[gatsby-remark-prismjs] `diff` with language / highlight

Hi there!

Trying to understand a few things related to gatsby-remark-prismjs and how it may (or may not) differ from regular prismjs.

The prism site has an example of diff-highlighting and I’m trying to recreate that in my site (here’s my post).

Github’s preview is a good example of what I’m striving for:

On my site, however, I can’t seem to figure out how to get highlights - whether language specific or not:

I’ve tried

```diff-javascript
```diff javascript

And several other variants, but to no avail.

Interestingly, diff-javascript results in some weird encoding (note the undefined values that get appended to the ends of lines):

My questions:

1. Does gatsby-remark-prismjs support multi-language (diff + javascript for example)?
2. Does gatsby-remark-prismjs support line-highlighting (with the green/red, not the standard highlighting)?

Thanks!

[jon-sully]

Oh I see — this is coming from a separate, additional plugin.

https://github.com/DSchau/gatsby-remark-code-titles

I checked the code of that plugin just briefly and I don’t think there’s anything that should necessarily change how it works with gatsby-remark-prismjs. If it works for you now it should continue to without issue.

Feel free to pull down @jonsully/gatsby-remark-prismjs (latest version) and give it a try though

[jon-sully]

Greetings 👋🏻

This bothered me too, especially since I don’t use the line-highlighting implemented by this plugin. ~I modded a bit of the diff-sniffing code behind this plugin and published a variant (REVOKED) that injects the diff-highlight class. I likely won’t PR this repo with the changes because they’re not the cleanest and it sort of goes against Commonmark spec, but you’re welcome to use it if you’d like~:

~Give it a try if ya like. Your mileage may vary~

EDIT: Removed the above; this was a bad direction. I’ve since iterated and PR’d this repo with more reasonable and better changes. Instructions for installing until the PR is merged coming soon 👍🏻