+Head.jsx is ignored for parametrized (@slug) routes in an SSG setup

[adrai]

Hi Vike team,

I’m experiencing an issue where the +Head.jsx file is ignored for parametrized routes (e.g. /pages/blog/@slug/+Head.jsx).
For static routes, the head tags are rendered as expected, but for dynamic routes like /blog/[slug], the <title> and meta tags from +Head.jsx do not appear in the HTML output (SSR/SSG).

What I’ve tried:

• Confirmed that +Head.jsx is present and correctly exports a React component using useData().
• My layout is exported as export { LayoutBlogPost as Layout } and uses the correct signature: ({ children, pageContext }).
• pageContext is always undefined in the layout for dynamic routes.
• I’ve added +onCreatePageContext.js to the route, but it did not resolve the issue.
• I’m using the latest versions of vike, vike-react, and react-head.

Expected:
The head tags defined in +Head.jsx should be rendered for dynamic routes, just like for static routes.

Actual:
Head tags of the parent +Head.jsx page are used for dynamic routes, and pageContext is undefined in the layout.

Repro steps:

1. Create a parametrized route (e.g. /pages/blog/@slug/+Page.jsx and /pages/blog/@slug/+Head.jsx)
2. Add meta tags and title in +Head.jsx
3. Build or prerender the site
4. Observe that the head tags of the parent +Head.jsx page are used for /blog/[slug] pages

Any ideas or workarounds? Is this a bug or am I missing a configuration step?

Thanks!

[brillout]

Are you using +onBeforePrerenderStart to pre-render your dynamic routes?

[brillout]

Have you seen that +Head is cumulative?

[brillout]

See also https://vike.dev/Head#cumulative

[adrai]

Have you seen that +Head is cumulative?

Yes, and that's ok since there is no title tag in the parent page +Head.jsx file...
There is just the normal title option in the config.js.

How do you address this?
I want a "Blog" title for the /blog page and an individual title "Blog first" for my /blog/first page (parametrized route)...

[adrai]

I may have found a solution: adrai/www-blog-mini@b9fb413

[brillout]

IIRC you had <title> defined twice (in two +Head.js files) in your repro.

And, yes, using the +title setting is the way to go for <title> (see docs).