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

src/lib/feed-model.ts

@@ -0,0 +1,134 @@
+// Pure feed model: pick renderable posts out of raw feed items, normalise the
+// card fields, and keep one list sorted strictly by publishedAt, newest first.
+
+export interface CardMedia {
+  kind: "image" | "video";
+  /** Image source (images) or poster (videos). May be null for a bare video. */
+  src: string | null;
+}
+
+export interface CardPost {
+  key: string;
+  id: string | null;
+  authorName: string;
+  authorPictureUrl: string | null;
+  publishedAt: string | null;
+  time: number;
+  text: string;
+  likesCount: number;
+  commentsCount: number;
+  media: CardMedia[];
+}
+
+type Obj = Record<string, unknown>;
+
+function isObj(v: unknown): v is Obj {
+  return typeof v === "object" && v !== null && !Array.isArray(v);
+}
+function str(v: unknown): string | null {
+  return typeof v === "string" && v.trim() ? v : null;
+}
+function num(v: unknown): number {
+  return typeof v === "number" && Number.isFinite(v) ? v : 0;
+}
+
+export function initials(name: string): string {
+  const parts = name.trim().split(/\s+/).filter(Boolean);
+  if (parts.length === 0) return "?";
+  const first = parts[0][0] ?? "";
+  const last = parts.length > 1 ? (parts[parts.length - 1][0] ?? "") : "";
+  return (first + last).toUpperCase();
+}
+
+function authorName(author: Obj): string {
+  const display = str(author.displayName);
+  if (display) return display.trim();
+  const full = [str(author.firstName), str(author.lastName)].filter(Boolean).join(" ").trim();
+  return full || "Unknown";
+}
+
+function toMedia(raw: unknown): CardMedia[] {
+  if (!Array.isArray(raw)) return [];
+  const items = raw
+    .filter(isObj)
+    .map((m, i) => ({ m, i, order: typeof m.order === "number" ? m.order : i }))
+    .sort((a, b) => a.order - b.order || a.i - b.i);
+  const out: CardMedia[] = [];
+  for (const { m } of items) {
+    if (m.mediaType === "video") {
+      out.push({ kind: "video", src: str(m.thumbnailUrl) });
+      continue;
+    }
+    const src = str(m.imageMediumWebpUrl) ?? str(m.imageMediumUrl) ?? str(m.imageUrl);
+    if (src) out.push({ kind: "image", src });
+  }
+  return out;
+}
+
+/** The card for one raw feed item, or null when it is not a post. */
+export function toCardPost(item: unknown, index = 0): CardPost | null {
+  if (!isObj(item) || item.type !== "post" || !isObj(item.post)) return null;
+  const post = item.post;
+  const author = isObj(post.author) ? post.author : {};
+  const publishedAt = str(item.publishedAt);
+  const t = publishedAt ? Date.parse(publishedAt) : NaN;
+  const id =
+    typeof post.id === "string" || typeof post.id === "number" ? String(post.id) : null;
+  return {
+    key: id ?? `${publishedAt ?? "unknown"}#${index}`,
+    id,
+    authorName: authorName(author),
+    authorPictureUrl: str(author.profilePictureUrl),
+    publishedAt,
+    time: Number.isFinite(t) ? t : Number.NEGATIVE_INFINITY,
+    text: typeof post.content === "string" ? post.content : "",
+    likesCount: num(item.likesCount ?? post.likesCount),
+    commentsCount: num(item.commentsCount ?? post.commentsCount),
+    media: toMedia(post.mediaItems),
+  };
+}
+
+export function toCardPosts(items: unknown[]): CardPost[] {
+  const out: CardPost[] = [];
+  items.forEach((item, i) => {
+    const p = toCardPost(item, i);
+    if (p) out.push(p);
+  });
+  return out;
+}
+
+/** Newest first by publishedAt. Ties keep their given order. */
+export function sortByPublishedDesc(posts: CardPost[]): CardPost[] {
+  return posts
+    .map((p, i) => ({ p, i }))
+    .sort((a, b) => (a.p.time === b.p.time ? a.i - b.i : b.p.time > a.p.time ? 1 : -1))
+    .map((x) => x.p);
+}
+
+/** Merge lists, drop duplicates (first wins), and sort newest first. */
+export function mergePosts(...lists: CardPost[][]): CardPost[] {
+  const seen = new Set<string>();
+  const all: CardPost[] = [];
+  for (const list of lists) {
+    for (const p of list) {
+      if (seen.has(p.key)) continue;
+      seen.add(p.key);
+      all.push(p);
+    }
+  }
+  return sortByPublishedDesc(all);
+}
+
+export function relativeTime(publishedAt: string | null, now: number = Date.now()): string {
+  const t = publishedAt ? Date.parse(publishedAt) : NaN;
+  if (!Number.isFinite(t)) return "";
+  const s = Math.max(0, Math.floor((now - t) / 1000));
+  if (s < 60) return "just now";
+  const m = Math.floor(s / 60);
+  if (m < 60) return `${m}m ago`;
+  const h = Math.floor(m / 60);
+  if (h < 24) return `${h}h ago`;
+  const d = Math.floor(h / 24);
+  if (d < 7) return `${d}d ago`;
+  return new Date(t).toLocaleDateString("en-US", { month: "short", day: "numeric", year: "numeric" });
+}