i18n

vite.config.ts

@@ -1,3 +1,4 @@
+import { paraglideVitePlugin } from '@inlang/paraglide-js';
 import { sveltekit } from '@sveltejs/kit/vite';
 import tailwindcss from '@tailwindcss/vite';
 import { playwright } from '@vitest/browser-playwright';
@@ -29,8 +30,32 @@ const viteServerConfig = (): Plugin => ({
 	}
 });
 
+// Every locale carries its own path prefix, English included, so a URL always
+// says which language it is in. `trailingSlash: 'always'` (see routes/+layout.ts)
+// means the patterns have to match both `/de/weather/week/` and `/de`.
+const LOCALES = ['en', 'de', 'es', 'fr', 'it'] as const;
+
+const urlPatterns = [
+	{
+		pattern: '/:path(.*)?',
+		localized: LOCALES.map((locale) => [locale, `/${locale}/:path(.*)?`] as [string, string])
+	}
+];
+
 export default defineConfig({
-	plugins: [tailwindcss(), sveltekit(), viteServerConfig()],
+	plugins: [
+		paraglideVitePlugin({
+			project: './project.inlang',
+			outdir: './src/lib/paraglide',
+			// the URL is authoritative; the cookie only carries a choice forward to
+			// the next bare visit, and the browser's languages seed a first visit
+			strategy: ['url', 'cookie', 'preferredLanguage', 'baseLocale'],
+			urlPatterns
+		}),
+		tailwindcss(),
+		sveltekit(),
+		viteServerConfig()
+	],
 
 	test: {
 		expect: { requireAssertions: true },