Initial QuestionGraph library and documentation

src/demo/docs-examples/SaveDraft.ts

@@ -0,0 +1,18 @@
+import type { QuestionnaireSaveHandler } from "../../lib";
+
+export const saveDraft: QuestionnaireSaveHandler = async request => {
+  const response = await fetch("/api/claims/current/draft", {
+    method: "PATCH",
+    headers: {
+      "Content-Type": "application/json",
+      "If-Match": JSON.stringify(request.revision),
+    },
+    body: JSON.stringify(request),
+  });
+
+  // Reject failures so the renderer stays on the page and allows a retry.
+  if (!response.ok) throw new Error("Could not save your answers.");
+
+  // The server returns { revision: number }.
+  return response.json();
+};