A mermaid-js one could be written based on the old graphviz one:

https://secure.phabricator.com/P1853

Maybe this could be integrated in the Diagrams extension...? I mean: the entire infrastructure is there - you just have to decide, what lib you wanne use when creating a new diagram. @mturdus What do you think about this?

If Phorge adds this feature, it is a good opportunity to be nice to thousands of people who use GitLab and GitHub, to unify with their syntax. Visible here:

https://github.blog/2022-02-14-include-diagrams-markdown-files-mermaid/

The Github syntax for this is bad. That's the code block syntax. It makes it impossible to have code-block with mermaid syntax.

We should copy good features, not bad ones.

Anyway, this should be an extension, not part of core.

Well, my idea was to use the already implemented logic of the diagram extension and just extend it with another diagram renderer. But @mturdus is not responding 😁

@avivey I think you are right. To render another thing than code in a code block seems bad design decision.

Sorry for the late reply.
The Diagrams extension (which just references the draw.io codebase) already has something like that in it.
You can use {DIAG1} in remarkup for showing Diagram 1 in e.g. a wiki document.
You can also import Mermaid diagrams in here.

Most of the draw.io javascript functionality is minified in the webapp/js/app.min.js file.
Referencing this Mermaid functionality in here will not be easy and will definitely not be manageable.

I have edited the answer. Because with draw.io you can integrate Mermaid out of the box. With R5 you can start using the syntax like instantly.