Bryan Hughes

Cobus let me know that the links in ToCs don't work in Safari

I think this function has some race condition when there are no headers at the level specified.  See https://observablehq.com/d/85ccba7714f6fe6f

Cobus Theunissen

Turns out it wasn't a race condition, the code to render was just never called. I just published a new version that throws an error when no headings are found

Anchors don't seem to work. Under these circumstances it might be better to not include anchors in the links.

Fabian Iwand

Tested in Firefox 90 and Chrome 91 (both macOS).

Nitpick: Looks like the condition for the if-block starting with "if (currentHeadings.length !== previousHeadings.length" can be inverted, allowing for another early return and a lowered indentation level for the remaining function body.

Thanks for the bug report, I need to spend a little time cleaning this up (it's slightly more broken on Safari too), and that's a good idea on the early return.

I can't think of a hack to make anchors work. In theory we could poll for the element and scroll it into view once it becomes available, but we'd have to abort the polling if the user scrolls. And we can't detect scroll events in the parent frame. :(

I removed the anchor hash, and it's working in FF and Chrome again (Safari never worked, and I can't work around it unfortunately). I think the only way to truly fix these fully is to get better support in the parent code to do something with this...I'll noodle on it.

I've started lazy loading this when used in library notebooks to avoid a static dependency
```js
toc = {
  const [{ Runtime }, { default: define }] = await Promise.all([
    import(
      "https://cdn.jsdelivr.net/npm/@observablehq/runtime@4/dist/runtime.js"
    ),
    import(`https://api.observablehq.com/@nebrius/indented-toc.js?v=3`)
  ]);
  const module = new Runtime().module(define);
  return module.value("toc");
}
```

Tom Larkworthy

toc() requires title to be a string, but does not actually escape it (e.g. "The <foo> element"). I'd recommend to pass strings through DOM.text(), and alternatively allow an Element instance to be passed in (in which case it shouldn't get wrapped in <b>).

Hah, looks like I don't remember my own code, we already use DOM.text().

Oh I see, you're talking about the value passed to the `title` property in the `toc()` options object, right?

Yep, and then the block starting with: if (typeof title === "string") {

Purpose-built for displays of data