feat: Initial prototype

serve.mjs

@@ -0,0 +1,36 @@
+// Development server only. Deploy the frontend files to any HTTPS static host.
+import http from 'node:http';
+import {readFile} from 'node:fs/promises';
+import path from 'node:path';
+import {fileURLToPath} from 'node:url';
+
+const root = path.dirname(fileURLToPath(import.meta.url));
+const types = {
+    '.html': 'text/html; charset=utf-8', '.js': 'application/javascript',
+    '.css': 'text/css', '.svg': 'image/svg+xml', '.png': 'image/png',
+    '.webmanifest': 'application/manifest+json', '.woff2': 'font/woff2',
+};
+const port = Number(process.env.PORT || 8080);
+http.createServer(async (request, response) => {
+    try {
+        const url = new URL(request.url, 'http://localhost');
+        const filename = decodeURIComponent(url.pathname);
+        const target = path.resolve(root, `.${filename === '/' ? '/index.html' : filename}`);
+        if (!target.startsWith(root + path.sep)) {
+            response.writeHead(403).end();
+            return;
+        }
+        if (!['GET', 'HEAD'].includes(request.method)) {
+            response.writeHead(405, {Allow: 'GET, HEAD'}).end();
+            return;
+        }
+        const content = await readFile(target);
+        response.writeHead(200, {
+            'Content-Type': types[path.extname(target)] || 'application/octet-stream',
+            'Cache-Control': 'no-cache',
+        });
+        response.end(request.method === 'HEAD' ? undefined : content);
+    } catch {
+        response.writeHead(404).end('Not found');
+    }
+}).listen(port, '127.0.0.1', () => console.log(`ascii: http://localhost:${port}`));