TOC not displaying in Blogdown post (Hugo theme Even) - r

Question

I have added a new post to my site made using blogdown. Despite the presence of toc: yes in my YAML, the table of contents is not displaying on the rendered webpage. I've also tried adding:
output:
blogdown::html_page:
toc: yes
which doesn't solve the problem either. I'm currently using the Even theme (Hugo), and in the .config file, I also have toc: yes present.
I checked out this post, but I wasn't able to find the files they are referencing, nor those particular lines of code. Also my issue is with new posts, not the home page.
Does anyone know what the problem might be?
EDIT: I can see in my index.html file (generated from index.Rmd) that the code for a toc is present. For some reason, it's not being rendered on the page?

Answer 1

TL;DR Solution: to get the table of contents to show in the Even theme, your posts must render to the .markdown format instead of .html format. In order to make this happen, you simple use the .Rmarkdown file extension when creating the post instead of .Rmd. Now, when you use blogdown::serve_site(), your post will use the output format .markdown instead of .html. Your post will now render with a beautiful table of contents.
A note for latex math mode users: when typing in your .Rmarkdown document, you will now have to escape your $'s and \'s. So for example, $\le 0.2$
will have to be typed as \$\\le 0.2\$.
I hope this overly elaborate problem and solution is helpful to someone!
I figured out a workaround for this.
First, I'm not sure how to provide a reproducible example in this context, but I can say that if you open an RStudio project, run blogdown::new_site(theme = "olOwOlo/hugo-theme-even"), add a New Post using the Addin dropdown menu, add some headings to your post, make toc:true, use Serve Site from the Addin menu. You will see your post working fine in every respect - only it will be missing the table of contents.
Workaround:
I don't know why, but it appears that the table of contents will show if I keep a copy of the post in .md format, and delete the .html document. The default behavior seems to use the .html document if it is present; failing that, it will use the .md document.
To keep a copy of the post in .md format, use the following code in the YAML of your .Rmd document:
output:
blogdown::html_page:
keep_md: yes
Serve the site, delete the .html document (but keep the .md document), and the table of contents appears in all of its glory (you may have to actually knit the file to get the .md).
I don't know why this works...I've seen elsewhere (although I can't seem to find the post again) that some hugo themes don't play nicely with .html files, and prefer .md files, and that appears to be the case for the Even theme.
In sum: My workaround for now is thus to work on my posts, and when I'm done, knit the document with the option above, delete the .html file, and be on my way.
Caveat: blogdown seems to automatically re-render all the old posts when using Serve Site. According to this stack answer, Serve Site should only render documents that have undergone changes. Regardless, the old posts are most definitely being re-rendered, even when working on an unrelated post. I'm not sure if this behavior is attributable to blogdown per se, or the RStudio project.
I tried going to Tools -> Project Options -> Build Tools, and unchecking the boxes "Preview site when building", yet the behavior persists. Which means I will have to continuously delete these new .html files for all old posts every time a I make a change to any other file. Currently I only have one post, so not a big deal...yet.
If someone knows of a solution to this caveat, I would be extremely grateful. If I find one, I will edit this question and add it.
EDIT: it appears that blogdown will re-render the old post if there is no .html document present. Otherwise, it does not re-render it.
EDIT 2: Aha! According to the answer to this question, simply changing the file extension of the blog post from .Rmd to .Rmarkdown will produce a .markdown document instead of a .html document.