Add BASE_PATH configuration for GitHub Pages subpath

Author: jacksteussie

.github/workflows/deploy.yml

@@ -25,6 +25,8 @@ jobs:
         run: pnpm install
 
       - name: Build
+        env:
+          BASE_PATH: '/${{ github.event.repository.name }}'
         run: pnpm run build
 
       - name: List build output

svelte.config.js

@@ -1,5 +1,7 @@
 import adapter from '@sveltejs/adapter-static';
 
+const dev = process.argv.includes('dev');
+
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
 	kit: {
@@ -9,7 +11,11 @@ const config = {
 			fallback: undefined,
 			precompress: false,
 			strict: true
-		})
+		}),
+		appDir: 'app',
+		paths: {
+			base: dev ? '' : process.env.BASE_PATH
+		}
 	}
 };