TableOfContents with passthrough extension: empty list item

[deining]

Minimal working example

A markdown page with one single section:

## \(\TeX\)

PAGE.TableOfContents from this page looks like:

<nav id=\"TableOfContents\">
  <ul>
    <li>
      <a href=\"#tex\">(\\TeX)</a>
    </li>
  </ul>
</nav>

The single list item has the content (\\TeX), this is correct according to the commonmark spec for backslash escapes.

Now I enable the goldmark passthrough extension in my config file:

markup:
  goldmark:
    extensions:
      passthrough:
        enable: true
        delimiters:
          inline: [['\(', '\)']]

Now the PAGE.TableOfContents from this page now looks like this:

<nav id=\"TableOfContents\">
  <ul>
    <li>
      <a href=\"#tex\"></a>
    </li>
  </ul>
</nav>

Actual:

There is no inner content for the single list item.

Expected:

The inner content of the single list item should be \(\\TeX\).

Any help how to make this work is appreciated.

[irkode]

No Solution but maybe helps for someone to analyze

with passthrough

{{ debug.Dump .Fragments.Headings }}

{
  "tex": {
    "ID": "tex",
    "Level": 2,
    "Title": "",
    "Headings": null
  }
}

RenderHook: render-heading.html

<h{{ .Level }} id="{{ .Anchor }}" {{- with .Attributes.class }} class="{{ . }}" {{- end }}>
   {{ warnf "HEAD: %s" .Text }}
   {{ warnf "PLAIN: %s" .PlainText }}
  TEXT: {{ .Text -}}
  <hr/>
  PLAINTEXT: {{ .PlainText -}}
  {{- .Text -}}
</h{{ .Level }}>

WARN  HEAD: \(\TeX\)
WARN  PLAIN:                               <-- empty

without passthrough

{
  "tex": {
    "ID": "tex",
    "Level": 2,
    "Title": "(\\TeX)",
    "Headings": null
  }
}

WARN  HEAD: (\TeX)
WARN  PLAIN: \(\TeX\)

[jmooring]

See https://github.com/gohugoio/hugo/issues/12491.

Until this is addressed, continue to double-escape your expressions when placing them in a heading when using .Page.TableOfContents .

git clone --single-branch -b hugo-forum-topic-53532 https://github.com/jmooring/hugo-testing hugo-forum-topic-53532
cd hugo-forum-topic-53532
hugo server

[deining]

@jmooring

Until this is addressed, continue to double-escape your expressions when placing them in a heading when using .Page.TableOfContents .

Thanks for the advice. Double-escaping solved the issue, indeed.

[deining]

@jmooring

Until this is addressed, continue to double-escape your expressions when placing them in a heading when using .Page.TableOfContents .

I just realized that this advice cures the problem only when doing client side rendering of formulae with KaTeX. When doing server side rendering with transform.ToMath, a double-escaped expression is not rendered, but is printed as-is. Any way to work around this know issue when using transform.ToMath?

[jmooring]

I don’t know of any way around this. I’ve updated the issue accordingly:
https://github.com/gohugoio/hugo/issues/12491#issuecomment-2661535599

I also tried using tocbot.js instead. It failed, but differently.

[jmooring]

I was curious how GitHub handles this…

markup:

# Test TOC

## S1: $\sqrt{3x-1}+(1+x)^2$

## S2: [link](/a/b/)

## S3: some **bold** text

rendered (including their TOC):