yes
It works on raw HTML, so Rehype would need to stringify then re-parse to be integrated in the pipeline, or juice could be applied after Rehype is done.

offer an ast extension

It could be made a plugin with the stringify and re-parse approach noted above.
juice doesn't support ASTs and is unlikely to change anytime soon, given that it is not currently maintained Automattic/juice#399

That said, if you wanted to create an AST based alternative, you could.
In theory https://www.npmjs.com/package/hast-util-select could be used as an alternative to jQuery/Cheerio selectors to re-implement the functionality.