sparse desktop build

website/vite.config.ts

@@ -1,9 +1,50 @@
 import { sveltekit } from '@sveltejs/kit/vite';
 import { enhancedImages } from '@sveltejs/enhanced-img';
-import { defineConfig } from 'vite';
+import { defineConfig, type Plugin } from 'vite';
 import tailwindcss from '@tailwindcss/vite';
 import wasm from 'vite-plugin-wasm';
 
+/** Whether the website is built for the desktop app (`npm run build:desktop`), which only has the app. */
+const desktop = process.env.BUILD_TARGET === 'desktop';
+
+/** The pages of the website, which the desktop app opens on gpx.studio: home, help and embed. */
+const websitePage = /\/src\/routes\/\[\[language\]\]\/(\+page\.|help\/|embed\/)/;
+
+/** The help guides, which the server imports too (for the titles of the pages). */
+const guide = /\/src\/lib\/docs\/.*\.mdx$/;
+
+/**
+ * For the desktop app, empties the pages of the website, the help guides and the WebAssembly engine
+ * (the app has its own), so that their code, images and the module are not in the build.
+ */
+function desktopBuild(): Plugin {
+    return {
+        name: 'desktop-build',
+        enforce: 'pre',
+        load(id) {
+            const path = id.split('?')[0];
+            if (websitePage.test(path)) {
+                // no entries: the page is not prerendered
+                return path.endsWith('.server.ts') ? 'export const entries = () => [];' : '';
+            }
+            if (guide.test(path)) {
+                return "---\ntitle: ''\n---\n";
+            }
+            if (path.endsWith('/src/lib/engine/backend/wasm.ts')) {
+                return `export async function createWasmBackend() {
+                    throw new Error('The desktop app has no WebAssembly engine');
+                }`;
+            }
+        },
+    };
+}
+
 export default defineConfig({
-    plugins: [enhancedImages(), tailwindcss(), wasm(), sveltekit()],
+    plugins: [
+        ...(desktop ? [desktopBuild()] : []),
+        enhancedImages(),
+        tailwindcss(),
+        wasm(),
+        sveltekit(),
+    ],
 });