Simple plugin to use mermaid.js in a jekyll-asciidoc + just-the-docs setup

Readme.md

Requires a working mermaid setup for just-the-docs.

Place the file below in the _plugins folder of your site. Now in your AsciiDoc files, you can do

[mermaid]
....
graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;
....

Stolen and minimally edited from GitLab, under MIT

Conflicts with AsciiDoctor Diagram, which renders during site generation.

asciidoc-mermaid-block.rb

begin
  require 'asciidoctor'

  class MermaidBlockProcessor < ::Asciidoctor::Extensions::BlockProcessor
    use_dsl

    named :mermaid
    on_context :literal, :listing
    parse_content_as :simple

    def process(parent, reader, attrs)
      create_mermaid_source_block(parent, reader.read, attrs)
    end

    private

    def create_mermaid_source_block(parent, content, attrs)
      # If "subs" attribute is specified, substitute accordingly.
      # Be careful not to specify "specialcharacters" or your diagram code won't be valid anymore!
      subs = attrs['subs']
      content = parent.apply_subs(content, parent.resolve_subs(subs)) if subs
      html = %(<div><pre class="language-mermaid">#{CGI.escape_html(content)}</pre></div>)
      ::Asciidoctor::Block.new(parent, :pass, {
        content_model: :raw,
        source: html,
        subs: :default
      }.merge(attrs))
    end
  end

  ::Asciidoctor::Extensions.register do
    block MermaidBlockProcessor
  end

rescue LoadError
end