q12xo172i: Render post cards in the signed-in home feed

src/lib/feed-client.ts

@@ -0,0 +1,37 @@
+// Browser-side reader for the same-origin GET /api/feed route.
+
+export interface FeedPage {
+  items: unknown[];
+  nextCursor: string | null;
+}
+
+export class FeedLoadError extends Error {
+  constructor(public readonly signedOut: boolean) {
+    super(signedOut ? "sign_in" : "feed_unavailable");
+  }
+}
+
+export async function fetchFeedPage(
+  cursor: string | null,
+  fetchImpl: typeof fetch = fetch,
+): Promise<FeedPage> {
+  const qs = new URLSearchParams({ limit: "20" });
+  if (cursor) qs.set("cursor", cursor);
+  let res: Response;
+  try {
+    res = await fetchImpl(`/api/feed?${qs.toString()}`, { credentials: "same-origin" });
+  } catch {
+    throw new FeedLoadError(false);
+  }
+  if (res.status === 401) throw new FeedLoadError(true);
+  if (!res.ok) throw new FeedLoadError(false);
+  try {
+    const body = (await res.json()) as { items?: unknown; nextCursor?: unknown };
+    return {
+      items: Array.isArray(body.items) ? body.items : [],
+      nextCursor: typeof body.nextCursor === "string" && body.nextCursor ? body.nextCursor : null,
+    };
+  } catch {
+    throw new FeedLoadError(false);
+  }
+}