Markdown: Inline HTML & IDs from Extra Markdown not working

[aybassiouny]

Steps to reproduce the issue

1. Start a new jetpack site
2. Activate Markdown
3. Start a new post and add the following in a markdown block:

## Test inline html

<p> There should be no html tags </p>

## test anchors       {#header2}

There should be an an id for the above line, not extra markdown syntax.

4. Result

What I expected

According to Jetpack's Markdown documentation, the flavor of MD used is Markdown Extra. However, both IDs and inline html should be supported, which steps above show is not the case.

What happened instead

Special syntax is ignored and rendered on the screen instead. As a result, I am completely blocked from adding in-page links on my blog.

Screenshots

[jeherve]

Thanks for the feedback!

That's indeed a bit confusing. Jetpack's Markdown feature follows the Markdown Extra spec. The Markdown block, however, follows a different implementation that follows the CommonMark spec. CommonMark does not support manually set IDs as far as I can tell. You can check this thread to find out more:
https://talk.commonmark.org/t/anchors-in-markdown/247/32
This is also discussed here:
markdown-it/markdown-it#28

Adding raw HTML, however, is definitely something we could support in our block. I created an issue to track this in the wp-calypso repository, where we develop the block:
https://github.com/Automattic/wp-calypso/issues/30188

[bikedorkjon]

This came up in 2019865-zen