feat: express responses

src/core/express/normalizeResponderReturnable.ts

@@ -0,0 +1,11 @@
+import { ResponderReturnable } from '../../server.js';
+import jsxToSvg from '../ui/jsxToSvg.js';
+
+export default async function normalizeResponderReturnable(
+  returnable: ResponderReturnable,
+) {
+  const awaitedReturnable = await returnable;
+  const svg = await jsxToSvg(awaitedReturnable);
+
+  return svg;
+}