Build hooks in dev mode

[SimonBerens]

Describe the bug

Build hooks seem to only run on build. I'm not sure if this is intentional, but it's not documented anywhere and I assumed that they would also run in dev mode.

Specifically, I want to dynamically add stylesheets based on frontmatter parameters, so I am using transformHead, but the link tags are not being added.

Reproduction

This reproduction uses meta tags instead of link tags.

https://stackblitz.com/edit/vite-9gbr2k?file=docs%2F.vitepress%2Fconfig.ts

Expected behavior

robots meta tag appears in dev mode

System Info

stackblitz

Additional context

No response

Validations

• Check if you're on the latest VitePress version.
• Follow our Code of Conduct
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[brc-dd]

You can use vite's transformIndexHtml to add extra head entries for now 👀 vitepress' transformPageData might also work. But I haven't tested yet.

[SimonBerens]

You can use vite's transformIndexHtml to add extra head entries for now 👀 vitepress' transformPageData might also work. But I haven't tested yet.

Thanks for the workaround suggestion!

An example where I encountered the more general "run a build hook in dev mode" is when I was trying to add an rss feed to my blog, similar to how the vuejs blog does it. It seems that I have to build my site for the rss feed to show up, but ideally buildEnd is run in dev mode as well so I can prototype my rss feed easily.

[brc-dd]

It won't be efficient to generate the feed on every content update 👀 It might be helpful while you're building the rss feed functionality, but after that, if buildEnd is run in dev, you'll have to wait for like seconds each time you update even a word in your markdown file.

[SimonBerens]

Why is that? I would think it's similar to other contentLoader calls. Is writeFile that slow?

[SimonBerens]

@brc-dd I don't think this should be tagged with has-workaround because there are a large set of problems (e.g. rss feed) that cannot be solved without having build hooks run in dev mode.