Plugin Options & CDN Assets

marko-run is zero-config by conviction, but its Vite plugin takes options when you need them. Three worth knowing: routesDir moves the routes folder (the docs discourage it — the default is a shared convention); trailingSlashes picks how /about/ relates to /about (five modes; the default RedirectWithout gives each page one canonical URL, which search engines like); and adapters are auto-discovered from your dependencies — installing @marko/run-adapter-netlify is the configuration.

The star option is for production: basePathVar. In dev, Vite serves your assets. In production there is no Vite — the built server inlines asset URLs into its HTML, and if those assets live on a CDN (the usual practice: upload dist/ to a resource server at deploy time), every URL needs the CDN base prepended. This lesson’s project already declares it in vite.config.ts:

plugins: [marko({ basePathVar: "__MY_ASSET_BASE_PATH__" })]

That tells the built server: read the base from this global at startup. Setting it is your job — and the root +middleware.ts is the right home: its module top-level runs exactly once when the server boots.

Try the failure first — it’s a good one:

1. In the terminal, build to a folder of its own: pnpm run build --output dist-prod
2. Start the built server on its own port: pnpm run preview --output dist-prod --port 3100 It crashes immediately: __MY_ASSET_BASE_PATH__ must be defined when using basePathVar. Production refuses to guess.
3. In +middleware.ts, uncomment the assignment (pretend the URL came back from your CDN upload).
4. Rebuild and serve again: pnpm run build --output dist-prod then pnpm run preview --output dist-prod --port 3100
5. In a second terminal tab (or stop the server with Ctrl+C and restart it after looking), ask it for the page: curl -s localhost:3100 | grep -o 'src="[^"]*"' — every asset URL now starts with the CDN base. (Nothing is actually hosted at cdn.example.com; the URL is the lesson.)

You should see the crash message in step 2 and CDN-prefixed src URLs in step 5. Last lesson: where to go from here.