Error: Cannot access url.searchParams on a page with prerendering enabled in +server.ts

[kesdigital]

Am building a blog with mdsvex with an endpoint that can be called for a specific number of articles, with that number being specified as a query string, this works well in development with prerender = true set and the root +layout.server.ts but fails when I build for production.

Error: Cannot access url.searchParams on a page with prerendering enabled

Removing the url.searchParams.get('limit') line or setting prerender = false gets rid of the error, but this doesn't feel right, +server.ts can't be pre-rendered, why am I getting the error, is it a bug?.

export const GET: RequestHandler = async ({url, params}) => {
  try {
    const limitParam = url.searchParams.get('limit');
    const limit = limitParam ? parseInt(limitParam) : 6;
    const articles = await fetchArticles(limit);
    return json(articles);
  } catch (err) {
    console.log(err)
    throw error(500, 'An error occurred while fetching the posts')
  }
};

This endpoint is in it's own routes/api/article directory with no +page.svelte files.

Package info

"@sveltejs/adapter-auto": "^1.0.0-next.75"
"@sveltejs/kit": "^1.0.0-next.483"

[teemingc]

From the docs:

Note that you can still prerender pages that load data based on the page's parameters, such as a src/routes/blog/[slug]/+page.svelte route.

Accessing url.searchParams during prerendering is forbidden. If you need to use it, ensure you are only doing so in the browser (for example in onMount).

https://kit.svelte.dev/docs/page-options#prerender-when-not-to-prerender

As a side note, you only receive the error during build because pre-rendering only occurs during build.