Checkout: forward only the checkout fields, show clear errors, fix the contact form (#16)

Co-authored-by: Michael Czechowski <mail@librete.ch>

server/utils/cmsApi.ts

@@ -1,3 +1,5 @@
+import { cmsErrorLogLine, shopErrorFromCms } from "./cmsError";
+
 /**
  * Server-side CMS API utility.
  * Use this for direct CMS access during SSR.
@@ -15,3 +17,18 @@ export async function fetchCms<T>(endpoint: string, options: Parameters<typeof $
 		}
 	});
 }
+
+/**
+ * fetchCms for a route that forwards the browser's request to the CMS: a CMS error answers the browser with the CMS's status
+ * and the safe fields of its error (cmsError.ts), instead of an unhandled error, whose message and data Nitro hides.
+ */
+export async function forwardToCms<T>(endpoint: string, options: Parameters<typeof $fetch>[1] = {}): Promise<T> {
+	try {
+		return await fetchCms<T>(endpoint, options);
+	} catch (error) {
+		const shopError = shopErrorFromCms(error);
+		if (!shopError) throw error;
+		if (shopError.statusCode >= 500) console.error(cmsErrorLogLine(String(options.method ?? "GET"), endpoint, shopError));
+		throw createError(shopError);
+	}
+}